Merge pull request 'update package' (#14) from va108xx-update-package into main

Reviewed-on: #14
2024-09-20 11:29:58 +02:00 · 2024-09-20 11:29:58 +02:00 · 501d1c973e
commit 501d1c973e
parent 405cc089c3 acb8b67ae7
40 changed files with 2197 additions and 673 deletions
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@ -39,7 +39,9 @@ jobs:
    steps:
      - uses: actions/checkout@v4
      - uses: dtolnay/rust-toolchain@nightly
-      - run: RUSTDOCFLAGS="--cfg docsrs --generate-link-to-definition -Z unstable-options" cargo +nightly doc --all-features
+      - run: RUSTDOCFLAGS="--cfg docsrs --generate-link-to-definition -Z unstable-options" cargo +nightly doc -p va108xx
+      - run: RUSTDOCFLAGS="--cfg docsrs --generate-link-to-definition -Z unstable-options" cargo +nightly doc -p va108xx-hal
+      - run: RUSTDOCFLAGS="--cfg docsrs --generate-link-to-definition -Z unstable-options" cargo +nightly doc -p vorago-reb1

  clippy:
    name: Clippy
--- a/Cargo.toml
+++ b/Cargo.toml
@ -5,7 +5,10 @@ members = [
 	"va108xx",
 	"va108xx-hal",
  "examples/simple",
+  "examples/rtic",
+  "examples/embassy",
  "board-tests",
+  "bootloader",
 ]

 exclude = [
@ -17,7 +20,8 @@ codegen-units = 1
 debug = 2
 debug-assertions = true # <-
 incremental = false
-opt-level = 'z'         # <-
+# This is problematic for stepping..
+# opt-level = 'z'         # <-
 overflow-checks = true  # <-

 # cargo build/run --release
@ -29,3 +33,12 @@ incremental = false
 lto = 'fat'
 opt-level = 3            # <-
 overflow-checks = false  # <-
+
+[profile.small]
+inherits = "release"
+codegen-units = 1
+debug-assertions = false # <-
+lto = true
+opt-level = 'z'            # <-
+overflow-checks = false  # <-
+strip = true  # Automatically strip symbols from the binary.
--- a/README.md
+++ b/README.md
@ -19,9 +19,13 @@ This workspace contains the following released crates:

 It also contains the following helper crates:

- The `board-tests` contains an application which can be used to test the libraries on the
-  board.
- The `examples` crates contains various example applications for the HAL and the PAC.
+- The [`board-tests`](https://egit.irs.uni-stuttgart.de/rust/va108xx-rs/src/branch/main/board-tests)
+  contains an application which can be used to test the libraries on the board.
+- The [`examples`](https://egit.irs.uni-stuttgart.de/rust/va108xx-rs/src/branch/main/examples)
+  folder contains various example applications crates using the HAL and the PAC.
+  This folder also contains dedicated example applications using the
+  [`RTIC`](https://rtic.rs/2/book/en/) and [`embassy`](https://github.com/embassy-rs/embassy)
+  native Rust RTOSes.

 ## Using the `.cargo/config.toml` file

@ -94,6 +98,8 @@ example.

 Assuming a working debug connection to your VA108xx board, you can debug using VS Code with
 the [`Cortex-Debug` plugin](https://marketplace.visualstudio.com/items?itemName=marus25.cortex-debug).
+Please make sure that [`objdump-multiarch` and `nm-multiarch`](https://forums.raspberrypi.com/viewtopic.php?t=333146)
+are installed as well.

 Some sample configuration files for VS code were provided and can be used by running
 `cp -rT vscode .vscode` like specified above. After that, you can use `Run and Debug`
@ -108,4 +114,5 @@ configuration variables in your `settings.json`:
 - `"cortex-debug.gdbPath.osx"`

 The provided VS Code configurations also provide an integrated RTT logger, which you can access
-via the terminal at `RTT Ch:0 console`.
+via the terminal at `RTT Ch:0 console`. In order for the RTT block address detection to
+work properly, `objdump-multiarch` and `nm-multiarch` need to be installed.
--- a/automation/Jenkinsfile
+++ b/automation/Jenkinsfile
@ -25,7 +25,9 @@ pipeline {
        stage('Docs') {
          steps {
            sh """
-              RUSTDOCFLAGS="--cfg docsrs --generate-link-to-definition -Z unstable-options" cargo +nightly doc --all-features
+              RUSTDOCFLAGS="--cfg docsrs --generate-link-to-definition -Z unstable-options" cargo +nightly doc -p va108xx
+              RUSTDOCFLAGS="--cfg docsrs --generate-link-to-definition -Z unstable-options" cargo +nightly doc -p va108xx-hal
+              RUSTDOCFLAGS="--cfg docsrs --generate-link-to-definition -Z unstable-options" cargo +nightly doc -p vorago-reb1
            """
          }
        }
--- a/board-tests/Cargo.toml
+++ b/board-tests/Cargo.toml
@ -4,10 +4,9 @@ version = "0.1.0"
 edition = "2021"

 [dependencies]
-cortex-m-rtic = "1"
-panic-halt = "0.2"
 cortex-m = { version = "0.7.6", features = ["critical-section-single-core"] }
 cortex-m-rt = "0.7"
+panic-halt = "0.2"
 rtt-target = "0.5"
 panic-rtt-target = "0.1.3"
 embedded-hal = "1"
--- a/bootloader/Cargo.toml
+++ b/bootloader/Cargo.toml
@ -0,0 +1,25 @@
+[package]
+name = "bootloader"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+cortex-m = "0.7"
+cortex-m-rt = "0.7"
+embedded-hal = "1"
+embedded-hal-bus = "0.2"
+dummy-pin = "1"
+panic-rtt-target = { version = "0.1.3" }
+panic-halt = { version = "0.2" }
+rtt-target = { version = "0.5" }
+crc = "3"
+
+[dependencies.va108xx-hal]
+path = "../va108xx-hal"
+
+[dependencies.vorago-reb1]
+path = "../vorago-reb1"
+
+[features]
+default = []
+rtt-panic = []
--- a/bootloader/src/lib.rs
+++ b/bootloader/src/lib.rs
@ -0,0 +1,10 @@
+#![no_std]
+
+use core::convert::Infallible;
+
+/// Simple trait which makes swapping the NVM easier. NVMs only need to implement this interface.
+pub trait NvmInterface {
+    fn write(&mut self, address: u32, data: &[u8]) -> Result<(), Infallible>;
+    fn read(&mut self, address: u32, buf: &mut [u8]) -> Result<(), Infallible>;
+    fn verify(&mut self, address: u32, data: &[u8]) -> Result<bool, Infallible>;
+}
--- a/bootloader/src/main.rs
+++ b/bootloader/src/main.rs
@ -0,0 +1,296 @@
+//! Vorago bootloader which can boot from two images.
+#![no_main]
+#![no_std]
+use bootloader::NvmInterface;
+use cortex_m_rt::entry;
+use crc::{Crc, CRC_16_IBM_3740};
+#[cfg(not(feature = "rtt-panic"))]
+use panic_halt as _;
+#[cfg(feature = "rtt-panic")]
+use panic_rtt_target as _;
+use rtt_target::{rprintln, rtt_init_print};
+use va108xx_hal::{pac, time::Hertz};
+use vorago_reb1::m95m01::M95M01;
+
+// Useful for debugging and see what the bootloader is doing. Enabled currently, because
+// the binary stays small enough.
+const RTT_PRINTOUT: bool = true;
+const DEBUG_PRINTOUTS: bool = false;
+
+// Dangerous option! An image with this option set to true will flash itself from RAM directly
+// into the NVM. This can be used as a recovery option from a direct RAM flash to fix the NVM
+// boot process. Please note that this will flash an image which will also always perform the
+// self-flash itself. It is recommended that you use a tool like probe-rs, Keil IDE, or a flash
+// loader to boot a bootloader without this feature.
+const FLASH_SELF: bool = false;
+
+// Register definitions for Cortex-M0 SCB register.
+pub const SCB_AIRCR_VECTKEY_POS: u32 = 16;
+pub const SCB_AIRCR_VECTKEY_MSK: u32 = 0xFFFF << SCB_AIRCR_VECTKEY_POS;
+
+pub const SCB_AIRCR_SYSRESETREQ_POS: u32 = 2;
+pub const SCB_AIRCR_SYSRESETREQ_MSK: u32 = 1 << SCB_AIRCR_SYSRESETREQ_POS;
+
+const CLOCK_FREQ: Hertz = Hertz::from_raw(50_000_000);
+
+// Important bootloader addresses and offsets, vector table information.
+
+const BOOTLOADER_START_ADDR: u32 = 0x0;
+const BOOTLOADER_CRC_ADDR: u32 = BOOTLOADER_END_ADDR - 2;
+// This is also the maximum size of the bootloader.
+const BOOTLOADER_END_ADDR: u32 = 0x3000;
+const APP_A_START_ADDR: u32 = 0x3000;
+const APP_A_SIZE_ADDR: u32 = APP_A_END_ADDR - 8;
+// Four bytes reserved, even when only 2 byte CRC is used. Leaves flexibility to switch to CRC32.
+const APP_A_CRC_ADDR: u32 = APP_A_END_ADDR - 4;
+pub const APP_A_END_ADDR: u32 = 0x11000;
+// The actual size of the image which is relevant for CRC calculation.
+const APP_B_START_ADDR: u32 = 0x11000;
+// The actual size of the image which is relevant for CRC calculation.
+const APP_B_SIZE_ADDR: u32 = APP_B_END_ADDR - 8;
+// Four bytes reserved, even when only 2 byte CRC is used. Leaves flexibility to switch to CRC32.
+const APP_B_CRC_ADDR: u32 = APP_B_END_ADDR - 4;
+pub const APP_B_END_ADDR: u32 = 0x20000;
+pub const APP_IMG_SZ: u32 = 0xE800;
+
+pub const VECTOR_TABLE_OFFSET: u32 = 0x0;
+pub const VECTOR_TABLE_LEN: u32 = 0xC0;
+pub const RESET_VECTOR_OFFSET: u32 = 0x4;
+
+const CRC_ALGO: Crc<u16> = Crc::<u16>::new(&CRC_16_IBM_3740);
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+enum AppSel {
+    A,
+    B,
+}
+
+pub struct NvmWrapper(pub M95M01);
+
+// Newtype pattern. We could now more easily swap the used NVM type.
+impl NvmInterface for NvmWrapper {
+    fn write(&mut self, address: u32, data: &[u8]) -> Result<(), core::convert::Infallible> {
+        self.0.write(address, data)
+    }
+
+    fn read(&mut self, address: u32, buf: &mut [u8]) -> Result<(), core::convert::Infallible> {
+        self.0.read(address, buf)
+    }
+
+    fn verify(&mut self, address: u32, data: &[u8]) -> Result<bool, core::convert::Infallible> {
+        self.0.verify(address, data)
+    }
+}
+
+#[entry]
+fn main() -> ! {
+    if RTT_PRINTOUT {
+        rtt_init_print!();
+        rprintln!("-- VA108xx bootloader --");
+    }
+    let mut dp = pac::Peripherals::take().unwrap();
+    let cp = cortex_m::Peripherals::take().unwrap();
+
+    let mut nvm = M95M01::new(&mut dp.sysconfig, CLOCK_FREQ, dp.spic);
+
+    if FLASH_SELF {
+        let mut first_four_bytes: [u8; 4] = [0; 4];
+        read_four_bytes_at_addr_zero(&mut first_four_bytes);
+        let bootloader_data = {
+            unsafe {
+                &*core::ptr::slice_from_raw_parts(
+                    (BOOTLOADER_START_ADDR + 4) as *const u8,
+                    (BOOTLOADER_END_ADDR - BOOTLOADER_START_ADDR - 6) as usize,
+                )
+            }
+        };
+        let mut digest = CRC_ALGO.digest();
+        digest.update(&first_four_bytes);
+        digest.update(bootloader_data);
+        let bootloader_crc = digest.finalize();
+
+        nvm.write(0x0, &first_four_bytes)
+            .expect("writing to NVM failed");
+        nvm.write(0x4, bootloader_data)
+            .expect("writing to NVM failed");
+        if let Err(e) = nvm.verify(0x0, &first_four_bytes) {
+            if RTT_PRINTOUT {
+                rprintln!("verification of self-flash to NVM failed: {:?}", e);
+            }
+        }
+        if let Err(e) = nvm.verify(0x4, bootloader_data) {
+            if RTT_PRINTOUT {
+                rprintln!("verification of self-flash to NVM failed: {:?}", e);
+            }
+        }
+
+        nvm.write(BOOTLOADER_CRC_ADDR, &bootloader_crc.to_be_bytes())
+            .expect("writing CRC failed");
+        if let Err(e) = nvm.verify(BOOTLOADER_CRC_ADDR, &bootloader_crc.to_be_bytes()) {
+            if RTT_PRINTOUT {
+                rprintln!(
+                    "error: CRC verification for bootloader self-flash failed: {:?}",
+                    e
+                );
+            }
+        }
+    }
+
+    let mut nvm = NvmWrapper(nvm);
+
+    // Check bootloader's CRC (and write it if blank)
+    check_own_crc(&dp.sysconfig, &cp, &mut nvm);
+
+    if check_app_crc(AppSel::A) {
+        boot_app(&dp.sysconfig, &cp, AppSel::A)
+    } else if check_app_crc(AppSel::B) {
+        boot_app(&dp.sysconfig, &cp, AppSel::B)
+    } else {
+        if DEBUG_PRINTOUTS && RTT_PRINTOUT {
+            rprintln!("both images corrupt! booting image A");
+        }
+        // TODO: Shift a CCSDS packet out to inform host/OBC about image corruption.
+        // Both images seem to be corrupt. Boot default image A.
+        boot_app(&dp.sysconfig, &cp, AppSel::A)
+    }
+}
+
+fn check_own_crc(sysconfig: &pac::Sysconfig, cp: &cortex_m::Peripherals, nvm: &mut NvmWrapper) {
+    let crc_exp = unsafe { (BOOTLOADER_CRC_ADDR as *const u16).read_unaligned().to_be() };
+    // I'd prefer to use [core::slice::from_raw_parts], but that is problematic
+    // because the address of the bootloader is 0x0, so the NULL check fails and the functions
+    // panics.
+    let mut first_four_bytes: [u8; 4] = [0; 4];
+    read_four_bytes_at_addr_zero(&mut first_four_bytes);
+    let mut digest = CRC_ALGO.digest();
+    digest.update(&first_four_bytes);
+    digest.update(unsafe {
+        &*core::ptr::slice_from_raw_parts(
+            (BOOTLOADER_START_ADDR + 4) as *const u8,
+            (BOOTLOADER_END_ADDR - BOOTLOADER_START_ADDR - 6) as usize,
+        )
+    });
+    let crc_calc = digest.finalize();
+    if crc_exp == 0x0000 || crc_exp == 0xffff {
+        if DEBUG_PRINTOUTS && RTT_PRINTOUT {
+            rprintln!("BL CRC blank - prog new CRC");
+        }
+        // Blank CRC, write it to NVM.
+        nvm.write(BOOTLOADER_CRC_ADDR, &crc_calc.to_be_bytes())
+            .expect("writing CRC failed");
+        // The Vorago bootloader resets here. I am not sure why this is done but I think it is
+        // necessary because somehow the boot will not work if we just continue as usual.
+        // cortex_m::peripheral::SCB::sys_reset();
+    } else if crc_exp != crc_calc {
+        // Bootloader is corrupted. Try to run App A.
+        if DEBUG_PRINTOUTS && RTT_PRINTOUT {
+            rprintln!(
+                "bootloader CRC corrupt, read {} and expected {}. booting image A immediately",
+                crc_calc,
+                crc_exp
+            );
+        }
+        // TODO: Shift out minimal CCSDS frame to notify about bootloader corruption.
+        boot_app(sysconfig, cp, AppSel::A);
+    }
+}
+
+// Reading from address 0x0 is problematic in Rust.
+// See https://users.rust-lang.org/t/reading-from-physical-address-0x0/117408/5.
+// This solution falls back to assembler to deal with this.
+fn read_four_bytes_at_addr_zero(buf: &mut [u8; 4]) {
+    unsafe {
+        core::arch::asm!(
+            "ldr r0, [{0}]",    // Load 4 bytes from src into r0 register
+            "str r0, [{1}]",    // Store r0 register into first_four_bytes
+            in(reg) BOOTLOADER_START_ADDR as *const u8,         // Input: src pointer (0x0)
+            in(reg) buf as *mut [u8; 4],  // Input: destination pointer
+        );
+    }
+}
+fn check_app_crc(app_sel: AppSel) -> bool {
+    if DEBUG_PRINTOUTS && RTT_PRINTOUT {
+        rprintln!("Checking image {:?}", app_sel);
+    }
+    if app_sel == AppSel::A {
+        check_app_given_addr(APP_A_CRC_ADDR, APP_A_START_ADDR, APP_A_SIZE_ADDR)
+    } else {
+        check_app_given_addr(APP_B_CRC_ADDR, APP_B_START_ADDR, APP_B_SIZE_ADDR)
+    }
+}
+
+fn check_app_given_addr(crc_addr: u32, start_addr: u32, image_size_addr: u32) -> bool {
+    let crc_exp = unsafe { (crc_addr as *const u16).read_unaligned().to_be() };
+    let image_size = unsafe { (image_size_addr as *const u32).read_unaligned().to_be() };
+    // Sanity check.
+    if image_size > APP_A_END_ADDR - APP_A_START_ADDR - 8 {
+        if RTT_PRINTOUT {
+            rprintln!("detected invalid app size {}", image_size);
+        }
+        return false;
+    }
+    let crc_calc = CRC_ALGO.checksum(unsafe {
+        core::slice::from_raw_parts(start_addr as *const u8, image_size as usize)
+    });
+    if crc_calc == crc_exp {
+        return true;
+    }
+    false
+}
+
+// The boot works by copying the interrupt vector table (IVT) of the respective app to the
+// base address in code RAM (0x0) and then performing a soft reset.
+fn boot_app(syscfg: &pac::Sysconfig, cp: &cortex_m::Peripherals, app_sel: AppSel) -> ! {
+    if DEBUG_PRINTOUTS && RTT_PRINTOUT {
+        rprintln!("booting app {:?}", app_sel);
+    }
+    // Disable ROM protection.
+    syscfg.rom_prot().write(|w| unsafe { w.bits(1) });
+    let base_addr = if app_sel == AppSel::A {
+        APP_A_START_ADDR
+    } else {
+        APP_B_START_ADDR
+    };
+    // Clear all interrupts set.
+    unsafe {
+        cp.NVIC.icer[0].write(0xFFFFFFFF);
+        cp.NVIC.icpr[0].write(0xFFFFFFFF);
+
+        // First 4 bytes done with inline assembly, writing to the physical address 0x0 can not
+        // be done without it. See https://users.rust-lang.org/t/reading-from-physical-address-0x0/117408/2.
+        core::ptr::read(base_addr as *const u32);
+        core::arch::asm!(
+            "str {0}, [{1}]",    // Load 4 bytes from src into r0 register
+            in(reg)  base_addr,  // Input: App vector table.
+            in(reg) BOOTLOADER_START_ADDR as *mut u32,  // Input: destination pointer
+        );
+        core::slice::from_raw_parts_mut(
+            (BOOTLOADER_START_ADDR + 4) as *mut u32,
+            (VECTOR_TABLE_LEN - 4) as usize,
+        )
+        .copy_from_slice(core::slice::from_raw_parts(
+            (base_addr + 4) as *const u32,
+            (VECTOR_TABLE_LEN - 4) as usize,
+        ));
+    }
+    /* Disable re-loading from FRAM/code ROM on soft reset */
+    syscfg
+        .rst_cntl_rom()
+        .modify(|_, w| w.sysrstreq().clear_bit());
+    soft_reset(cp);
+}
+
+// Soft reset based on https://github.com/ARM-software/CMSIS_6/blob/5782d6f8057906d360f4b95ec08a2354afe5c9b9/CMSIS/Core/Include/core_cm0.h#L874.
+fn soft_reset(cp: &cortex_m::Peripherals) -> ! {
+    // Ensure all outstanding memory accesses included buffered write are completed before reset.
+    cortex_m::asm::dsb();
+    unsafe {
+        cp.SCB
+            .aircr
+            .write((0x5FA << SCB_AIRCR_VECTKEY_POS) | SCB_AIRCR_SYSRESETREQ_MSK);
+    }
+    // Ensure completion of memory access.
+    cortex_m::asm::dsb();
+
+    unreachable!();
+}
--- a/examples/README.md
+++ b/examples/README.md
@ -0,0 +1,25 @@
+VA108xx Example Applications
+========
+
+This folder contains various examples
+Consult the main README first for setup of the repository.
+
+## Simple examples
+
+```rs
+cargo run --example blinky
+```
+
+You can have a look at the `simple/examples` folder to see all available simple examples
+
+## RTIC example
+
+```rs
+cargo run --bin rtic-example
+```
+
+## Embassy example
+
+```rs
+cargo run --bin embassy-example
+```
--- a/examples/embassy/Cargo.toml
+++ b/examples/embassy/Cargo.toml
@ -0,0 +1,40 @@
+[package]
+name = "embassy-example"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+cortex-m = { version = "0.7", features = ["critical-section-single-core"] }
+cortex-m-rt = "0.7"
+embedded-hal = "1"
+
+rtt-target = { version = "0.5" }
+panic-rtt-target = { version = "0.1" }
+critical-section = "1"
+portable-atomic = { version = "1", features = ["unsafe-assume-single-core"]}
+
+embassy-sync = { version = "0.6.0" }
+embassy-time = { version = "0.3.2" }
+embassy-time-driver = { version = "0.1" }
+
+[dependencies.once_cell]
+version = "1"
+default-features = false
+features = ["critical-section"]
+
+[dependencies.embassy-executor]
+version = "0.6.0"
+features = [
+    "arch-cortex-m",
+    "executor-thread",
+    "executor-interrupt",
+    "integrated-timers",
+]
+
+[dependencies.va108xx-hal]
+path = "../../va108xx-hal"
+
+[features]
+default = ["ticks-hz-1_000"]
+ticks-hz-1_000 = ["embassy-time/tick-hz-1_000"]
+ticks-hz-32_768 = ["embassy-time/tick-hz-32_768"]
--- a/examples/embassy/src/lib.rs
+++ b/examples/embassy/src/lib.rs
@ -0,0 +1,4 @@
+#![no_std]
+pub mod time_driver;
+
+pub use time_driver::init;
--- a/examples/embassy/src/main.rs
+++ b/examples/embassy/src/main.rs
@ -0,0 +1,43 @@
+#![no_std]
+#![no_main]
+use embassy_executor::Spawner;
+use embassy_time::{Duration, Instant, Ticker};
+use embedded_hal::digital::StatefulOutputPin;
+use panic_rtt_target as _;
+use rtt_target::{rprintln, rtt_init_print};
+use va108xx_hal::{gpio::PinsA, pac, prelude::*};
+
+const SYSCLK_FREQ: Hertz = Hertz::from_raw(50_000_000);
+
+// main is itself an async function.
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    rtt_init_print!();
+    rprintln!("-- VA108xx Embassy Demo --");
+
+    let mut dp = pac::Peripherals::take().unwrap();
+
+    // Safety: Only called once here.
+    unsafe {
+        embassy_example::init(
+            &mut dp.sysconfig,
+            &dp.irqsel,
+            SYSCLK_FREQ,
+            dp.tim23,
+            dp.tim22,
+        )
+    };
+
+    let porta = PinsA::new(&mut dp.sysconfig, Some(dp.ioconfig), dp.porta);
+    let mut led0 = porta.pa10.into_readable_push_pull_output();
+    let mut led1 = porta.pa7.into_readable_push_pull_output();
+    let mut led2 = porta.pa6.into_readable_push_pull_output();
+    let mut ticker = Ticker::every(Duration::from_secs(1));
+    loop {
+        ticker.next().await;
+        rprintln!("Current time: {}", Instant::now().as_secs());
+        led0.toggle().ok();
+        led1.toggle().ok();
+        led2.toggle().ok();
+    }
+}
--- a/examples/embassy/src/time_driver.rs
+++ b/examples/embassy/src/time_driver.rs
@ -0,0 +1,333 @@
+//! This is a sample time driver implementation for the VA108xx family of devices, supporting
+//! one alarm and requiring/reserving 2 TIM peripherals. You could adapt this implementation to
+//! support more alarms.
+//!
+//! This driver implementation reserves interrupts OC31 and OC30 for the timekeeping.
+use core::{cell::Cell, mem, ptr};
+use critical_section::CriticalSection;
+use embassy_sync::blocking_mutex::raw::CriticalSectionRawMutex;
+use embassy_sync::blocking_mutex::Mutex;
+use portable_atomic::{AtomicU32, AtomicU8, Ordering};
+
+use embassy_time_driver::{time_driver_impl, AlarmHandle, Driver, TICK_HZ};
+use once_cell::sync::OnceCell;
+use va108xx_hal::{
+    clock::enable_peripheral_clock,
+    enable_interrupt,
+    pac::{self, interrupt},
+    prelude::*,
+    timer::{enable_tim_clk, ValidTim},
+    PeripheralSelect,
+};
+
+pub type TimekeeperClk = pac::Tim23;
+pub type AlarmClk0 = pac::Tim22;
+pub type AlarmClk1 = pac::Tim21;
+pub type AlarmClk2 = pac::Tim20;
+
+const TIMEKEEPER_IRQ: pac::Interrupt = pac::Interrupt::OC31;
+const ALARM_IRQ: pac::Interrupt = pac::Interrupt::OC30;
+
+/// Initialization method for embassy
+///
+/// # Safety
+/// This has to be called once at initialization time to initiate the time driver for
+/// embassy.
+pub unsafe fn init(
+    syscfg: &mut pac::Sysconfig,
+    irqsel: &pac::Irqsel,
+    sysclk: impl Into<Hertz>,
+    timekeeper: TimekeeperClk,
+    alarm_tim: AlarmClk0,
+) {
+    DRIVER.init(syscfg, irqsel, sysclk, timekeeper, alarm_tim)
+}
+
+time_driver_impl!(
+    static DRIVER: TimerDriverEmbassy = TimerDriverEmbassy {
+        periods: AtomicU32::new(0),
+        alarm_count: AtomicU8::new(0),
+        alarms: Mutex::const_new(CriticalSectionRawMutex::new(), [AlarmState::new(); ALARM_COUNT])
+});
+
+/// Timekeeper interrupt.
+#[interrupt]
+#[allow(non_snake_case)]
+fn OC31() {
+    DRIVER.on_interrupt_timekeeping()
+}
+
+/// Alarm timer interrupt.
+#[interrupt]
+#[allow(non_snake_case)]
+fn OC30() {
+    DRIVER.on_interrupt_alarm(0)
+}
+
+#[inline(always)]
+const fn alarm_tim(idx: usize) -> &'static pac::tim0::RegisterBlock {
+    // Safety: This is a static memory-mapped peripheral.
+    match idx {
+        0 => unsafe { &*AlarmClk0::ptr() },
+        1 => unsafe { &*AlarmClk1::ptr() },
+        2 => unsafe { &*AlarmClk2::ptr() },
+        _ => {
+            panic!("invalid alarm timer index")
+        }
+    }
+}
+
+#[inline(always)]
+const fn timekeeping_tim() -> &'static pac::tim0::RegisterBlock {
+    // Safety: This is a memory-mapped peripheral.
+    unsafe { &*TimekeeperClk::ptr() }
+}
+
+struct AlarmState {
+    timestamp: Cell<u64>,
+
+    // This is really a Option<(fn(*mut ()), *mut ())>
+    // but fn pointers aren't allowed in const yet
+    callback: Cell<*const ()>,
+    ctx: Cell<*mut ()>,
+}
+
+impl AlarmState {
+    const fn new() -> Self {
+        Self {
+            timestamp: Cell::new(u64::MAX),
+            callback: Cell::new(ptr::null()),
+            ctx: Cell::new(ptr::null_mut()),
+        }
+    }
+}
+
+unsafe impl Send for AlarmState {}
+
+const ALARM_COUNT: usize = 1;
+
+static SCALE: OnceCell<u64> = OnceCell::new();
+
+pub struct TimerDriverEmbassy {
+    periods: AtomicU32,
+    alarm_count: AtomicU8,
+    /// Timestamp at which to fire alarm. u64::MAX if no alarm is scheduled.
+    alarms: Mutex<CriticalSectionRawMutex, [AlarmState; ALARM_COUNT]>,
+}
+
+impl TimerDriverEmbassy {
+    fn init(
+        &self,
+        syscfg: &mut pac::Sysconfig,
+        irqsel: &pac::Irqsel,
+        sysclk: impl Into<Hertz>,
+        timekeeper: TimekeeperClk,
+        alarm_tim: AlarmClk0,
+    ) {
+        enable_peripheral_clock(syscfg, PeripheralSelect::Irqsel);
+        enable_tim_clk(syscfg, TimekeeperClk::TIM_ID);
+        let sysclk = sysclk.into();
+        // Initiate scale value here. This is required to convert timer ticks back to a timestamp.
+        SCALE.set((sysclk.raw() / TICK_HZ as u32) as u64).unwrap();
+        timekeeper
+            .rst_value()
+            .write(|w| unsafe { w.bits(u32::MAX) });
+        // Decrementing counter.
+        timekeeper
+            .cnt_value()
+            .write(|w| unsafe { w.bits(u32::MAX) });
+        // Switch on. Timekeeping should always be done.
+        irqsel
+            .tim0(TimekeeperClk::TIM_ID as usize)
+            .write(|w| unsafe { w.bits(TIMEKEEPER_IRQ as u32) });
+        unsafe {
+            enable_interrupt(TIMEKEEPER_IRQ);
+        }
+        timekeeper.ctrl().modify(|_, w| w.irq_enb().set_bit());
+        timekeeper.enable().write(|w| unsafe { w.bits(1) });
+
+        enable_tim_clk(syscfg, AlarmClk0::TIM_ID);
+
+        // Explicitely disable alarm timer until needed.
+        alarm_tim.ctrl().modify(|_, w| {
+            w.irq_enb().clear_bit();
+            w.enable().clear_bit()
+        });
+        // Enable general interrupts. The IRQ enable of the peripheral remains cleared.
+        unsafe {
+            enable_interrupt(ALARM_IRQ);
+        }
+        irqsel
+            .tim0(AlarmClk0::TIM_ID as usize)
+            .write(|w| unsafe { w.bits(ALARM_IRQ as u32) });
+    }
+
+    // Should be called inside the IRQ of the timekeeper timer.
+    fn on_interrupt_timekeeping(&self) {
+        self.next_period();
+    }
+
+    // Should be called inside the IRQ of the alarm timer.
+    fn on_interrupt_alarm(&self, idx: usize) {
+        critical_section::with(|cs| {
+            if self.alarms.borrow(cs)[idx].timestamp.get() <= self.now() {
+                self.trigger_alarm(idx, cs)
+            }
+        })
+    }
+
+    fn next_period(&self) {
+        let period = self.periods.fetch_add(1, Ordering::AcqRel) + 1;
+        let t = (period as u64) << 32;
+        critical_section::with(|cs| {
+            for i in 0..ALARM_COUNT {
+                let alarm = &self.alarms.borrow(cs)[i];
+                let at = alarm.timestamp.get();
+                let alarm_tim = alarm_tim(0);
+                if at < t {
+                    self.trigger_alarm(i, cs);
+                } else {
+                    let remaining_ticks = (at - t) * *SCALE.get().unwrap();
+                    if remaining_ticks <= u32::MAX as u64 {
+                        alarm_tim.enable().write(|w| unsafe { w.bits(0) });
+                        alarm_tim
+                            .cnt_value()
+                            .write(|w| unsafe { w.bits(remaining_ticks as u32) });
+                        alarm_tim.ctrl().modify(|_, w| w.irq_enb().set_bit());
+                        alarm_tim.enable().write(|w| unsafe { w.bits(1) })
+                    }
+                }
+            }
+        })
+    }
+
+    fn get_alarm<'a>(&'a self, cs: CriticalSection<'a>, alarm: AlarmHandle) -> &'a AlarmState {
+        // safety: we're allowed to assume the AlarmState is created by us, and
+        // we never create one that's out of bounds.
+        unsafe { self.alarms.borrow(cs).get_unchecked(alarm.id() as usize) }
+    }
+
+    fn trigger_alarm(&self, n: usize, cs: CriticalSection) {
+        alarm_tim(n).ctrl().modify(|_, w| {
+            w.irq_enb().clear_bit();
+            w.enable().clear_bit()
+        });
+
+        let alarm = &self.alarms.borrow(cs)[n];
+        // Setting the maximum value disables the alarm.
+        alarm.timestamp.set(u64::MAX);
+
+        // Call after clearing alarm, so the callback can set another alarm.
+
+        // safety:
+        // - we can ignore the possiblity of `f` being unset (null) because of the safety contract of `allocate_alarm`.
+        // - other than that we only store valid function pointers into alarm.callback
+        let f: fn(*mut ()) = unsafe { mem::transmute(alarm.callback.get()) };
+        f(alarm.ctx.get());
+    }
+}
+
+impl Driver for TimerDriverEmbassy {
+    fn now(&self) -> u64 {
+        if SCALE.get().is_none() {
+            return 0;
+        }
+        let mut period1: u32;
+        let mut period2: u32;
+        let mut counter_val: u32;
+
+        loop {
+            // Acquire ensures that we get the latest value of `periods` and
+            // no instructions can be reordered before the load.
+            period1 = self.periods.load(Ordering::Acquire);
+
+            counter_val = u32::MAX - timekeeping_tim().cnt_value().read().bits();
+
+            // Double read to protect against race conditions when the counter is overflowing.
+            period2 = self.periods.load(Ordering::Relaxed);
+            if period1 == period2 {
+                let now = (((period1 as u64) << 32) | counter_val as u64) / *SCALE.get().unwrap();
+                return now;
+            }
+        }
+    }
+
+    unsafe fn allocate_alarm(&self) -> Option<AlarmHandle> {
+        let id = self
+            .alarm_count
+            .fetch_update(Ordering::AcqRel, Ordering::Acquire, |x| {
+                if x < ALARM_COUNT as u8 {
+                    Some(x + 1)
+                } else {
+                    None
+                }
+            });
+
+        match id {
+            Ok(id) => Some(AlarmHandle::new(id)),
+            Err(_) => None,
+        }
+    }
+
+    fn set_alarm_callback(
+        &self,
+        alarm: embassy_time_driver::AlarmHandle,
+        callback: fn(*mut ()),
+        ctx: *mut (),
+    ) {
+        critical_section::with(|cs| {
+            let alarm = self.get_alarm(cs, alarm);
+
+            alarm.callback.set(callback as *const ());
+            alarm.ctx.set(ctx);
+        })
+    }
+
+    fn set_alarm(&self, alarm: embassy_time_driver::AlarmHandle, timestamp: u64) -> bool {
+        if SCALE.get().is_none() {
+            return false;
+        }
+        critical_section::with(|cs| {
+            let n = alarm.id();
+            let alarm_tim = alarm_tim(n.into());
+            alarm_tim.ctrl().modify(|_, w| {
+                w.irq_enb().clear_bit();
+                w.enable().clear_bit()
+            });
+
+            let alarm = self.get_alarm(cs, alarm);
+            alarm.timestamp.set(timestamp);
+
+            let t = self.now();
+            if timestamp <= t {
+                alarm.timestamp.set(u64::MAX);
+                return false;
+            }
+
+            // If it hasn't triggered yet, setup the relevant reset value, regardless of whether
+            // the interrupts are enabled or not. When they are enabled at a later point, the
+            // right value is already set.
+
+            // If the timestamp is in the next few ticks, add a bit of buffer to be sure the alarm
+            // is not missed.
+            //
+            // This means that an alarm can be delayed for up to 2 ticks (from t+1 to t+3), but this is allowed
+            // by the Alarm trait contract. What's not allowed is triggering alarms *before* their scheduled time,
+            // and we don't do that here.
+            let safe_timestamp = timestamp.max(t + 3);
+            let timer_ticks = (safe_timestamp - t) * *SCALE.get().unwrap();
+            alarm_tim.rst_value().write(|w| unsafe { w.bits(u32::MAX) });
+            if timer_ticks <= u32::MAX as u64 {
+                alarm_tim
+                    .cnt_value()
+                    .write(|w| unsafe { w.bits(timer_ticks as u32) });
+                alarm_tim.ctrl().modify(|_, w| w.irq_enb().set_bit());
+                alarm_tim.enable().write(|w| unsafe { w.bits(1) });
+            }
+            // If it's too far in the future, don't enable timer yet.
+            // It will be enabled later by `next_period`.
+
+            true
+        })
+    }
+}
--- a/examples/rtic/Cargo.toml
+++ b/examples/rtic/Cargo.toml
@ -0,0 +1,33 @@
+[package]
+name = "rtic-example"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+cortex-m = { version = "0.7", features = ["critical-section-single-core"] }
+cortex-m-rt = "0.7"
+embedded-hal = "1"
+embedded-io = "0.6"
+rtt-target = { version = "0.5" }
+# Even though we do not use this directly, we need to activate this feature explicitely
+# so that RTIC compiles because thumv6 does not have CAS operations natively.
+portable-atomic = { version = "1", features = ["unsafe-assume-single-core"]}
+panic-rtt-target = { version = "0.1" }
+
+[dependencies.va108xx-hal]
+path = "../../va108xx-hal"
+
+[dependencies.vorago-reb1]
+path = "../../vorago-reb1"
+
+[dependencies.rtic]
+version = "2"
+features = ["thumbv6-backend"]
+
+[dependencies.rtic-monotonics]
+version = "2"
+features = ["cortex-m-systick"]
+
+[dependencies.rtic-sync]
+version = "1.3"
+features = ["defmt-03"]
--- a/examples/rtic/src/bin/blinky-button-rtic.rs
+++ b/examples/rtic/src/bin/blinky-button-rtic.rs
@ -5,7 +5,7 @@
 #[rtic::app(device = pac)]
 mod app {
    use panic_rtt_target as _;
-    use rtic_monotonics::systick::Systick;
+    use rtic_example::SYSCLK_FREQ;
    use rtt_target::{rprintln, rtt_init_default, set_print_channel};
    use va108xx_hal::{
        clock::{set_clk_div_register, FilterClkSel},
@ -17,6 +17,8 @@ mod app {
    use vorago_reb1::button::Button;
    use vorago_reb1::leds::Leds;

+    rtic_monotonics::systick_monotonic!(Mono, 1_000);
+
    #[derive(Debug, PartialEq)]
    pub enum PressMode {
        Toggle,
@ -44,17 +46,11 @@ mod app {
    struct Shared {}

    #[init]
-    fn init(ctx: init::Context) -> (Shared, Local) {
+    fn init(cx: init::Context) -> (Shared, Local) {
        let channels = rtt_init_default!();
        set_print_channel(channels.up.0);
        rprintln!("-- Vorago Button IRQ Example --");
-        // Initialize the systick interrupt & obtain the token to prove that we did
-        let systick_mono_token = rtic_monotonics::create_systick_token!();
-        Systick::start(
-            ctx.core.SYST,
-            Hertz::from(50.MHz()).raw(),
-            systick_mono_token,
-        );
+        Mono::start(cx.core.SYST, SYSCLK_FREQ.raw());

        let mode = match CFG_MODE {
            // Ask mode from user via RTT
@ -64,7 +60,7 @@ mod app {
        };
        rprintln!("Using {:?} mode", mode);

-        let mut dp = ctx.device;
+        let mut dp = cx.device;
        let pinsa = PinsA::new(&mut dp.sysconfig, Some(dp.ioconfig), dp.porta);
        let edge_irq = match mode {
            PressMode::Toggle => InterruptEdge::HighToLow,
@ -117,14 +113,12 @@ mod app {
        let mode = cx.local.mode;
        if *mode == PressMode::Toggle {
            leds[0].toggle();
-        } else {
-            if button.released() {
+        } else if button.released() {
            leds[0].off();
        } else {
            leds[0].on();
        }
    }
-    }

    #[task(binds = OC0)]
    fn ms_tick(_cx: ms_tick::Context) {
@ -138,14 +132,11 @@ mod app {
        let mut read;
        loop {
            read = down_channel.read(&mut read_buf);
-            for i in 0..read {
-                let val = read_buf[i] as char;
-                if val == '0' || val == '1' {
-                    return if val == '0' {
-                        PressMode::Toggle
-                    } else {
-                        PressMode::Keep
-                    };
+            for &byte in &read_buf[..read] {
+                match byte as char {
+                    '0' => return PressMode::Toggle,
+                    '1' => return PressMode::Keep,
+                    _ => continue, // Ignore other characters
                }
            }
        }
--- a/examples/simple/examples/rtic-empty.rs
+++ b/examples/simple/examples/rtic-empty.rs
--- a/examples/simple/examples/uart-irq-rtic.rs
+++ b/examples/simple/examples/uart-irq-rtic.rs
@ -14,14 +14,13 @@
 mod app {
    use embedded_io::Write;
    use panic_rtt_target as _;
-    use rtic_monotonics::systick::Systick;
+    use rtic_example::SYSCLK_FREQ;
    use rtic_sync::make_channel;
    use rtt_target::{rprintln, rtt_init_print};
    use va108xx_hal::{
        gpio::PinsB,
        pac,
        prelude::*,
-        time::Hertz,
        uart::{self, IrqCfg, IrqResult, UartWithIrqBase},
    };

@ -44,19 +43,14 @@ mod app {
        pub timeout: bool,
    }

+    rtic_monotonics::systick_monotonic!(Mono, 1_000);
+
    #[init]
    fn init(cx: init::Context) -> (Shared, Local) {
        rtt_init_print!();
-        //set_print_channel(channels.up.0);
        rprintln!("-- VA108xx UART IRQ example application--");

-        // Initialize the systick interrupt & obtain the token to prove that we did
-        let systick_mono_token = rtic_monotonics::create_systick_token!();
-        Systick::start(
-            cx.core.SYST,
-            Hertz::from(50.MHz()).raw(),
-            systick_mono_token,
-        );
+        Mono::start(cx.core.SYST, SYSCLK_FREQ.raw());

        let mut dp = cx.device;
        let gpiob = PinsB::new(&mut dp.sysconfig, Some(dp.ioconfig), dp.portb);
@ -74,7 +68,6 @@ mod app {

        let (rx_info_tx, rx_info_rx) = make_channel!(RxInfo, 3);
        let rx_buf: [u8; 64] = [0; 64];
-        //reply_handler::spawn().expect("spawning reply handler failed");
        (
            Shared { irq_uart, rx_buf },
            Local {
@ -112,8 +105,8 @@ mod app {
                            .expect("Read operation init failed");

                        let mut end_idx = 0;
-                        for idx in 0..rx_buf.len() {
-                            if (rx_buf[idx] as char) == '\n' {
+                        for (idx, val) in rx_buf.iter().enumerate() {
+                            if (*val as char) == '\n' {
                                end_idx = idx;
                                break;
                            }
--- a/examples/rtic/src/lib.rs
+++ b/examples/rtic/src/lib.rs
@ -0,0 +1,4 @@
+#![no_std]
+use va108xx_hal::time::Hertz;
+
+pub const SYSCLK_FREQ: Hertz = Hertz::from_raw(50_000_000);
--- a/examples/rtic/src/main.rs
+++ b/examples/rtic/src/main.rs
@ -0,0 +1,71 @@
+//! RTIC minimal blinky
+#![no_main]
+#![no_std]
+
+#[rtic::app(device = pac, dispatchers = [OC31, OC30, OC29])]
+mod app {
+    use cortex_m::asm;
+    use embedded_hal::digital::StatefulOutputPin;
+    use panic_rtt_target as _;
+    use rtic_example::SYSCLK_FREQ;
+    use rtic_monotonics::systick::prelude::*;
+    use rtic_monotonics::Monotonic;
+    use rtt_target::{rprintln, rtt_init_print};
+    use va108xx_hal::{
+        gpio::{OutputReadablePushPull, Pin, PinsA, PA10, PA6, PA7},
+        pac,
+    };
+
+    #[local]
+    struct Local {
+        led0: Pin<PA10, OutputReadablePushPull>,
+        led1: Pin<PA7, OutputReadablePushPull>,
+        led2: Pin<PA6, OutputReadablePushPull>,
+    }
+
+    #[shared]
+    struct Shared {}
+
+    rtic_monotonics::systick_monotonic!(Mono, 1_000);
+
+    #[init]
+    fn init(mut cx: init::Context) -> (Shared, Local) {
+        rtt_init_print!();
+        rprintln!("-- Vorago VA108xx RTIC template --");
+
+        Mono::start(cx.core.SYST, SYSCLK_FREQ.raw());
+
+        let porta = PinsA::new(
+            &mut cx.device.sysconfig,
+            Some(cx.device.ioconfig),
+            cx.device.porta,
+        );
+        let led0 = porta.pa10.into_readable_push_pull_output();
+        let led1 = porta.pa7.into_readable_push_pull_output();
+        let led2 = porta.pa6.into_readable_push_pull_output();
+        blinky::spawn().ok();
+        (Shared {}, Local { led0, led1, led2 })
+    }
+
+    // `shared` cannot be accessed from this context
+    #[idle]
+    fn idle(_cx: idle::Context) -> ! {
+        loop {
+            asm::nop();
+        }
+    }
+
+    #[task(
+        priority = 3,
+        local=[led0, led1, led2],
+    )]
+    async fn blinky(cx: blinky::Context) {
+        loop {
+            rprintln!("toggling LEDs");
+            cx.local.led0.toggle().ok();
+            cx.local.led1.toggle().ok();
+            cx.local.led2.toggle().ok();
+            Mono::delay(1000.millis()).await;
+        }
+    }
+}
--- a/examples/simple/Cargo.toml
+++ b/examples/simple/Cargo.toml
@ -4,30 +4,20 @@ version = "0.1.0"
 edition = "2021"

 [dependencies]
-panic-halt = "0.2"
 cortex-m = {version = "0.7", features = ["critical-section-single-core"]}
-panic-rtt-target = "0.1"
 cortex-m-rt = "0.7"
+panic-halt = "0.2"
+panic-rtt-target = "0.1"
+critical-section = "1"
 rtt-target = "0.5"
-rtic-sync = { version = "1.3", features = ["defmt-03"] }
 embedded-hal = "1"
 embedded-hal-nb = "1"
 embedded-io = "0.6"
 cortex-m-semihosting = "0.5.0"
-# I'd really like to use those, but it is tricky without probe-rs..
-# defmt = "0.3"
-# defmt-brtt = { version = "0.1", default-features = false, features = ["rtt"] }
-# panic-probe = { version = "0.3", features = ["print-defmt"] }
-
-[dependencies.rtic]
-version = "2"
-features = ["thumbv6-backend"]
-
-[dependencies.rtic-monotonics]
-version = "1"
-features = ["cortex-m-systick"]

 [dependencies.va108xx-hal]
-version = "0.7"
 path = "../../va108xx-hal"
 features = ["rt", "defmt"]
+
+[dependencies.vorago-reb1]
+path = "../../vorago-reb1"
--- a/examples/simple/examples/cascade.rs
+++ b/examples/simple/examples/cascade.rs
@ -48,7 +48,7 @@ fn main() -> ! {
    let mut cascade_target_1 =
        CountDownTimer::new(&mut dp.sysconfig, 50.MHz(), dp.tim4).auto_deactivate(true);
    cascade_target_1
-        .cascade_0_source(CascadeSource::TimBase, Some(3))
+        .cascade_0_source(CascadeSource::Tim(3))
        .expect("Configuring cascade source for TIM4 failed");
    let mut csd_cfg = CascadeCtrl {
        enb_start_src_csd0: true,
@ -75,7 +75,7 @@ fn main() -> ! {
        CountDownTimer::new(&mut dp.sysconfig, 50.MHz(), dp.tim5).auto_deactivate(true);
    // Set TIM4 as cascade source
    cascade_target_2
-        .cascade_1_source(CascadeSource::TimBase, Some(4))
+        .cascade_1_source(CascadeSource::Tim(4))
        .expect("Configuring cascade source for TIM5 failed");

    csd_cfg = CascadeCtrl::default();
--- a/examples/simple/examples/spi.rs
+++ b/examples/simple/examples/spi.rs
@ -16,7 +16,7 @@ use va108xx_hal::{
    pac::{self, interrupt},
    prelude::*,
    pwm::{default_ms_irq_handler, set_up_ms_tick},
-    spi::{self, Spi, SpiBase, TransferConfig},
+    spi::{self, Spi, SpiBase, SpiClkConfig, TransferConfigWithHwcs},
    IrqCfg,
 };

@ -24,8 +24,7 @@ use va108xx_hal::{
 pub enum ExampleSelect {
    // Enter loopback mode. It is not necessary to tie MOSI/MISO together for this
    Loopback,
-    // Send a test buffer and print everything received
-    TestBuffer,
+    MosiMisoTiedTogetherManually,
 }

 #[derive(PartialEq, Debug)]
@ -55,6 +54,8 @@ fn main() -> ! {
        dp.tim0,
    );

+    let spi_clk_cfg = SpiClkConfig::from_clk(50.MHz(), SPI_SPEED_KHZ.kHz())
+        .expect("creating SPI clock config failed");
    let spia_ref: RefCell<Option<SpiBase<pac::Spia, u8>>> = RefCell::new(None);
    let spib_ref: RefCell<Option<SpiBase<pac::Spib, u8>>> = RefCell::new(None);
    let pinsa = PinsA::new(&mut dp.sysconfig, None, dp.porta);
@ -79,7 +80,6 @@ fn main() -> ! {
                dp.spia,
                (sck, miso, mosi),
                spi_cfg,
-                None,
            );
            spia.set_fill_word(FILL_WORD);
            spia_ref.borrow_mut().replace(spia.downgrade());
@ -96,7 +96,6 @@ fn main() -> ! {
                dp.spia,
                (sck, miso, mosi),
                spi_cfg,
-                None,
            );
            spia.set_fill_word(FILL_WORD);
            spia_ref.borrow_mut().replace(spia.downgrade());
@ -113,7 +112,6 @@ fn main() -> ! {
                dp.spib,
                (sck, miso, mosi),
                spi_cfg,
-                None,
            );
            spib.set_fill_word(FILL_WORD);
            spib_ref.borrow_mut().replace(spib.downgrade());
@ -123,17 +121,21 @@ fn main() -> ! {
    match SPI_BUS_SEL {
        SpiBusSelect::SpiAPortA | SpiBusSelect::SpiAPortB => {
            if let Some(ref mut spi) = *spia_ref.borrow_mut() {
-                let transfer_cfg =
-                    TransferConfig::new_no_hw_cs(SPI_SPEED_KHZ.kHz(), SPI_MODE, BLOCKMODE, false);
+                let transfer_cfg = TransferConfigWithHwcs::new_no_hw_cs(
+                    Some(spi_clk_cfg),
+                    Some(SPI_MODE),
+                    BLOCKMODE,
+                    false,
+                );
                spi.cfg_transfer(&transfer_cfg);
            }
        }
        SpiBusSelect::SpiBPortB => {
            if let Some(ref mut spi) = *spib_ref.borrow_mut() {
                let hw_cs_pin = pinsb.pb2.into_funsel_1();
-                let transfer_cfg = TransferConfig::new(
-                    SPI_SPEED_KHZ.kHz(),
-                    SPI_MODE,
+                let transfer_cfg = TransferConfigWithHwcs::new(
+                    Some(spi_clk_cfg),
+                    Some(SPI_MODE),
                    Some(hw_cs_pin),
                    BLOCKMODE,
                    false,
@ -149,7 +151,6 @@ fn main() -> ! {
        match SPI_BUS_SEL {
            SpiBusSelect::SpiAPortA | SpiBusSelect::SpiAPortB => {
                if let Some(ref mut spi) = *spia_ref.borrow_mut() {
-                    if EXAMPLE_SEL == ExampleSelect::Loopback {
                    // Can't really verify correct reply here.
                    spi.write(&[0x42]).expect("write failed");
                    // Because of the loopback mode, we should get back the fill word here.
@ -177,28 +178,12 @@ fn main() -> ! {
                        tx_rx_buf[2]
                    );
                    assert_eq!(&tx_rx_buf[0..3], &[0x03, 0x02, 0x01]);
-                    } else {
-                        let send_buf: [u8; 3] = [0x01, 0x02, 0x03];
-                        spi.transfer(&mut reply_buf[0..3], &send_buf).unwrap();
-                        rprintln!(
-                            "Received reply: {}, {}, {}",
-                            reply_buf[0],
-                            reply_buf[1],
-                            reply_buf[2]
-                        );
-                        delay.delay_ms(1000_u32);
-                    }
                }
            }
            SpiBusSelect::SpiBPortB => {
                if let Some(ref mut spi) = *spib_ref.borrow_mut() {
-                    if EXAMPLE_SEL == ExampleSelect::Loopback {
                    // Can't really verify correct reply here.
                    spi.write(&[0x42]).expect("write failed");
-                        // Need small delay.. otherwise we will read back the sent byte (which we don't want here).
-                        // The write function will return as soon as all bytes were shifted out, ignoring the
-                        // reply bytes.
-                        delay.delay_us(50);
                    // Because of the loopback mode, we should get back the fill word here.
                    spi.read(&mut reply_buf[0..1]).unwrap();
                    assert_eq!(reply_buf[0], FILL_WORD);
@ -224,17 +209,6 @@ fn main() -> ! {
                        tx_rx_buf[2]
                    );
                    assert_eq!(&tx_rx_buf[0..3], &[0x03, 0x02, 0x01]);
-                    } else {
-                        let send_buf: [u8; 3] = [0x01, 0x02, 0x03];
-                        spi.transfer(&mut reply_buf[0..3], &send_buf).unwrap();
-                        rprintln!(
-                            "Received reply: {}, {}, {}",
-                            reply_buf[0],
-                            reply_buf[1],
-                            reply_buf[2]
-                        );
-                        delay.delay_ms(1000_u32);
-                    }
                }
            }
        }
--- a/examples/simple/examples/timer-ticks.rs
+++ b/examples/simple/examples/timer-ticks.rs
@ -3,8 +3,8 @@
 #![no_std]

 use core::cell::Cell;
-use cortex_m::interrupt::Mutex;
 use cortex_m_rt::entry;
+use critical_section::Mutex;
 use panic_rtt_target as _;
 use rtt_target::{rprintln, rtt_init_print};
 use va108xx_hal::{
@ -83,11 +83,12 @@ fn main() -> ! {
        }
    }
    loop {
-        let current_ms = cortex_m::interrupt::free(|cs| MS_COUNTER.borrow(cs).get());
+        let current_ms = critical_section::with(|cs| MS_COUNTER.borrow(cs).get());
        if current_ms - last_ms >= 1000 {
-            last_ms = current_ms;
+            // To prevent drift.
+            last_ms += 1000;
            rprintln!("MS counter: {}", current_ms);
-            let second = cortex_m::interrupt::free(|cs| SEC_COUNTER.borrow(cs).get());
+            let second = critical_section::with(|cs| SEC_COUNTER.borrow(cs).get());
            rprintln!("Second counter: {}", second);
        }
        cortex_m::asm::delay(10000);
@ -110,7 +111,7 @@ fn OC0() {
 #[interrupt]
 #[allow(non_snake_case)]
 fn OC1() {
-    cortex_m::interrupt::free(|cs| {
+    critical_section::with(|cs| {
        let mut sec = SEC_COUNTER.borrow(cs).get();
        sec += 1;
        SEC_COUNTER.borrow(cs).set(sec);
--- a/va108xx-hal/CHANGELOG.md
+++ b/va108xx-hal/CHANGELOG.md
@ -6,6 +6,20 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).

+## [unreleased]
+
+## Changed
+
+- Improves `CascardSource` handling and general API when chosing cascade sources.
+- Replaced `utility::unmask_irq` by `enable_interrupt` and `disable_interrupt` API.
+- Improve and fix SPI abstractions. Add new low level interface. The primary SPI constructor now
+  only expects a configuration structure and the transfer configuration needs to be applied in a
+  separate step.
+
+## Fixes
+
+- Fixes for SPI peripheral: Flush implementation was incorrect and should now flush properly.
+
 ## [v0.7.0] 2024-07-04

 - Replace `uarta` and `uartb` `Uart` constructors by `new` constructor
--- a/va108xx-hal/Cargo.toml
+++ b/va108xx-hal/Cargo.toml
@ -19,7 +19,7 @@ embedded-hal-nb = "1"
 embedded-io = "0.6"
 fugit = "0.3"
 typenum = "1"
-defmt = { version = "0.3", optional = true }
+critical-section = "1"
 delegate = "0.12"

 [dependencies.va108xx]
@ -38,9 +38,14 @@ default-features = false
 version = "1.14"
 default-features = false

+[dependencies.defmt]
+version = "0.3"
+optional = true
+
 [features]
 default = ["rt"]
 rt = ["va108xx/rt"]
+defmt = ["dep:defmt", "fugit/defmt"]

 [package.metadata.docs.rs]
 all-features = true
--- a/va108xx-hal/src/lib.rs
+++ b/va108xx-hal/src/lib.rs
@ -15,7 +15,6 @@ pub mod time;
 pub mod timer;
 pub mod typelevel;
 pub mod uart;
-pub mod utility;

 #[derive(Debug, Eq, Copy, Clone, PartialEq)]
 pub enum FunSel {
@ -98,3 +97,21 @@ pub fn port_mux(
        }
    }
 }
+
+/// Enable a specific interrupt using the NVIC peripheral.
+///
+/// # Safety
+///
+/// This function is `unsafe` because it can break mask-based critical sections.
+#[inline]
+pub unsafe fn enable_interrupt(irq: pac::Interrupt) {
+    unsafe {
+        cortex_m::peripheral::NVIC::unmask(irq);
+    }
+}
+
+/// Disable a specific interrupt using the NVIC peripheral.
+#[inline]
+pub fn disable_interrupt(irq: pac::Interrupt) {
+    cortex_m::peripheral::NVIC::mask(irq);
+}
--- a/va108xx-hal/src/spi.rs
+++ b/va108xx-hal/src/spi.rs
--- a/va108xx-hal/src/timer.rs
+++ b/va108xx-hal/src/timer.rs
@ -7,6 +7,7 @@
 pub use crate::IrqCfg;
 use crate::{
    clock::{enable_peripheral_clock, PeripheralClocks},
+    enable_interrupt,
    gpio::{
        AltFunc1, AltFunc2, AltFunc3, DynPinId, Pin, PinId, PA0, PA1, PA10, PA11, PA12, PA13, PA14,
        PA15, PA2, PA24, PA25, PA26, PA27, PA28, PA29, PA3, PA30, PA31, PA4, PA5, PA6, PA7, PA8,
@ -17,10 +18,9 @@ use crate::{
    time::Hertz,
    timer,
    typelevel::Sealed,
-    utility::unmask_irq,
 };
 use core::cell::Cell;
-use cortex_m::interrupt::Mutex;
+use critical_section::Mutex;
 use fugit::RateExtU32;

 const IRQ_DST_NONE: u32 = 0xffffffff;
@ -72,25 +72,46 @@ pub enum CascadeSel {
    Csd2 = 2,
 }

+#[derive(Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub struct InvalidCascadeSourceId;
+
 /// The numbers are the base numbers for bundles like PORTA, PORTB or TIM
 #[derive(Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+#[repr(u8)]
 pub enum CascadeSource {
-    PortABase = 0,
-    PortBBase = 32,
-    TimBase = 64,
+    PortA(u8),
+    PortB(u8),
+    Tim(u8),
    RamSbe = 96,
    RamMbe = 97,
    RomSbe = 98,
    RomMbe = 99,
    Txev = 100,
-    ClockDividerBase = 120,
+    ClockDivider(u8),
 }

-#[derive(Debug, PartialEq, Eq)]
-pub enum TimerErrors {
-    Canceled,
-    /// Invalid input for Cascade source
-    InvalidCsdSourceInput,
+impl CascadeSource {
+    fn id(&self) -> Result<u8, InvalidCascadeSourceId> {
+        let port_check = |base: u8, id: u8, len: u8| {
+            if id > len - 1 {
+                return Err(InvalidCascadeSourceId);
+            }
+            Ok(base + id)
+        };
+        match self {
+            CascadeSource::PortA(id) => port_check(0, *id, 32),
+            CascadeSource::PortB(id) => port_check(32, *id, 32),
+            CascadeSource::Tim(id) => port_check(64, *id, 24),
+            CascadeSource::RamSbe => Ok(96),
+            CascadeSource::RamMbe => Ok(97),
+            CascadeSource::RomSbe => Ok(98),
+            CascadeSource::RomMbe => Ok(99),
+            CascadeSource::Txev => Ok(100),
+            CascadeSource::ClockDivider(id) => port_check(120, *id, 8),
+        }
+    }
 }

 //==================================================================================================
@ -360,89 +381,26 @@ pub struct CountDownTimer<TIM: ValidTim> {
    listening: bool,
 }

-fn enable_tim_clk(syscfg: &mut pac::Sysconfig, idx: u8) {
+#[inline(always)]
+pub fn enable_tim_clk(syscfg: &mut pac::Sysconfig, idx: u8) {
    syscfg
        .tim_clk_enable()
        .modify(|r, w| unsafe { w.bits(r.bits() | (1 << idx)) });
 }

+#[inline(always)]
+pub fn disable_tim_clk(syscfg: &mut pac::Sysconfig, idx: u8) {
+    syscfg
+        .tim_clk_enable()
+        .modify(|r, w| unsafe { w.bits(r.bits() & !(1 << idx)) });
+}
+
 unsafe impl<TIM: ValidTim> TimRegInterface for CountDownTimer<TIM> {
    fn tim_id(&self) -> u8 {
        TIM::TIM_ID
    }
 }

-macro_rules! csd_sel {
-    ($func_name:ident, $csd_reg:ident) => {
-        /// Configure the Cascade sources
-        pub fn $func_name(
-            &mut self,
-            src: CascadeSource,
-            id: Option<u8>,
-        ) -> Result<(), TimerErrors> {
-            let mut id_num = 0;
-            if let CascadeSource::PortABase
-            | CascadeSource::PortBBase
-            | CascadeSource::ClockDividerBase
-            | CascadeSource::TimBase = src
-            {
-                if id.is_none() {
-                    return Err(TimerErrors::InvalidCsdSourceInput);
-                }
-            }
-            if id.is_some() {
-                id_num = id.unwrap();
-            }
-            match src {
-                CascadeSource::PortABase => {
-                    if id_num > 55 {
-                        return Err(TimerErrors::InvalidCsdSourceInput);
-                    }
-                    self.tim.reg().$csd_reg().write(|w| unsafe {
-                        w.cassel().bits(CascadeSource::PortABase as u8 + id_num)
-                    });
-                    Ok(())
-                }
-                CascadeSource::PortBBase => {
-                    if id_num > 23 {
-                        return Err(TimerErrors::InvalidCsdSourceInput);
-                    }
-                    self.tim.reg().$csd_reg().write(|w| unsafe {
-                        w.cassel().bits(CascadeSource::PortBBase as u8 + id_num)
-                    });
-                    Ok(())
-                }
-                CascadeSource::TimBase => {
-                    if id_num > 23 {
-                        return Err(TimerErrors::InvalidCsdSourceInput);
-                    }
-                    self.tim.reg().$csd_reg().write(|w| unsafe {
-                        w.cassel().bits(CascadeSource::TimBase as u8 + id_num)
-                    });
-                    Ok(())
-                }
-                CascadeSource::ClockDividerBase => {
-                    if id_num > 7 {
-                        return Err(TimerErrors::InvalidCsdSourceInput);
-                    }
-                    self.tim.reg().cascade0().write(|w| unsafe {
-                        w.cassel()
-                            .bits(CascadeSource::ClockDividerBase as u8 + id_num)
-                    });
-                    Ok(())
-                }
-                _ => {
-                    self.tim
-                        .reg()
-                        .$csd_reg()
-                        .write(|w| unsafe { w.cassel().bits(src as u8) });
-                    Ok(())
-                }
-            }
-        }
-    };
-}
-
 impl<TIM: ValidTim> CountDownTimer<TIM> {
    /// Configures a TIM peripheral as a periodic count down timer
    pub fn new(syscfg: &mut pac::Sysconfig, sys_clk: impl Into<Hertz>, tim: TIM) -> Self {
@ -554,18 +512,18 @@ impl<TIM: ValidTim> CountDownTimer<TIM> {

    #[inline(always)]
    pub fn enable(&mut self) {
-        self.tim.reg().ctrl().modify(|_, w| w.enable().set_bit());
        if let Some(irq_cfg) = self.irq_cfg {
            self.enable_interrupt();
            if irq_cfg.enable {
-                unmask_irq(irq_cfg.irq);
+                unsafe { enable_interrupt(irq_cfg.irq) };
            }
        }
+        self.tim.reg().enable().write(|w| unsafe { w.bits(1) });
    }

    #[inline(always)]
    pub fn disable(&mut self) {
-        self.tim.reg().ctrl().modify(|_, w| w.enable().clear_bit());
+        self.tim.reg().enable().write(|w| unsafe { w.bits(0) });
    }

    /// Disable the counter, setting both enable and active bit to 0
@ -619,9 +577,32 @@ impl<TIM: ValidTim> CountDownTimer<TIM> {
        });
    }

-    csd_sel!(cascade_0_source, cascade0);
-    csd_sel!(cascade_1_source, cascade1);
-    csd_sel!(cascade_2_source, cascade2);
+    pub fn cascade_0_source(&mut self, src: CascadeSource) -> Result<(), InvalidCascadeSourceId> {
+        let id = src.id()?;
+        self.tim
+            .reg()
+            .cascade0()
+            .write(|w| unsafe { w.cassel().bits(id) });
+        Ok(())
+    }
+
+    pub fn cascade_1_source(&mut self, src: CascadeSource) -> Result<(), InvalidCascadeSourceId> {
+        let id = src.id()?;
+        self.tim
+            .reg()
+            .cascade1()
+            .write(|w| unsafe { w.cassel().bits(id) });
+        Ok(())
+    }
+
+    pub fn cascade_2_source(&mut self, src: CascadeSource) -> Result<(), InvalidCascadeSourceId> {
+        let id = src.id()?;
+        self.tim
+            .reg()
+            .cascade2()
+            .write(|w| unsafe { w.cassel().bits(id) });
+        Ok(())
+    }

    pub fn curr_freq(&self) -> Hertz {
        self.curr_freq
@ -656,12 +637,13 @@ impl<TIM: ValidTim> CountDownTimer<TIM> {
        }
    }

-    pub fn cancel(&mut self) -> Result<(), TimerErrors> {
+    /// Returns [false] if the timer was not active, and true otherwise.
+    pub fn cancel(&mut self) -> bool {
        if !self.tim.reg().ctrl().read().enable().bit_is_set() {
-            return Err(TimerErrors::Canceled);
+            return false;
        }
        self.tim.reg().ctrl().write(|w| w.enable().clear_bit());
-        Ok(())
+        true
    }
 }

@ -747,7 +729,7 @@ pub fn set_up_ms_delay_provider<TIM: ValidTim>(
 /// This function can be called in a specified interrupt handler to increment
 /// the MS counter
 pub fn default_ms_irq_handler() {
-    cortex_m::interrupt::free(|cs| {
+    critical_section::with(|cs| {
        let mut ms = MS_COUNTER.borrow(cs).get();
        ms += 1;
        MS_COUNTER.borrow(cs).set(ms);
@ -756,7 +738,7 @@ pub fn default_ms_irq_handler() {

 /// Get the current MS tick count
 pub fn get_ms_ticks() -> u32 {
-    cortex_m::interrupt::free(|cs| MS_COUNTER.borrow(cs).get())
+    critical_section::with(|cs| MS_COUNTER.borrow(cs).get())
 }

 //==================================================================================================
--- a/va108xx-hal/src/uart.rs
+++ b/va108xx-hal/src/uart.rs
@ -3,7 +3,7 @@
 //! ## Examples
 //!
 //! - [UART simple example](https://egit.irs.uni-stuttgart.de/rust/va108xx-rs/src/branch/main/examples/simple/examples/uart.rs)
-//! - [UART with IRQ and RTIC](https://egit.irs.uni-stuttgart.de/rust/va108xx-rs/src/branch/main/examples/simple/examples/uart-irq-rtic.rs)
+//! - [UART with IRQ and RTIC](https://egit.irs.uni-stuttgart.de/rust/va108xx-rs/src/branch/va108xx-update-package/examples/rtic/src/bin/uart-rtic.rs)
 use core::{marker::PhantomData, ops::Deref};
 use embedded_hal_nb::serial::Read;
 use fugit::RateExtU32;
@ -11,13 +11,13 @@ use fugit::RateExtU32;
 pub use crate::IrqCfg;
 use crate::{
    clock::{enable_peripheral_clock, PeripheralClocks},
+    enable_interrupt,
    gpio::pin::{
        AltFunc1, AltFunc2, AltFunc3, Pin, PA16, PA17, PA18, PA19, PA2, PA26, PA27, PA3, PA30,
        PA31, PA8, PA9, PB18, PB19, PB20, PB21, PB22, PB23, PB6, PB7, PB8, PB9,
    },
    pac::{self, uarta as uart_base},
    time::Hertz,
-    utility::unmask_irq,
    PeripheralSelect,
 };

@ -638,7 +638,7 @@ impl Instance for pac::Uartb {
    const PERIPH_SEL: PeripheralSelect = PeripheralSelect::Uart1;
 }

-impl<UART: Instance> UartWithIrqBase<UART> {
+impl<Uart: Instance> UartWithIrqBase<Uart> {
    fn init(self, sys_cfg: Option<&mut pac::Sysconfig>, irq_sel: Option<&mut pac::Irqsel>) -> Self {
        if let Some(sys_cfg) = sys_cfg {
            enable_peripheral_clock(sys_cfg, PeripheralClocks::Irqsel)
@ -646,7 +646,7 @@ impl<UART: Instance> UartWithIrqBase<UART> {
        if let Some(irq_sel) = irq_sel {
            if self.irq_info.irq_cfg.route {
                irq_sel
-                    .uart0(UART::IDX as usize)
+                    .uart0(Uart::IDX as usize)
                    .write(|w| unsafe { w.bits(self.irq_info.irq_cfg.irq as u32) });
            }
        }
@ -676,7 +676,9 @@ impl<UART: Instance> UartWithIrqBase<UART> {
        self.uart.enable_tx();
        self.enable_rx_irq_sources(enb_timeout_irq);
        if self.irq_info.irq_cfg.enable {
-            unmask_irq(self.irq_info.irq_cfg.irq);
+            unsafe {
+                enable_interrupt(self.irq_info.irq_cfg.irq);
+            }
        }
        Ok(())
    }
@ -839,7 +841,7 @@ impl<UART: Instance> UartWithIrqBase<UART> {
        self.irq_info.rx_len = 0;
    }

-    pub fn release(self) -> UART {
+    pub fn release(self) -> Uart {
        self.uart.release()
    }
 }
--- a/va108xx-hal/src/utility.rs
+++ b/va108xx-hal/src/utility.rs
@ -1,16 +0,0 @@
-//! # API for utility functions like the Error Detection and Correction (EDAC) block
-//!
-//! Some more information about the recommended scrub rates can be found on the
-//! [Vorago White Paper website](https://www.voragotech.com/resources) in the
-//! application note AN1212
-use crate::pac;
-
-/// Unmask and enable an IRQ with the given interrupt number
-///
-/// ## Safety
-///
-/// The unmask function can break mask-based critical sections
-#[inline]
-pub(crate) fn unmask_irq(irq: pac::Interrupt) {
-    unsafe { cortex_m::peripheral::NVIC::unmask(irq) };
-}
--- a/vorago-reb1/CHANGELOG.md
+++ b/vorago-reb1/CHANGELOG.md
@ -8,6 +8,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/).

 ## [unreleased]

+- Added M95M01 EEPROM module/API
+
 ## [v0.5.1] 2024-07-04

 - Update `va108xx-hal` dependency to v0.7.0
--- a/vorago-reb1/Cargo.toml
+++ b/vorago-reb1/Cargo.toml
@ -14,12 +14,15 @@ categories = ["aerospace", "embedded", "no-std", "hardware-support"]
 cortex-m = { version = "0.7", features = ["critical-section-single-core"] }
 cortex-m-rt = "0.7"
 embedded-hal = "1"
+nb = "1"
+bitfield = "0.17"

 [dependencies.max116xx-10bit]
 version = "0.3"

 [dependencies.va108xx-hal]
-version = "0.7"
+version = ">=0.7, <0.8"
+path = "../va108xx-hal"
 features = ["rt"]

 [features]
@ -28,20 +31,10 @@ rt = ["va108xx-hal/rt"]
 [dev-dependencies]
 panic-halt = "0.2"
 nb = "1"
-
-[dev-dependencies.rtt-target]
-version = "0.5"
-
-[dev-dependencies.panic-rtt-target]
-version = "0.1"
-
-[dev-dependencies.rtic]
-version = "2"
-features = ["thumbv6-backend"]
-
-[dev-dependencies.rtic-monotonics]
-version = "1"
-features = ["cortex-m-systick"]
+rtt-target = "0.5"
+panic-rtt-target = "0.1"
+embedded-hal-bus = "0.2"
+dummy-pin = "1"

 [package.metadata.docs.rs]
 all-features = true
--- a/vorago-reb1/examples/adxl343-accelerometer.rs
+++ b/vorago-reb1/examples/adxl343-accelerometer.rs
@ -5,15 +5,16 @@
 #![no_main]
 #![no_std]
 use cortex_m_rt::entry;
-use embedded_hal::spi::SpiBus;
+use embedded_hal::spi::{SpiBus, MODE_3};
 use embedded_hal::{delay::DelayNs, digital::OutputPin};
 use panic_rtt_target as _;
 use rtt_target::{rprintln, rtt_init_print};
+use va108xx_hal::spi::SpiClkConfig;
 use va108xx_hal::{
    gpio::PinsA,
    pac,
    prelude::*,
-    spi::{Spi, SpiConfig, TransferConfig},
+    spi::{Spi, SpiConfig},
    timer::set_up_ms_delay_provider,
 };

@ -31,7 +32,6 @@ fn main() -> ! {
    let mut dp = pac::Peripherals::take().unwrap();
    let mut delay = set_up_ms_delay_provider(&mut dp.sysconfig, 50.MHz(), dp.tim0);
    let pinsa = PinsA::new(&mut dp.sysconfig, None, dp.porta);
-    let spi_cfg = SpiConfig::default();
    let (sck, mosi, miso) = (
        pinsa.pa20.into_funsel_2(),
        pinsa.pa19.into_funsel_2(),
@ -45,21 +45,20 @@ fn main() -> ! {
        .set_high()
        .expect("Setting ADC chip select high failed");

-    let transfer_cfg = TransferConfig::new(
-        1.MHz(),
-        embedded_hal::spi::MODE_3,
-        Some(cs_pin),
-        false,
-        true,
-    );
+    let spi_cfg = SpiConfig::default()
+        .clk_cfg(
+            SpiClkConfig::from_clk(50.MHz(), 1.MHz()).expect("creating SPI clock config failed"),
+        )
+        .mode(MODE_3)
+        .slave_output_disable(true);
    let mut spi = Spi::new(
        &mut dp.sysconfig,
        50.MHz(),
        dp.spib,
        (sck, miso, mosi),
        spi_cfg,
-        Some(&transfer_cfg.downgrade()),
    );
+    spi.cfg_hw_cs_with_pin(&cs_pin);

    let mut tx_rx_buf: [u8; 3] = [0; 3];
    tx_rx_buf[0] = READ_MASK | DEVID_REG;
--- a/vorago-reb1/examples/max11619-adc.rs
+++ b/vorago-reb1/examples/max11619-adc.rs
@ -9,19 +9,19 @@ use core::convert::Infallible;

 use cortex_m_rt::entry;
 use embedded_hal::digital::OutputPin;
-use embedded_hal::spi::{SpiBus, SpiDevice};
+use embedded_hal::spi::{SpiBus, SpiDevice, MODE_0};
 use embedded_hal::{delay::DelayNs, spi};
 use max116xx_10bit::VoltageRefMode;
 use max116xx_10bit::{AveragingConversions, AveragingResults};
 use panic_rtt_target as _;
 use rtt_target::{rprintln, rtt_init_print};
-use va108xx_hal::spi::{NoneT, OptionalHwCs};
+use va108xx_hal::spi::{OptionalHwCs, SpiClkConfig};
 use va108xx_hal::timer::CountDownTimer;
 use va108xx_hal::{
    gpio::PinsA,
    pac::{self, interrupt},
    prelude::*,
-    spi::{Spi, SpiBase, SpiConfig, TransferConfig},
+    spi::{Spi, SpiBase, SpiConfig},
    timer::{default_ms_irq_handler, set_up_ms_tick, DelayMs, IrqCfg},
 };
 use va108xx_hal::{port_mux, FunSel, PortSel};
@ -103,6 +103,8 @@ impl<Delay: DelayNs, HwCs: OptionalHwCs<pac::Spib>> SpiDevice for SpiWithHwCs<De
    }
 }

+const SYS_CLK: Hertz = Hertz::from_raw(50_000_000);
+
 #[entry]
 fn main() -> ! {
    rtt_init_print!();
@ -113,7 +115,7 @@ fn main() -> ! {
        IrqCfg::new(pac::Interrupt::OC0, true, true),
        &mut dp.sysconfig,
        Some(&mut dp.irqsel),
-        50.MHz(),
+        SYS_CLK,
        dp.tim0,
    );
    let delay = DelayMs::new(tim0).unwrap();
@ -122,7 +124,10 @@ fn main() -> ! {
    }

    let pinsa = PinsA::new(&mut dp.sysconfig, None, dp.porta);
-    let spi_cfg = SpiConfig::default();
+    let spi_cfg = SpiConfig::default()
+        .clk_cfg(SpiClkConfig::from_clk(SYS_CLK, 3.MHz()).unwrap())
+        .mode(MODE_0)
+        .blockmode(true);
    let (sck, mosi, miso) = (
        pinsa.pa20.into_funsel_2(),
        pinsa.pa19.into_funsel_2(),
@ -141,14 +146,12 @@ fn main() -> ! {
        .set_high()
        .expect("Setting accelerometer chip select high failed");

-    let transfer_cfg = TransferConfig::<NoneT>::new(3.MHz(), spi::MODE_0, None, true, false);
    let spi = Spi::new(
        &mut dp.sysconfig,
        50.MHz(),
        dp.spib,
        (sck, miso, mosi),
        spi_cfg,
-        Some(&transfer_cfg.downgrade()),
    )
    .downgrade();
    let delay_provider = CountDownTimer::new(&mut dp.sysconfig, 50.MHz(), dp.tim1);
--- a/vorago-reb1/examples/nvm.rs
+++ b/vorago-reb1/examples/nvm.rs
@ -0,0 +1,64 @@
+//! Example application which interfaces with the boot EEPROM.
+#![no_main]
+#![no_std]
+
+use cortex_m_rt::entry;
+use embedded_hal::delay::DelayNs;
+use panic_rtt_target as _;
+use rtt_target::{rprintln, rtt_init_print};
+use va108xx_hal::{pac, pwm::CountDownTimer, time::Hertz};
+use vorago_reb1::m95m01::M95M01;
+
+const CLOCK_FREQ: Hertz = Hertz::from_raw(50_000_000);
+
+#[entry]
+fn main() -> ! {
+    rtt_init_print!();
+    rprintln!("-- VA108XX REB1 NVM example --");
+
+    let mut dp = pac::Peripherals::take().unwrap();
+
+    let mut timer = CountDownTimer::new(&mut dp.sysconfig, CLOCK_FREQ, dp.tim0);
+    let mut nvm = M95M01::new(&mut dp.sysconfig, CLOCK_FREQ, dp.spic);
+    let status_reg = nvm.read_status_reg().expect("reading status reg failed");
+    if status_reg.zero_segment() == 0b111 {
+        panic!("status register unexpected values");
+    }
+
+    let mut orig_content: [u8; 16] = [0; 16];
+    let mut read_buf: [u8; 16] = [0; 16];
+    let write_buf: [u8; 16] = [0; 16];
+    for (idx, val) in read_buf.iter_mut().enumerate() {
+        *val = idx as u8;
+    }
+    nvm.read(0x4000, &mut orig_content).unwrap();
+
+    // One byte write and read.
+    nvm.write(0x4000, &write_buf[0..1]).unwrap();
+    nvm.read(0x4000, &mut read_buf[0..1]).unwrap();
+    assert_eq!(write_buf[0], read_buf[0]);
+    read_buf.fill(0);
+
+    // Four bytes write and read.
+    nvm.write(0x4000, &write_buf[0..4]).unwrap();
+    nvm.read(0x4000, &mut read_buf[0..4]).unwrap();
+    assert_eq!(&read_buf[0..4], &write_buf[0..4]);
+    read_buf.fill(0);
+
+    // Full sixteen bytes
+    nvm.write(0x4000, &write_buf).unwrap();
+    nvm.read(0x4000, &mut read_buf).unwrap();
+    assert_eq!(&read_buf, &write_buf);
+    read_buf.fill(0);
+
+    // 3 bytes
+    nvm.write(0x4000, &write_buf[0..3]).unwrap();
+    nvm.read(0x4000, &mut read_buf[0..3]).unwrap();
+    assert_eq!(&read_buf[0..3], &write_buf[0..3]);
+
+    // Write back original content.
+    nvm.write(0x4000, &orig_content).unwrap();
+    loop {
+        timer.delay_ms(500);
+    }
+}
--- a/vorago-reb1/src/lib.rs
+++ b/vorago-reb1/src/lib.rs
@ -3,5 +3,6 @@

 pub mod button;
 pub mod leds;
+pub mod m95m01;
 pub mod max11619;
 pub mod temp_sensor;
--- a/vorago-reb1/src/m95m01.rs
+++ b/vorago-reb1/src/m95m01.rs
@ -0,0 +1,172 @@
+//! Basic driver for the ST M95M01 EEPROM memory.
+//!
+//! This driver is used by the provided bootloader application for the REB1
+//! board. It provides a convenient wrapper around the HAL SPI to interface
+//! with the EEPROM memory of the REB1 board.
+//!
+//! # Example
+//!
+//! - [REB1 EEPROM example](https://egit.irs.uni-stuttgart.de/rust/va108xx-rs/src/branch/main/vorago-reb1/examples/nvm.rs)
+use core::convert::Infallible;
+use embedded_hal::spi::SpiBus;
+
+bitfield::bitfield! {
+    pub struct StatusReg(u8);
+    impl Debug;
+    u8;
+    pub status_register_write_protect, _: 7;
+    pub zero_segment, _: 6, 4;
+    pub block_protection_bits, set_block_protection_bits: 3, 2;
+    pub write_enable_latch, _: 1;
+    pub write_in_progress, _: 0;
+}
+
+// Registers.
+pub mod regs {
+    /// Write status register command.
+    pub const WRSR: u8 = 0x01;
+    // Write command.
+    pub const WRITE: u8 = 0x02;
+    // Read command.
+    pub const READ: u8 = 0x03;
+    /// Write disable command.
+    pub const WRDI: u8 = 0x04;
+    /// Read status register command.
+    pub const RDSR: u8 = 0x05;
+    /// Write enable command.
+    pub const WREN: u8 = 0x06;
+}
+
+use regs::*;
+use va108xx_hal::{
+    pac,
+    prelude::*,
+    spi::{RomMiso, RomMosi, RomSck, Spi, SpiConfig, BMSTART_BMSTOP_MASK},
+};
+
+pub type RomSpi = Spi<pac::Spic, (RomSck, RomMiso, RomMosi), u8>;
+
+/// Driver for the ST device M95M01 EEPROM memory.
+///
+/// Specialized for the requirements of the VA108XX MCUs.
+pub struct M95M01 {
+    pub spi: RomSpi,
+}
+
+impl M95M01 {
+    pub fn new(syscfg: &mut pac::Sysconfig, sys_clk: impl Into<Hertz>, spi: pac::Spic) -> Self {
+        let spi = RomSpi::new(
+            syscfg,
+            sys_clk,
+            spi,
+            (RomSck, RomMiso, RomMosi),
+            SpiConfig::default(),
+        );
+        let mut spi_dev = Self { spi };
+        spi_dev.clear_block_protection().unwrap();
+        spi_dev
+    }
+
+    pub fn release(mut self) -> pac::Spic {
+        self.set_block_protection().unwrap();
+        self.spi.release().0
+    }
+
+    // Wait until the write-in-progress state is cleared. This exposes a [nb] API, so this function
+    // will return [nb::Error::WouldBlock] if the EEPROM is still busy.
+    pub fn writes_are_done(&mut self) -> nb::Result<(), Infallible> {
+        let rdsr = self.read_status_reg()?;
+        if rdsr.write_in_progress() {
+            return Err(nb::Error::WouldBlock);
+        }
+        Ok(())
+    }
+
+    pub fn read_status_reg(&mut self) -> Result<StatusReg, Infallible> {
+        let mut write_read: [u8; 2] = [regs::RDSR, 0x00];
+        self.spi.transfer_in_place(&mut write_read)?;
+        Ok(StatusReg(write_read[1]))
+    }
+
+    pub fn write_enable(&mut self) -> Result<(), Infallible> {
+        self.spi.write(&[regs::WREN])
+    }
+
+    pub fn clear_block_protection(&mut self) -> Result<(), Infallible> {
+        // Has to be written separately.
+        self.write_enable()?;
+        self.spi.write(&[WRSR, 0x00])
+    }
+
+    pub fn set_block_protection(&mut self) -> Result<(), Infallible> {
+        let mut reg = StatusReg(0);
+        reg.set_block_protection_bits(0b11);
+        self.write_enable()?;
+        self.spi.write(&[WRSR, reg.0])
+    }
+
+    fn common_init_write_and_read(&mut self, address: u32, reg: u8) -> Result<(), Infallible> {
+        nb::block!(self.writes_are_done())?;
+        self.spi.flush()?;
+        if reg == WRITE {
+            self.write_enable()?;
+            self.spi.write_fifo_unchecked(WRITE as u32);
+        } else {
+            self.spi.write_fifo_unchecked(READ as u32);
+        }
+        self.spi.write_fifo_unchecked((address >> 16) & 0xff);
+        self.spi.write_fifo_unchecked((address >> 8) & 0xff);
+        self.spi.write_fifo_unchecked(address & 0xff);
+        Ok(())
+    }
+
+    fn common_read(&mut self, address: u32) -> Result<(), Infallible> {
+        self.common_init_write_and_read(address, READ)?;
+        for _ in 0..4 {
+            // Pump the FIFO.
+            self.spi.write_fifo_unchecked(0);
+            // Ignore the first 4 bytes.
+            self.spi.read_fifo_unchecked();
+        }
+        Ok(())
+    }
+
+    pub fn write(&mut self, address: u32, data: &[u8]) -> Result<(), Infallible> {
+        self.common_init_write_and_read(address, WRITE)?;
+        for val in data.iter().take(data.len() - 1) {
+            nb::block!(self.spi.write_fifo(*val as u32))?;
+            self.spi.read_fifo_unchecked();
+        }
+        nb::block!(self
+            .spi
+            .write_fifo(*data.last().unwrap() as u32 | BMSTART_BMSTOP_MASK))?;
+        self.spi.flush()?;
+        nb::block!(self.writes_are_done())?;
+        Ok(())
+    }
+
+    pub fn read(&mut self, address: u32, buf: &mut [u8]) -> Result<(), Infallible> {
+        self.common_read(address)?;
+        for val in buf.iter_mut() {
+            nb::block!(self.spi.write_fifo(0))?;
+            *val = (nb::block!(self.spi.read_fifo()).unwrap() & 0xff) as u8;
+        }
+        nb::block!(self.spi.write_fifo(BMSTART_BMSTOP_MASK))?;
+        self.spi.flush()?;
+        Ok(())
+    }
+
+    pub fn verify(&mut self, address: u32, data: &[u8]) -> Result<bool, Infallible> {
+        self.common_read(address)?;
+        for val in data.iter() {
+            nb::block!(self.spi.write_fifo(0))?;
+            let read_val = (nb::block!(self.spi.read_fifo()).unwrap() & 0xff) as u8;
+            if read_val != *val {
+                return Ok(false);
+            }
+        }
+        nb::block!(self.spi.write_fifo(BMSTART_BMSTOP_MASK))?;
+        self.spi.flush()?;
+        Ok(true)
+    }
+}
--- a/vorago-reb1/src/temp_sensor.rs
+++ b/vorago-reb1/src/temp_sensor.rs
@ -4,7 +4,7 @@
 //!
 //! ## Examples
 //!
-//! - [Temperature Sensor example](https://egit.irs.uni-stuttgart.de/rust/va108xx-rs/src/branch/main/vorago-reb1/examples/adt75-temp-sensor.rs
+//! - [Temperature Sensor example](https://egit.irs.uni-stuttgart.de/rust/va108xx-rs/src/branch/main/vorago-reb1/examples/adt75-temp-sensor.rs)
 use embedded_hal::i2c::{I2c, SevenBitAddress};
 use va108xx_hal::{
    i2c::{Error, I2cMaster, I2cSpeed, InitError, MasterConfig},
--- a/vscode/launch.json
+++ b/vscode/launch.json
@ -20,7 +20,7 @@
            "runToEntryPoint": "main",
            "rttConfig": {
                "enabled": true,
-                "address": "0x10000000",
+                "address": "auto",
                "decoders": [
                    {
                        "port": 0,
@ -44,7 +44,7 @@
            "runToEntryPoint": "main",
            "rttConfig": {
                "enabled": true,
-                "address": "0x10000000",
+                "address": "auto",
                "decoders": [
                    {
                        "port": 0,
@ -68,7 +68,7 @@
            "runToEntryPoint": "main",
            "rttConfig": {
                "enabled": true,
-                "address": "0x10000000",
+                "address": "auto",
                "decoders": [
                    {
                        "port": 0,
@ -92,7 +92,7 @@
            "runToEntryPoint": "main",
            "rttConfig": {
                "enabled": true,
-                "address": "0x10000000",
+                "address": "auto",
                "decoders": [
                    {
                        "port": 0,
@ -116,7 +116,7 @@
            "runToEntryPoint": "main",
            "rttConfig": {
                "enabled": true,
-                "address": "0x10000000",
+                "address": "auto",
                "decoders": [
                    {
                        "port": 0,
@ -129,7 +129,7 @@
        {
            "type": "cortex-debug",
            "request": "launch",
-            "name": "Debug UART",
+            "name": "UART Example",
            "servertype": "jlink",
            "cwd": "${workspaceRoot}",
            "device": "Cortex-M0",
@ -140,7 +140,7 @@
            "runToEntryPoint": "main",
            "rttConfig": {
                "enabled": true,
-                "address": "0x10000000",
+                "address": "auto",
                "decoders": [
                    {
                        "port": 0,
@ -164,7 +164,7 @@
            "runToEntryPoint": "main",
            "rttConfig": {
                "enabled": true,
-                "address": "0x10000000",
+                "address": "auto",
                "decoders": [
                    {
                        "port": 0,
@ -188,7 +188,7 @@
            "runToEntryPoint": "main",
            "rttConfig": {
                "enabled": true,
-                "address": "0x10000000",
+                "address": "auto",
                "decoders": [
                    {
                        "port": 0,
@ -212,7 +212,7 @@
            "runToEntryPoint": "main",
            "rttConfig": {
                "enabled": true,
-                "address": "0x10000000",
+                "address": "auto",
                "decoders": [
                    {
                        "port": 0,
@ -236,7 +236,7 @@
            "runToEntryPoint": "main",
            "rttConfig": {
                "enabled": true,
-                "address": "0x10000000",
+                "address": "auto",
                "decoders": [
                    {
                        "port": 0,
@ -284,7 +284,7 @@
            "runToEntryPoint": "main",
            "rttConfig": {
                "enabled": true,
-                "address": "0x10000000",
+                "address": "auto",
                "decoders": [
                    {
                        "port": 0,
@ -321,7 +321,7 @@
            "runToEntryPoint": "main",
            "rttConfig": {
                "enabled": true,
-                "address": "0x10000000",
+                "address": "auto",
                "decoders": [
                    {
                        "port": 0,
@ -340,12 +340,84 @@
            "device": "Cortex-M0",
            "svdFile": "./va108xx/svd/va108xx.svd.patched",
            "preLaunchTask": "rust: cargo build uart irq",
-            "executable": "${workspaceFolder}/target/thumbv6m-none-eabi/debug/examples/uart-irq-rtic",
+            "executable": "${workspaceFolder}/target/thumbv6m-none-eabi/debug/uart-rtic",
            "interface": "jtag",
            "runToEntryPoint": "main",
            "rttConfig": {
                "enabled": true,
-                "address": "0x10000000",
+                "address": "auto",
+                "decoders": [
+                    {
+                        "port": 0,
+                        "timestamp": true,
+                        "type": "console"
+                    }
+                ]
+            }
+        },
+        {
+            "type": "cortex-debug",
+            "request": "launch",
+            "name": "REB1 NVM Example",
+            "servertype": "jlink",
+            "cwd": "${workspaceRoot}",
+            "device": "Cortex-M0",
+            "svdFile": "./va108xx/svd/va108xx.svd.patched",
+            "preLaunchTask": "reb1-nvm",
+            "executable": "${workspaceFolder}/target/thumbv6m-none-eabi/debug/examples/nvm",
+            "interface": "jtag",
+            "runToEntryPoint": "main",
+            "rttConfig": {
+                "enabled": true,
+                "address": "auto",
+                "decoders": [
+                    {
+                        "port": 0,
+                        "timestamp": true,
+                        "type": "console"
+                    }
+                ]
+            }
+        },
+        {
+            "type": "cortex-debug",
+            "request": "launch",
+            "name": "RTIC Example",
+            "servertype": "jlink",
+            "cwd": "${workspaceRoot}",
+            "device": "Cortex-M0",
+            "svdFile": "./va108xx/svd/va108xx.svd.patched",
+            "preLaunchTask": "rtic-example",
+            "executable": "${workspaceFolder}/target/thumbv6m-none-eabi/debug/rtic-example",
+            "interface": "jtag",
+            "runToEntryPoint": "main",
+            "rttConfig": {
+                "enabled": true,
+                "address": "auto",
+                "decoders": [
+                    {
+                        "port": 0,
+                        "timestamp": true,
+                        "type": "console"
+                    }
+                ]
+            }
+        },
+        {
+            "type": "cortex-debug",
+            "request": "launch",
+            "name": "Embassy Example",
+            "servertype": "jlink",
+            "cwd": "${workspaceRoot}",
+            "device": "Cortex-M0",
+            "svdFile": "./va108xx/svd/va108xx.svd.patched",
+            "preLaunchTask": "embassy-example",
+            "executable": "${workspaceFolder}/target/thumbv6m-none-eabi/debug/embassy-example",
+            "interface": "jtag",
+            "runToEntryPoint": "main",
+            "rttConfig": {
+                "enabled": true,
+                "address": "auto",
                "decoders": [
                    {
                        "port": 0,
--- a/vscode/tasks.json
+++ b/vscode/tasks.json
@ -67,8 +67,6 @@
            "command": "~/.cargo/bin/cargo", // note: full path to the cargo
            "args": [
                "build",
-                "-p",
-                "va108xx-hal",
                "--example",
                "uart",
            ],
@ -129,10 +127,8 @@
            "command": "~/.cargo/bin/cargo", // note: full path to the cargo
            "args": [
                "build",
-                "--example",
-                "uart-irq-rtic",
-                "--features",
-                "rt"
+                "--bin",
+                "uart-rtic",
            ],
            "group": {
                "kind": "build",
@ -158,8 +154,6 @@
            "command": "~/.cargo/bin/cargo", // note: full path to the cargo
            "args": [
                "build",
-                "-p",
-                "vorago-reb1",
                "--example",
                "blinky-leds",
            ],
@ -174,8 +168,6 @@
            "command": "~/.cargo/bin/cargo", // note: full path to the cargo
            "args": [
                "build",
-                "-p",
-                "vorago-reb1",
                "--example",
                "blinky-button-irq",
            ],
@ -190,8 +182,6 @@
            "command": "~/.cargo/bin/cargo", // note: full path to the cargo
            "args": [
                "build",
-                "-p",
-                "vorago-reb1",
                "--example",
                "adt75-temp-sensor",
            ],
@ -206,8 +196,6 @@
            "command": "~/.cargo/bin/cargo", // note: full path to the cargo
            "args": [
                "build",
-                "-p",
-                "vorago-reb1",
                "--example",
                "blinky-button-rtic",
            ],
@ -222,8 +210,6 @@
            "command": "~/.cargo/bin/cargo", // note: full path to the cargo
            "args": [
                "build",
-                "-p",
-                "vorago-reb1",
                "--example",
                "adxl343-accelerometer"
            ],
@ -238,8 +224,6 @@
            "command": "~/.cargo/bin/cargo", // note: full path to the cargo
            "args": [
                "build",
-                "-p",
-                "vorago-reb1",
                "--example",
                "max11619-adc",
            ],
@ -248,5 +232,39 @@
                "isDefault": true
            }
        },
+        {
+            "label": "reb1-nvm",
+            "type": "shell",
+            "command": "~/.cargo/bin/cargo", // note: full path to the cargo
+            "args": [
+                "build",
+                "--example",
+                "nvm",
+            ],
+            "group": {
+                "kind": "build",
+                "isDefault": true
+            }
+        },
+        {
+            "label": "rtic-example",
+            "type": "shell",
+            "command": "~/.cargo/bin/cargo", // note: full path to the cargo
+            "args": [
+                "build",
+                "--bin",
+                "rtic-example",
+            ],
+        },
+        {
+            "label": "embassy-example",
+            "type": "shell",
+            "command": "~/.cargo/bin/cargo", // note: full path to the cargo
+            "args": [
+                "build",
+                "--bin",
+                "embassy-example",
+            ],
+        },
    ]
 }