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va108xx-hal/src/i2c.rs

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//! API for the I2C peripheral
//!
//! ## Examples
//!
//! - [Blocking I2C example]()
use crate::{
clock::{enable_peripheral_clock, PeripheralClocks},
pac::{I2CA, I2CB, SYSCONFIG},
time::Hertz,
Sealed,
};
use core::marker::PhantomData;
use embedded_hal::blocking::i2c::{
2021-12-04 21:25:35 +01:00
Read, Write, WriteIter, WriteIterRead, WriteRead,
};
2021-12-04 21:25:35 +01:00
pub use embedded_hal::blocking::i2c::{SevenBitAddress, TenBitAddress};
//==================================================================================================
// Defintions
//==================================================================================================
#[derive(Debug, PartialEq, Copy, Clone)]
pub enum FifoEmptyMode {
Stall = 0,
EndTransaction = 1,
}
#[derive(Debug, PartialEq)]
pub enum Error {
InvalidTimingParams,
ArbitrationLost,
NackAddr,
/// Data not acknowledged in write operation
NackData,
/// Not enough data received in read operation
InsufficientDataReceived,
/// Number of bytes in transfer too large (larger than 0x7fe)
DataTooLarge,
WrongAddrMode,
}
#[derive(Debug, PartialEq, Copy, Clone)]
enum I2cCmd {
Start = 0b00,
Stop = 0b10,
StartWithStop = 0b11,
Cancel = 0b100,
}
#[derive(Debug, PartialEq, Copy, Clone)]
pub enum I2cSpeed {
Regular100khz = 0,
Fast400khz = 1,
}
#[derive(Debug, PartialEq)]
pub enum I2cDirection {
Send = 0,
Read = 1,
}
#[derive(Debug, PartialEq, Copy, Clone)]
pub enum I2cAddress {
Regular(u8),
TenBit(u16),
}
//==================================================================================================
// Config
//==================================================================================================
pub struct TrTfThighTlow(u8, u8, u8, u8);
pub struct TsuStoTsuStaThdStaTBuf(u8, u8, u8, u8);
pub struct TimingCfg {
// 4 bit max width
tr: u8,
// 4 bit max width
tf: u8,
// 4 bit max width
thigh: u8,
// 4 bit max width
tlow: u8,
// 4 bit max width
tsu_sto: u8,
// 4 bit max width
tsu_sta: u8,
// 4 bit max width
thd_sta: u8,
// 4 bit max width
tbuf: u8,
}
impl TimingCfg {
pub fn new(
first_16_bits: TrTfThighTlow,
second_16_bits: TsuStoTsuStaThdStaTBuf,
) -> Result<Self, Error> {
if first_16_bits.0 > 0xf
|| first_16_bits.1 > 0xf
|| first_16_bits.2 > 0xf
|| first_16_bits.3 > 0xf
|| second_16_bits.0 > 0xf
|| second_16_bits.1 > 0xf
|| second_16_bits.2 > 0xf
|| second_16_bits.3 > 0xf
{
return Err(Error::InvalidTimingParams);
}
Ok(TimingCfg {
tr: first_16_bits.0,
tf: first_16_bits.1,
thigh: first_16_bits.2,
tlow: first_16_bits.3,
tsu_sto: second_16_bits.0,
tsu_sta: second_16_bits.1,
thd_sta: second_16_bits.2,
tbuf: second_16_bits.3,
})
}
pub fn reg(&self) -> u32 {
((self.tbuf as u32) << 28
| (self.thd_sta as u32) << 24
| (self.tsu_sta as u32) << 20
| (self.tsu_sto as u32) << 16
| (self.tlow as u32) << 12
| (self.thigh as u32) << 8
| (self.tf as u32) << 4
| (self.tr as u32)) as u32
}
}
impl Default for TimingCfg {
fn default() -> Self {
TimingCfg {
tr: 0x02,
tf: 0x01,
thigh: 0x08,
tlow: 0x09,
tsu_sto: 0x8,
tsu_sta: 0x0a,
thd_sta: 0x8,
tbuf: 0xa,
}
}
}
pub struct MasterConfig {
pub tx_fe_mode: FifoEmptyMode,
pub rx_fe_mode: FifoEmptyMode,
/// Enable the analog delay glitch filter
pub alg_filt: bool,
/// Enable the digital glitch filter
pub dlg_filt: bool,
pub tm_cfg: Option<TimingCfg>,
// Loopback mode
// lbm: bool,
}
impl Default for MasterConfig {
fn default() -> Self {
MasterConfig {
tx_fe_mode: FifoEmptyMode::Stall,
rx_fe_mode: FifoEmptyMode::Stall,
alg_filt: false,
dlg_filt: false,
tm_cfg: None,
}
}
}
impl Sealed for MasterConfig {}
pub struct SlaveConfig {
pub tx_fe_mode: FifoEmptyMode,
pub rx_fe_mode: FifoEmptyMode,
/// Maximum number of words before issuing a negative acknowledge.
/// Range should be 0 to 0x7fe. Setting the value to 0x7ff has the same effect as not setting
/// the enable bit since RXCOUNT stops counting at 0x7fe.
pub max_words: Option<usize>,
/// A received address is compared to the ADDRESS register (addr) using the address mask
/// (addr_mask). Those bits with a 1 in the address mask must match for there to be an address
/// match
pub addr: I2cAddress,
/// The default address mask will be 0x3ff to only allow full matches
pub addr_mask: Option<u16>,
/// Optionally specify a second I2C address the slave interface responds to
pub addr_b: Option<I2cAddress>,
pub addr_b_mask: Option<u16>,
}
impl SlaveConfig {
/// Build a default slave config given a specified slave address to respond to
pub fn new(addr: I2cAddress) -> Self {
SlaveConfig {
tx_fe_mode: FifoEmptyMode::Stall,
rx_fe_mode: FifoEmptyMode::Stall,
max_words: None,
addr,
addr_mask: None,
addr_b: None,
addr_b_mask: None,
}
}
}
impl Sealed for SlaveConfig {}
//==================================================================================================
// I2C Base
//==================================================================================================
pub struct I2cBase<I2C> {
i2c: I2C,
sys_clk: Hertz,
}
impl<I2C> I2cBase<I2C> {
#[inline]
fn unwrap_addr(addr: I2cAddress) -> (u16, u32) {
match addr {
I2cAddress::Regular(addr) => (addr as u16, 0 << 15),
I2cAddress::TenBit(addr) => (addr, 1 << 15),
}
}
}
macro_rules! i2c_base {
($($I2CX:ident: ($i2cx:ident, $clk_enb:path),)+) => {
$(
impl I2cBase<$I2CX> {
pub fn $i2cx(
i2c: $I2CX,
sys_clk: impl Into<Hertz> + Copy,
speed_mode: I2cSpeed,
ms_cfg: Option<&MasterConfig>,
sl_cfg: Option<&SlaveConfig>,
sys_cfg: Option<&mut SYSCONFIG>,
) -> Self {
if let Some(sys_cfg) = sys_cfg {
enable_peripheral_clock(sys_cfg, $clk_enb);
}
let mut i2c_base = I2cBase {
i2c,
sys_clk: sys_clk.into(),
};
if let Some(ms_cfg) = ms_cfg {
i2c_base.cfg_master(ms_cfg);
}
if let Some(sl_cfg) = sl_cfg {
i2c_base.cfg_slave(sl_cfg);
}
i2c_base.cfg_clk_scale(speed_mode);
i2c_base
}
fn cfg_master(&mut self, ms_cfg: &MasterConfig) {
let (txfemd, rxfemd) = match (ms_cfg.tx_fe_mode, ms_cfg.rx_fe_mode) {
(FifoEmptyMode::Stall, FifoEmptyMode::Stall) => (false, false),
(FifoEmptyMode::Stall, FifoEmptyMode::EndTransaction) => (false, true),
(FifoEmptyMode::EndTransaction, FifoEmptyMode::Stall) => (true, false),
(FifoEmptyMode::EndTransaction, FifoEmptyMode::EndTransaction) => (true, true),
};
self.i2c.ctrl.modify(|_, w| {
w.txfemd().bit(txfemd);
w.rxffmd().bit(rxfemd);
w.dlgfilter().bit(ms_cfg.dlg_filt);
w.algfilter().bit(ms_cfg.alg_filt)
});
if let Some(ref tm_cfg) = ms_cfg.tm_cfg {
self.i2c.tmconfig.write(|w| unsafe { w.bits(tm_cfg.reg()) });
}
self.i2c.fifo_clr.write(|w| {
w.rxfifo().set_bit();
w.txfifo().set_bit()
});
}
fn cfg_slave(&mut self, sl_cfg: &SlaveConfig) {
let (txfemd, rxfemd) = match (sl_cfg.tx_fe_mode, sl_cfg.rx_fe_mode) {
(FifoEmptyMode::Stall, FifoEmptyMode::Stall) => (false, false),
(FifoEmptyMode::Stall, FifoEmptyMode::EndTransaction) => (false, true),
(FifoEmptyMode::EndTransaction, FifoEmptyMode::Stall) => (true, false),
(FifoEmptyMode::EndTransaction, FifoEmptyMode::EndTransaction) => (true, true),
};
self.i2c.s0_ctrl.modify(|_, w| {
w.txfemd().bit(txfemd);
w.rxffmd().bit(rxfemd)
});
self.i2c.s0_fifo_clr.write(|w| {
w.rxfifo().set_bit();
w.txfifo().set_bit()
});
let max_words = sl_cfg.max_words;
if let Some(max_words) = max_words {
self.i2c
.s0_maxwords
.write(|w| unsafe { w.bits(1 << 31 | max_words as u32) });
}
let (addr, addr_mode_mask) = Self::unwrap_addr(sl_cfg.addr);
// The first bit is the read/write value. Normally, both read and write are matched
// using the RWMASK bit of the address mask register
self.i2c
.s0_address
.write(|w| unsafe { w.bits((addr << 1) as u32 | addr_mode_mask) });
if let Some(addr_mask) = sl_cfg.addr_mask {
self.i2c
.s0_addressmask
.write(|w| unsafe { w.bits((addr_mask << 1) as u32) });
}
if let Some(addr_b) = sl_cfg.addr_b {
let (addr, addr_mode_mask) = Self::unwrap_addr(addr_b);
self.i2c
.s0_addressb
.write(|w| unsafe { w.bits((addr << 1) as u32 | addr_mode_mask) })
}
if let Some(addr_b_mask) = sl_cfg.addr_b_mask {
self.i2c
.s0_addressmaskb
.write(|w| unsafe { w.bits((addr_b_mask << 1) as u32) })
}
}
#[inline]
pub fn filters(&mut self, digital_filt: bool, analog_filt: bool) {
self.i2c.ctrl.modify(|_, w| {
w.dlgfilter().bit(digital_filt);
w.algfilter().bit(analog_filt)
});
}
#[inline]
pub fn fifo_empty_mode(&mut self, rx: FifoEmptyMode, tx: FifoEmptyMode) {
self.i2c.ctrl.modify(|_, w| {
w.txfemd().bit(tx as u8 != 0);
w.rxffmd().bit(rx as u8 != 0)
});
}
fn calc_clk_div(&self, speed_mode: I2cSpeed) -> u8 {
if speed_mode == I2cSpeed::Regular100khz {
((self.sys_clk.0 / (u32::pow(10, 5) * 20)) - 1) as u8
} else {
(((10 * self.sys_clk.0) / u32::pow(10, 8)) - 1) as u8
}
}
/// Configures the clock scale for a given speed mode setting
pub fn cfg_clk_scale(&mut self, speed_mode: I2cSpeed) {
self.i2c.clkscale.write(|w| unsafe {
w.bits((speed_mode as u32) << 31 | self.calc_clk_div(speed_mode) as u32)
});
}
pub fn load_address(&mut self, addr: u16) {
// Load address
self.i2c
.address
.write(|w| unsafe { w.bits((addr << 1) as u32) });
}
#[inline]
fn stop_cmd(&mut self) {
self.i2c
.cmd
.write(|w| unsafe { w.bits(I2cCmd::Stop as u32) });
}
}
)+
}
}
// Unique mode to use the loopback functionality
// pub struct I2cLoopback<I2C> {
// i2c_base: I2cBase<I2C>,
// master_cfg: MasterConfig,
// slave_cfg: SlaveConfig,
// }
i2c_base!(
I2CA: (i2ca, PeripheralClocks::I2c0),
I2CB: (i2cb, PeripheralClocks::I2c1),
);
//==================================================================================================
// I2C Master
//==================================================================================================
pub struct I2cMaster<I2C, ADDR = SevenBitAddress> {
i2c_base: I2cBase<I2C>,
_addr: PhantomData<ADDR>,
}
macro_rules! i2c_master {
($($I2CX:ident: ($i2cx:ident, $clk_enb:path),)+) => {
$(
impl<ADDR> I2cMaster<$I2CX, ADDR> {
pub fn $i2cx(
i2c: $I2CX,
cfg: MasterConfig,
sys_clk: impl Into<Hertz> + Copy,
speed_mode: I2cSpeed,
sys_cfg: Option<&mut SYSCONFIG>,
) -> Self {
I2cMaster {
i2c_base: I2cBase::$i2cx(
i2c,
sys_clk,
speed_mode,
Some(&cfg),
None,
sys_cfg
),
_addr: PhantomData,
}
.enable_master()
}
#[inline]
pub fn cancel_transfer(&self) {
self.i2c_base
.i2c
.cmd
.write(|w| unsafe { w.bits(I2cCmd::Cancel as u32) });
}
#[inline]
pub fn clear_tx_fifo(&self) {
self.i2c_base.i2c.fifo_clr.write(|w| w.txfifo().set_bit());
}
#[inline]
pub fn clear_rx_fifo(&self) {
self.i2c_base.i2c.fifo_clr.write(|w| w.rxfifo().set_bit());
}
#[inline]
pub fn enable_master(self) -> Self {
self.i2c_base.i2c.ctrl.modify(|_, w| w.enable().set_bit());
self
}
#[inline]
pub fn disable_master(self) -> Self {
self.i2c_base.i2c.ctrl.modify(|_, w| w.enable().clear_bit());
self
}
#[inline(always)]
fn load_fifo(&self, word: u8) {
self.i2c_base
.i2c
.data
.write(|w| unsafe { w.bits(word as u32) });
}
#[inline(always)]
fn read_fifo(&self) -> u8 {
self.i2c_base.i2c.data.read().bits() as u8
}
fn error_handler_write(&mut self, init_cmd: &I2cCmd) {
self.clear_tx_fifo();
if *init_cmd == I2cCmd::Start {
self.i2c_base.stop_cmd()
}
}
fn write_base(
&mut self,
addr: I2cAddress,
init_cmd: I2cCmd,
bytes: impl IntoIterator<Item = u8>,
) -> Result<(), Error> {
let mut iter = bytes.into_iter();
// Load address
let (addr, addr_mode_bit) = I2cBase::<$I2CX>::unwrap_addr(addr);
self.i2c_base.i2c.address.write(|w| unsafe {
w.bits(I2cDirection::Send as u32 | (addr << 1) as u32 | addr_mode_bit)
});
self.i2c_base
.i2c
.cmd
.write(|w| unsafe { w.bits(init_cmd as u32) });
let mut load_if_next_available = || {
if let Some(next_byte) = iter.next() {
self.load_fifo(next_byte);
}
};
loop {
let status_reader = self.i2c_base.i2c.status.read();
if status_reader.arblost().bit_is_set() {
self.error_handler_write(&init_cmd);
return Err(Error::ArbitrationLost);
} else if status_reader.nackaddr().bit_is_set() {
self.error_handler_write(&init_cmd);
return Err(Error::NackAddr);
} else if status_reader.nackdata().bit_is_set() {
self.error_handler_write(&init_cmd);
return Err(Error::NackData);
} else if status_reader.idle().bit_is_set() {
return Ok(());
} else {
while !status_reader.txnfull().bit_is_set() {
load_if_next_available();
}
}
}
}
fn write_from_buffer(
&mut self,
init_cmd: I2cCmd,
addr: I2cAddress,
output: &[u8],
) -> Result<(), Error> {
let len = output.len();
// It should theoretically possible to transfer larger data sizes by tracking
// the number of sent words and setting it to 0x7fe as soon as only that many
// bytes are remaining. However, large transfer like this are not common. This
// feature will therefore not be supported for now.
if len > 0x7fe {
return Err(Error::DataTooLarge);
}
// Load number of words
self.i2c_base
.i2c
.words
.write(|w| unsafe { w.bits(len as u32) });
let mut bytes = output.iter();
// FIFO has a depth of 16. We load slightly above the trigger level
// but not all of it because the transaction might fail immediately
const FILL_DEPTH: usize = 12;
// load the FIFO
for _ in 0..core::cmp::min(FILL_DEPTH, len) {
self.load_fifo(*bytes.next().unwrap());
}
self.write_base(addr, init_cmd, output.iter().cloned())
}
fn load_from_iter(
&self, bytes: impl IntoIterator<Item = u8>
) -> impl IntoIterator<Item = u8> {
let mut iter = bytes.into_iter();
// FIFO has a depth of 16. We load slightly above the trigger level
// but not all of it because the transaction might fail immediately
const FILL_DEPTH: usize = 12;
// load the FIFO
for _ in 0..FILL_DEPTH {
if let Some(next_byte) = iter.next() {
self.load_fifo(next_byte);
} else {
break;
}
}
iter
}
fn read_internal(&mut self, addr: I2cAddress, buffer: &mut [u8]) -> Result<(), Error> {
let len = buffer.len();
// It should theoretically possible to transfer larger data sizes by tracking
// the number of sent words and setting it to 0x7fe as soon as only that many
// bytes are remaining. However, large transfer like this are not common. This
// feature will therefore not be supported for now.
if len > 0x7fe {
return Err(Error::DataTooLarge);
}
// Clear the receive FIFO
self.clear_rx_fifo();
// Load number of words
self.i2c_base
.i2c
.words
.write(|w| unsafe { w.bits(len as u32) });
let (addr, addr_mode_bit) = match addr {
I2cAddress::Regular(addr) => (addr as u16, 0 << 15),
I2cAddress::TenBit(addr) => (addr, 1 << 15),
};
// Load address
self.i2c_base.i2c.address.write(|w| unsafe {
w.bits(I2cDirection::Read as u32 | (addr << 1) as u32 | addr_mode_bit)
});
let mut buf_iter = buffer.iter_mut();
let mut read_bytes = 0;
// Start receive transfer
self.i2c_base
.i2c
.cmd
.write(|w| unsafe { w.bits(I2cCmd::StartWithStop as u32) });
let mut read_if_next_available = || {
if let Some(next_byte) = buf_iter.next() {
*next_byte = self.read_fifo();
}
};
loop {
let status_reader = self.i2c_base.i2c.status.read();
if status_reader.arblost().bit_is_set() {
self.clear_rx_fifo();
return Err(Error::ArbitrationLost);
} else if status_reader.nackaddr().bit_is_set() {
self.clear_rx_fifo();
return Err(Error::NackAddr);
} else if status_reader.idle().bit_is_set() {
if read_bytes != len {
return Err(Error::InsufficientDataReceived);
}
return Ok(());
} else if status_reader.rxnempty().bit_is_set() {
read_if_next_available();
read_bytes += 1;
}
}
}
}
//======================================================================================
// Embedded HAL I2C implementations
//======================================================================================
impl Write<SevenBitAddress> for I2cMaster<$I2CX, SevenBitAddress> {
type Error = Error;
fn write(&mut self, addr: u8, output: &[u8]) -> Result<(), Self::Error> {
self.write_from_buffer(I2cCmd::StartWithStop, I2cAddress::Regular(addr), output)
}
}
impl Write<TenBitAddress> for I2cMaster<$I2CX, TenBitAddress> {
type Error = Error;
fn write(&mut self, addr: u16, output: &[u8]) -> Result<(), Self::Error> {
self.write_from_buffer(I2cCmd::StartWithStop, I2cAddress::TenBit(addr), output)
}
}
impl Read<SevenBitAddress> for I2cMaster<$I2CX, SevenBitAddress> {
type Error = Error;
fn read(&mut self, address: u8, buffer: &mut [u8]) -> Result<(), Self::Error> {
self.read_internal(I2cAddress::Regular(address), buffer)
}
}
impl Read<TenBitAddress> for I2cMaster<$I2CX, TenBitAddress> {
type Error = Error;
fn read(&mut self, address: u16, buffer: &mut [u8]) -> Result<(), Self::Error> {
self.read_internal(I2cAddress::TenBit(address), buffer)
}
}
impl WriteRead<SevenBitAddress> for I2cMaster<$I2CX, SevenBitAddress> {
type Error = Error;
fn write_read(
&mut self,
address: u8,
bytes: &[u8],
buffer: &mut [u8],
) -> Result<(), Self::Error> {
let addr = I2cAddress::Regular(address);
self.write_from_buffer(I2cCmd::Start, addr, bytes)?;
self.read_internal(addr, buffer)
}
}
impl WriteRead<TenBitAddress> for I2cMaster<$I2CX, TenBitAddress> {
type Error = Error;
fn write_read(
&mut self,
address: u16,
bytes: &[u8],
buffer: &mut [u8],
) -> Result<(), Self::Error> {
let addr = I2cAddress::TenBit(address);
self.write_from_buffer(I2cCmd::Start, addr, bytes)?;
self.read_internal(addr, buffer)
}
}
impl WriteIter<SevenBitAddress> for I2cMaster<$I2CX, SevenBitAddress> {
type Error = Error;
fn write<B>(&mut self, address: u8, bytes: B) -> Result<(), Self::Error>
where
B: IntoIterator<Item = u8>,
{
let iter = self.load_from_iter(bytes);
self.write_base(I2cAddress::Regular(address), I2cCmd::Start, iter)
}
}
impl WriteIterRead<SevenBitAddress> for I2cMaster<$I2CX, SevenBitAddress> {
type Error = Error;
fn write_iter_read<B>(
&mut self,
address: u8,
bytes: B,
buffer: &mut [u8],
) -> Result<(), Self::Error>
where
B: IntoIterator<Item = u8>,
{
let iter = self.load_from_iter(bytes);
let addr = I2cAddress::Regular(address);
self.write_base(addr, I2cCmd::Start, iter)?;
self.read_internal(addr, buffer)
}
}
)+
}
}
i2c_master!(
I2CA: (i2ca, PeripheralClocks::I2c0),
I2CB: (i2cb, PeripheralClocks::I2c1),
);
//==================================================================================================
// I2C Slave
//==================================================================================================
pub struct I2cSlave<I2C, ADDR = SevenBitAddress> {
i2c_base: I2cBase<I2C>,
_addr: PhantomData<ADDR>,
}
macro_rules! i2c_slave {
($($I2CX:ident: ($i2cx:ident, $i2cx_slave:ident),)+) => {
$(
impl<ADDR> I2cSlave<$I2CX, ADDR> {
fn $i2cx_slave(
i2c: $I2CX,
cfg: SlaveConfig,
sys_clk: impl Into<Hertz> + Copy,
speed_mode: I2cSpeed,
sys_cfg: Option<&mut SYSCONFIG>,
) -> Self {
I2cSlave {
i2c_base: I2cBase::$i2cx(
i2c,
sys_clk,
speed_mode,
None,
Some(&cfg),
sys_cfg
),
_addr: PhantomData,
}
.enable_slave()
}
#[inline]
pub fn enable_slave(self) -> Self {
self.i2c_base
.i2c
.s0_ctrl
.modify(|_, w| w.enable().set_bit());
self
}
#[inline]
pub fn disable_slave(self) -> Self {
self.i2c_base
.i2c
.s0_ctrl
.modify(|_, w| w.enable().clear_bit());
self
}
#[inline(always)]
fn load_fifo(&self, word: u8) {
self.i2c_base
.i2c
.s0_data
.write(|w| unsafe { w.bits(word as u32) });
}
#[inline(always)]
fn read_fifo(&self) -> u8 {
self.i2c_base.i2c.s0_data.read().bits() as u8
}
#[inline]
fn clear_tx_fifo(&self) {
self.i2c_base
.i2c
.s0_fifo_clr
.write(|w| w.txfifo().set_bit());
}
#[inline]
fn clear_rx_fifo(&self) {
self.i2c_base
.i2c
.s0_fifo_clr
.write(|w| w.rxfifo().set_bit());
}
/// Get the last address that was matched by the slave control and the corresponding
/// master direction
pub fn last_address(&self) -> (I2cDirection, u32) {
let bits = self.i2c_base.i2c.s0_lastaddress.read().bits();
match bits & 0x01 {
0 => (I2cDirection::Send, bits >> 1),
1 => (I2cDirection::Read, bits >> 1),
_ => (I2cDirection::Send, bits >> 1),
}
}
pub fn write(&mut self, output: &[u8]) -> Result<(), Error> {
let len = output.len();
// It should theoretically possible to transfer larger data sizes by tracking
// the number of sent words and setting it to 0x7fe as soon as only that many
// bytes are remaining. However, large transfer like this are not common. This
// feature will therefore not be supported for now.
if len > 0x7fe {
return Err(Error::DataTooLarge);
}
let mut bytes = output.iter();
// FIFO has a depth of 16. We load slightly above the trigger level
// but not all of it because the transaction might fail immediately
const FILL_DEPTH: usize = 12;
// load the FIFO
for _ in 0..core::cmp::min(FILL_DEPTH, len) {
self.load_fifo(*bytes.next().unwrap());
}
let status_reader = self.i2c_base.i2c.s0_status.read();
let mut load_if_next_available = || {
if let Some(next_byte) = bytes.next() {
self.load_fifo(*next_byte);
}
};
loop {
if status_reader.nackdata().bit_is_set() {
self.clear_tx_fifo();
return Err(Error::NackData);
} else if status_reader.idle().bit_is_set() {
return Ok(());
} else {
while !status_reader.txnfull().bit_is_set() {
load_if_next_available();
}
}
}
}
pub fn read(&mut self, buffer: &mut [u8]) -> Result<(), Error> {
let len = buffer.len();
// It should theoretically possible to transfer larger data sizes by tracking
// the number of sent words and setting it to 0x7fe as soon as only that many
// bytes are remaining. However, large transfer like this are not common. This
// feature will therefore not be supported for now.
if len > 0x7fe {
return Err(Error::DataTooLarge);
}
// Clear the receive FIFO
self.clear_rx_fifo();
let mut buf_iter = buffer.iter_mut();
let mut read_bytes = 0;
let mut read_if_next_available = || {
if let Some(next_byte) = buf_iter.next() {
*next_byte = self.read_fifo();
}
};
loop {
let status_reader = self.i2c_base.i2c.s0_status.read();
if status_reader.idle().bit_is_set() {
if read_bytes != len {
return Err(Error::InsufficientDataReceived);
}
return Ok(());
} else if status_reader.rxnempty().bit_is_set() {
read_bytes += 1;
read_if_next_available();
}
}
}
}
impl I2cSlave<$I2CX, SevenBitAddress> {
/// Create a new I2C slave for seven bit addresses
///
/// Returns a [`Error::WrongAddrMode`] error if a ten bit address is passed
pub fn i2ca(
i2c: $I2CX,
cfg: SlaveConfig,
sys_clk: impl Into<Hertz> + Copy,
speed_mode: I2cSpeed,
sys_cfg: Option<&mut SYSCONFIG>,
) -> Result<Self, Error> {
if let I2cAddress::TenBit(_) = cfg.addr {
return Err(Error::WrongAddrMode);
}
Ok(Self::$i2cx_slave(i2c, cfg, sys_clk, speed_mode, sys_cfg))
}
}
impl I2cSlave<$I2CX, TenBitAddress> {
pub fn $i2cx(
i2c: $I2CX,
cfg: SlaveConfig,
sys_clk: impl Into<Hertz> + Copy,
speed_mode: I2cSpeed,
sys_cfg: Option<&mut SYSCONFIG>,
) -> Self {
Self::$i2cx_slave(i2c, cfg, sys_clk, speed_mode, sys_cfg)
}
}
)+
}
}
i2c_slave!(I2CA: (i2ca, i2ca_slave), I2CB: (i2cb, i2cb_slave),);