CHANGELOG.md

@@ -8,6 +8,10 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [unreleased]
 
+### Changed
+
+- SPI `transfer` implemenation update to handle size missmatch between read and write.
+
 ## [v0.1.0]
 
 Init commit.

src/gpio/mod.rs

@@ -1,7 +1,7 @@
 //! GPIO support module.
 use core::convert::Infallible;
 
-pub use crate::ioconfig::{regs::FunSel, FilterClkSel, FilterType};
+pub use crate::ioconfig::{FilterClkSel, FilterType, regs::FunSel};
 pub use embedded_hal::digital::PinState;
 pub use ll::{InterruptEdge, InterruptLevel, PinId, Port, Pull};
 

src/spi/mod.rs

@@ -860,21 +860,28 @@ where
         self.transfer_preparation(write)?;
         let mut current_read_idx = 0;
         let mut current_write_idx = self.initial_send_fifo_pumping_with_words(write);
+        let max_idx = core::cmp::max(read.len(), write.len());
         while current_read_idx < read.len() || current_write_idx < write.len() {
-            if current_write_idx < write.len() {
+            if current_write_idx < max_idx {
                 if current_write_idx == write.len() - 1 && self.bmstall {
                     nb::block!(
                         self.write_fifo(write[current_write_idx].into() | BMSTART_BMSTOP_MASK)
                     )?;
-                } else {
+                } else if current_write_idx < write.len() {
                     nb::block!(self.write_fifo(write[current_write_idx].into()))?;
+                } else {
+                    nb::block!(self.write_fifo(0))?;
                 }
                 current_write_idx += 1;
             }
+            if current_read_idx < max_idx {
                 if current_read_idx < read.len() {
                     read[current_read_idx] = (nb::block!(self.read_fifo())? & Word::MASK)
                         .try_into()
                         .unwrap();
+                } else {
+                    nb::block!(self.read_fifo()).unwrap();
+                }
                 current_read_idx += 1;
             }
         }