nordic-dev.net/embassy
2
0
Fork 0
mirror of https://github.com/embassy-rs/embassy.git synced 2024-11-22 14:53:03 +00:00
Code Issues Packages Projects Releases Wiki Activity

Add workaround for STM32 i2cv1 errata

Browse Source
This commit is contained in:
James Munns 2024-04-29 12:32:33 +02:00
parent 51a4a73323
commit 5ce3a6b61e
1 changed files with 26 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
embassy-stm32/src/i2c/v1.rs
View File

@ -48,6 +48,32 @@ impl<'d, T: Instance, M: PeriMode> I2c<'d, T, M> {
//reg.set_anfoff(false); //reg.set_anfoff(false);
}); });
// Errata: "Start cannot be generated after a misplaced Stop"
//
// > If a master generates a misplaced Stop on the bus (bus error)
// > while the microcontroller I2C peripheral attempts to switch to
// > Master mode by setting the START bit, the Start condition is
// > not properly generated.
//
// This also can occur with falsely detected STOP events, for example
// if the SDA line is shorted to low.
//
// The workaround for this is to trigger the SWRST line AFTER power is
// enabled, AFTER PE is disabled and BEFORE making any other configuration.
//
// It COULD be possible to apply this workaround at runtime, instead of
// only on initialization, however this would require detecting the timeout
// or BUSY lockup condition, and re-configuring the peripheral after reset.
//
// This presents as an ~infinite hang on read or write, as the START condition
// is never generated, meaning the start event is never generated.
T::regs().cr1().modify(|reg| {
reg.set_swrst(true);
});
T::regs().cr1().modify(|reg| {
reg.set_swrst(false);
});
let timings = Timings::new(T::frequency(), freq); let timings = Timings::new(T::frequency(), freq);
T::regs().cr2().modify(|reg| { T::regs().cr2().modify(|reg| {