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stm32f0xx-hal
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More rubost error handling for I2C 

Signed-off-by: Daniel Egger <daniel@eggers-club.de>
trying.tmp
Daniel Egger 4 years ago
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e3c8e6f1a5
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bc723e1437
2 changed files with 58 additions and 52 deletions
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  1. 4
      CHANGELOG.md
  2. 106
      src/i2c.rs

4
CHANGELOG.md
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@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
## [Unreleased]
### Added
- More robust error handling for I2C
## [v0.11.0] - 2019-01-04
### Added

106
src/i2c.rs
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@ -122,10 +122,10 @@ macro_rules! i2c {
// NOTE(unsafe) This executes only during initialisation
let rcc = unsafe { &(*crate::stm32::RCC::ptr()) };
/* Enable clock for I2C */
// Enable clock for I2C
rcc.$apbenr.modify(|_, w| w.$i2cXen().set_bit());
/* Reset I2C */
// Reset I2C
rcc.$apbrstr.modify(|_, w| w.$i2cXrst().set_bit());
rcc.$apbrstr.modify(|_, w| w.$i2cXrst().clear_bit());
I2c { i2c, pins }.i2c_init(speed)
@ -163,7 +163,7 @@ where
fn i2c_init(self: Self, speed: KiloHertz) -> Self {
use core::cmp;
/* Make sure the I2C unit is disabled so we can configure it */
// Make sure the I2C unit is disabled so we can configure it
self.i2c.cr1.modify(|_, w| w.pe().clear_bit());
// Calculate settings for I2C speed modes
@ -191,7 +191,7 @@ where
scldel = 3;
}
/* Enable I2C signal generator, and configure I2C for 400KHz full speed */
// Enable I2C signal generator, and configure I2C for 400KHz full speed
self.i2c.timingr.write(|w| {
w.presc()
.bits(presc)
@ -205,7 +205,7 @@ where
.bits(scll)
});
/* Enable the I2C processing */
// Enable the I2C processing
self.i2c.cr1.modify(|_, w| w.pe().set_bit());
self
@ -215,15 +215,9 @@ where
(self.i2c, self.pins)
}
fn send_byte(&self, byte: u8) -> Result<(), Error> {
/* Wait until we're ready for sending */
while self.i2c.isr.read().txis().bit_is_clear() {}
/* Push out a byte of data */
self.i2c.txdr.write(|w| unsafe { w.bits(u32::from(byte)) });
/* If we received a NACK, then this is an error */
if self.i2c.isr.read().nackf().bit_is_set() {
fn check_and_clear_error_flags(&self, isr: &crate::stm32::i2c1::isr::R) -> Result<(), Error> {
// If we received a NACK, then this is an error
if isr.nackf().bit_is_set() {
self.i2c
.icr
.write(|w| w.stopcf().set_bit().nackcf().set_bit());
@ -233,8 +227,28 @@ where
Ok(())
}
fn send_byte(&self, byte: u8) -> Result<(), Error> {
// Wait until we're ready for sending
while {
let isr = self.i2c.isr.read();
self.check_and_clear_error_flags(&isr)?;
isr.txis().bit_is_clear()
} {}
// Push out a byte of data
self.i2c.txdr.write(|w| unsafe { w.bits(u32::from(byte)) });
self.check_and_clear_error_flags(&self.i2c.isr.read())?;
Ok(())
}
fn recv_byte(&self) -> Result<u8, Error> {
while self.i2c.isr.read().rxne().bit_is_clear() {}
while {
let isr = self.i2c.isr.read();
self.check_and_clear_error_flags(&isr)?;
isr.rxne().bit_is_clear()
} {}
let value = self.i2c.rxdr.read().bits() as u8;
Ok(value)
}
@ -248,8 +262,7 @@ where
type Error = Error;
fn write_read(&mut self, addr: u8, bytes: &[u8], buffer: &mut [u8]) -> Result<(), Error> {
/* Set up current address, we're trying a "read" command and not going to set anything
* and make sure we end a non-NACKed read (i.e. if we found a device) properly */
// Set up current slave address for writing and disable autoending
self.i2c.cr2.modify(|_, w| {
w.sadd()
.bits(u16::from(addr) << 1)
@ -261,37 +274,29 @@ where
.clear_bit()
});
/* Send a START condition */
// Send a START condition
self.i2c.cr2.modify(|_, w| w.start().set_bit());
/* Wait until the transmit buffer is empty and there hasn't been either a NACK or STOP
* being received */
let mut isr;
// Wait until the transmit buffer is empty and there hasn't been any error condition
while {
isr = self.i2c.isr.read();
isr.txis().bit_is_clear()
&& isr.nackf().bit_is_clear()
&& isr.stopf().bit_is_clear()
&& isr.tc().bit_is_clear()
let isr = self.i2c.isr.read();
self.check_and_clear_error_flags(&isr)?;
isr.txis().bit_is_clear() && isr.tc().bit_is_clear()
} {}
/* If we received a NACK, then this is an error */
if isr.nackf().bit_is_set() {
self.i2c
.icr
.write(|w| w.stopcf().set_bit().nackcf().set_bit());
return Err(Error::NACK);
}
// Send out all individual bytes
for c in bytes {
self.send_byte(*c)?;
}
/* Wait until data was sent */
while self.i2c.isr.read().tc().bit_is_clear() {}
// Wait until data was sent
while {
let isr = self.i2c.isr.read();
self.check_and_clear_error_flags(&isr)?;
isr.tc().bit_is_clear()
} {}
/* Set up current address, we're trying a "read" command and not going to set anything
* and make sure we end a non-NACKed read (i.e. if we found a device) properly */
// Set up current address for reading
self.i2c.cr2.modify(|_, w| {
w.sadd()
.bits(u16::from(addr) << 1)
@ -301,21 +306,19 @@ where
.set_bit()
});
/* Send a START condition */
// Send another START condition
self.i2c.cr2.modify(|_, w| w.start().set_bit());
/* Send the autoend after setting the start to get a restart */
// Send the autoend after setting the start to get a restart
self.i2c.cr2.modify(|_, w| w.autoend().set_bit());
/* Read in all bytes */
// Now read in all bytes
for c in buffer.iter_mut() {
*c = self.recv_byte()?;
}
/* Clear flags if they somehow ended up set */
self.i2c
.icr
.write(|w| w.stopcf().set_bit().nackcf().set_bit());
// Check and clear flags if they somehow ended up set
self.check_and_clear_error_flags(&self.i2c.isr.read())?;
Ok(())
}
@ -329,8 +332,7 @@ where
type Error = Error;
fn write(&mut self, addr: u8, bytes: &[u8]) -> Result<(), Error> {
/* Set up current address, we're trying a "read" command and not going to set anything
* and make sure we end a non-NACKed read (i.e. if we found a device) properly */
// Set up current slave address for writing and enable autoending
self.i2c.cr2.modify(|_, w| {
w.sadd()
.bits(u16::from(addr) << 1)
@ -342,17 +344,17 @@ where
.set_bit()
});
/* Send a START condition */
// Send a START condition
self.i2c.cr2.modify(|_, w| w.start().set_bit());
// Send out all individual bytes
for c in bytes {
self.send_byte(*c)?;
}
/* Fallthrough is success */
self.i2c
.icr
.write(|w| w.stopcf().set_bit().nackcf().set_bit());
// Check and clear flags if they somehow ended up set
self.check_and_clear_error_flags(&self.i2c.isr.read())?;
Ok(())
}
}

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