I2C 'Wait until byte is transferred' loop

[ijager]

I was reading the i2c code since I want to implement it for another chip. Then I encountered the following loop in the send_byte function:

        // Wait until byte is transferred
        loop {
            let isr = self.i2c.isr.read();
            if isr.berr().bit_is_set() {
                self.i2c.icr.write(|w| w.berrcf().set_bit());
                return Err(Error::BusError);
            } else if isr.arlo().bit_is_set() {
                self.i2c.icr.write(|w| w.arlocf().set_bit());
                return Err(Error::ArbitrationLost);
            } else if isr.nackf().bit_is_set() {
                self.i2c.icr.write(|w| w.nackcf().set_bit());
                return Err(Error::Nack);
            }
            return Ok(());
        }

stm32l0xx-hal/src/i2c.rs

Line 188 in f3b3e82

// Wait until byte is transferred

This loop seems wrong as it only ever runs once. Guess it might still work in practice most of the time. I guess the idea was to wait for txe bit to clear like in two lines above?

stm32l0xx-hal/src/i2c.rs

Line 183 in f3b3e82

while self.i2c.isr.read().txe().bit_is_clear() {}

[dbrgn]

Most probably a duplicate of #77 and #76.

What version do you use? If master, does the commit before #76 was merged work? If you're using the released version, can you try master?

[dbrgn]

@ijager can you test whether it works with the changes in #87 (https://github.com/gfroerli/stm32l0xx-hal/tree/i2c-correct-mappings)?

# Cargo.toml
stm32l0xx-hal = { git = "https://github.com/gfroerli/stm32l0xx-hal/", branch = "i2c-correct-mappings", features = ["rt", "mcu-YOURMCU"] }