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| author | Damien George <damien.p.george@gmail.com> | 2018-06-15 14:10:53 +1000 |
|---|---|---|
| committer | Damien George <damien.p.george@gmail.com> | 2018-06-15 14:10:53 +1000 |
| commit | bc5e8a2cb6f17bc5a9fec108a2421adc77f5cb3c (patch) | |
| tree | 95295651b19926ce35760e63e0dd37c7718e0500 | |
| parent | 37a7257affa5e1ad449d911797dfc4b9e46677b3 (diff) | |
stm32/i2c: Fix num_acks calculation in i2c_write for F0 and F7 MCU's.
Due to buffering of outgoing bytes on the I2C bus, detection of a NACK
using the ISR_NACKF flag needs to account for the case where ISR_NACKF
corresponds to the previous-to-previous byte.
| -rw-r--r-- | ports/stm32/i2c.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/ports/stm32/i2c.c b/ports/stm32/i2c.c index e0eea90ab..109b9418f 100644 --- a/ports/stm32/i2c.c +++ b/ports/stm32/i2c.c @@ -421,8 +421,13 @@ int i2c_write(i2c_t *i2c, const uint8_t *src, size_t len, size_t next_len) { if ((ret = i2c_wait_isr_set(i2c, I2C_ISR_TCR | I2C_ISR_TC | I2C_ISR_STOPF))) { return ret; } - if (i2c->ISR & I2C_ISR_NACKF) { + uint32_t isr = i2c->ISR; + if (isr & I2C_ISR_NACKF) { // Slave did not respond to byte so stop sending + if (!(isr & I2C_ISR_TXE)) { + // The TXDR is still full so the byte previous to that wasn't actually ACK'd + --num_acks; + } break; } ++num_acks; |