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Merge pull request #1872 from thomaseichinger/stm32f1-i2c-multibyte-fix

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cpu/stm32f1: fix i2c master read for N=2 and N>2 bytes
This commit is contained in:
Hauke Petersen 2014-10-30 23:24:00 +01:00
commit 56062b0f23
1 changed files with 10 additions and 5 deletions
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15
cpu/stm32f1/periph/i2c.c
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@ -161,7 +161,7 @@ int i2c_read_bytes(i2c_t dev, uint8_t address, char *data, int length)
DEBUG("Send Slave address and wait for ADDR == 1\n"); DEBUG("Send Slave address and wait for ADDR == 1\n");
_start(i2c, address, I2C_FLAG_READ); _start(i2c, address, I2C_FLAG_READ);
DEBUG("Set POS bit\n"); DEBUG("Set POS bit\n");
i2c->CR1 |= I2C_CR1_POS; i2c->CR1 |= (I2C_CR1_POS | I2C_CR1_ACK);
DEBUG("Crit block: Clear ADDR bit and clear ACK flag\n"); DEBUG("Crit block: Clear ADDR bit and clear ACK flag\n");
state = disableIRQ(); state = disableIRQ();
_clear_addr(i2c); _clear_addr(i2c);
@ -192,9 +192,9 @@ int i2c_read_bytes(i2c_t dev, uint8_t address, char *data, int length)
_start(i2c, address, I2C_FLAG_READ); _start(i2c, address, I2C_FLAG_READ);
_clear_addr(i2c); _clear_addr(i2c);
while (i < (length - 2)) { while (i < (length - 3)) {
DEBUG("Wait until byte was received\n"); DEBUG("Wait until byte was received\n");
while (!(i2c->SR1 & I2C_SR1_BTF)); while (!(i2c->SR1 & I2C_SR1_RXNE));
DEBUG("Copy byte from DR\n"); DEBUG("Copy byte from DR\n");
data[i++] = (char)i2c->DR; data[i++] = (char)i2c->DR;
} }
@ -205,12 +205,17 @@ int i2c_read_bytes(i2c_t dev, uint8_t address, char *data, int length)
DEBUG("Disable ACK\n"); DEBUG("Disable ACK\n");
i2c->CR1 &= ~(I2C_CR1_ACK); i2c->CR1 &= ~(I2C_CR1_ACK);
DEBUG("Crit block: set STOP and read second last byte\n"); DEBUG("Crit block: set STOP and read N-2 byte\n");
state = disableIRQ(); state = disableIRQ();
i2c->CR1 |= (I2C_CR1_STOP);
data[i++] = (char)i2c->DR; data[i++] = (char)i2c->DR;
i2c->CR1 |= (I2C_CR1_STOP);
restoreIRQ(state); restoreIRQ(state);
DEBUG("Read N-1 byte\n");
data[i++] = (char)i2c->DR;
while (!(i2c->SR1 & I2C_SR1_RXNE)); while (!(i2c->SR1 & I2C_SR1_RXNE));
DEBUG("Read last byte\n");
data[i++] = (char)i2c->DR; data[i++] = (char)i2c->DR;
DEBUG("wait for STOP bit to be cleared again\n"); DEBUG("wait for STOP bit to be cleared again\n");