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cpu/samd21:i2c: increase timeout in _start to facilitate SHT2x hold

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This commit is contained in:
Kees Bakker 2016-07-28 21:06:25 +02:00
parent bf4741d0d7
commit d509221e77
1 changed files with 16 additions and 8 deletions
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24
cpu/sam0_common/periph/i2c.c
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@ -48,7 +48,7 @@ static inline int _start(SercomI2cm *dev, uint8_t address, uint8_t rw_flag);
static inline int _write(SercomI2cm *dev, const uint8_t *data, int length);
static inline int _read(SercomI2cm *dev, uint8_t *data, int length);
static inline void _stop(SercomI2cm *dev);
static inline int _wait_for_response(SercomI2cm *dev);
static inline int _wait_for_response(SercomI2cm *dev, uint32_t max_timeout_counter);
/**
* @brief Array holding one pre-initialized mutex for each I2C device
@ -392,8 +392,15 @@ static int _start(SercomI2cm *dev, uint8_t address, uint8_t rw_flag)
dev->ADDR.reg = (address << 1) | rw_flag | (0 << SERCOM_I2CM_ADDR_HS_Pos);
/* Wait for response on bus. */
if (_wait_for_response(dev) < 0)
return -1;
if (rw_flag == I2C_FLAG_READ) {
/* Some devices (e.g. SHT2x) can hold the bus while preparing the reply */
if (_wait_for_response(dev, 100 * SAMD21_I2C_TIMEOUT) < 0)
return -1;
}
else {
if (_wait_for_response(dev, SAMD21_I2C_TIMEOUT) < 0)
return -1;
}
/* Check for address response error unless previous error is detected. */
/* Check for error and ignore bus-error; workaround for BUSSTATE
@ -437,7 +444,8 @@ static inline int _write(SercomI2cm *dev, const uint8_t *data, int length)
DEBUG("Written byte #%i to data reg, now waiting for DR to be empty again\n", buffer_counter);
dev->DATA.reg = data[buffer_counter++];
if (_wait_for_response(dev) < 0)
/* Wait for response on bus. */
if (_wait_for_response(dev, SAMD21_I2C_TIMEOUT) < 0)
return -1;
/* Check for NACK from slave. */
@ -469,8 +477,8 @@ static inline int _read(SercomI2cm *dev, uint8_t *data, int length)
/* Save data to buffer. */
data[count] = dev->DATA.reg;
/* Wait for response. */
if (_wait_for_response(dev) < 0)
/* Wait for response on bus. */
if (_wait_for_response(dev, SAMD21_I2C_TIMEOUT) < 0)
return -1;
count++;
@ -491,13 +499,13 @@ static inline void _stop(SercomI2cm *dev)
DEBUG("Stop sent\n");
}
static inline int _wait_for_response(SercomI2cm *dev)
static inline int _wait_for_response(SercomI2cm *dev, uint32_t max_timeout_counter)
{
uint32_t timeout_counter = 0;
DEBUG("Wait for response.\n");
while (!(dev->INTFLAG.reg & SERCOM_I2CM_INTFLAG_MB)
&& !(dev->INTFLAG.reg & SERCOM_I2CM_INTFLAG_SB)) {
if (++timeout_counter >= SAMD21_I2C_TIMEOUT) {
if (++timeout_counter >= max_timeout_counter) {
DEBUG("STATUS_ERR_TIMEOUT\n");
return -1;
}