int i2c_read(i2c_t *obj, int address, char *data, int length, int stop)
{
I2C_TypeDef *i2c = (I2C_TypeDef *)(obj->i2c);
I2cHandle.Instance = (I2C_TypeDef *)(obj->i2c);
int timeout;
int count;
int value;
i2c_start(obj);
// Wait until SB flag is set
timeout = FLAG_TIMEOUT;
while (__HAL_I2C_GET_FLAG(&I2cHandle, I2C_FLAG_SB) == RESET) {
timeout--;
if (timeout == 0) {
return -1;
}
}
i2c->DR = I2C_7BIT_ADD_READ(address);
// Wait address is acknowledged
timeout = FLAG_TIMEOUT;
while (__HAL_I2C_GET_FLAG(&I2cHandle, I2C_FLAG_ADDR) == RESET) {
timeout--;
if (timeout == 0) {
return -1;
}
}
__HAL_I2C_CLEAR_ADDRFLAG(&I2cHandle);
// Read all bytes except last one
for (count = 0; count < (length - 1); count++) {
value = i2c_byte_read(obj, 0);
data[count] = (char)value;
}
// If not repeated start, send stop.
// Warning: must be done BEFORE the data is read.
if (stop) {
i2c_stop(obj);
}
// Read the last byte
value = i2c_byte_read(obj, 1);
data[count] = (char)value;
return length;
}
int I2C_Read(I2C_TypeDef* I2Cx, int address, char* data, int length, int stop){
uint16_t timeout;
int count, value;
I2C_Start(I2Cx);
// Wait until SB flag is set
timeout = FLAG_TIMEOUT;
while(I2C_GetFlagStatus(I2Cx, I2C_FLAG_SB) == RESET){
timeout--;
if(timeout == 0){
return -1;
}
}
I2Cx->DR = I2C_7BIT_ADD_READ(address);
// Wait address is acknowledged
timeout = FLAG_TIMEOUT;
while(I2C_GetFlagStatus(I2Cx, I2C_FLAG_ADDR) == RESET){
timeout--;
if(timeout == 0){
return -1;
}
}
__I2C_CLEAR_ADDRFLAG(I2Cx);
// Read all bytes except last one
for (count = 0; count < (length - 1); count++) {
value = I2C_ByteRead(I2Cx, 0);
data[count] = (char)value;
}
// If not repeated start, send stop.
// Warning: must be done BEFORE the data is read.
if (stop) {
I2C_Stop(I2Cx);
}
// Read the last byte
value = I2C_ByteRead(I2Cx, 1);
data[count] = (char)value;
return length;
}
// this function is based on STM code
int machine_hard_i2c_readfrom(mp_obj_base_t *self_in, uint16_t addr, uint8_t *dest, size_t len, bool stop) {
machine_hard_i2c_obj_t *self = (machine_hard_i2c_obj_t*)self_in;
I2C_HandleTypeDef *hi2c = self->pyb->i2c;
uint32_t Timeout = *self->timeout;
/* Init tickstart for timeout management*/
uint32_t tickstart = HAL_GetTick();
#if 0
// TODO: for multi-master, here we could wait for the bus to be free
// we'd need a flag to tell if we were in the middle of a set of transactions
// (ie didn't send a stop bit in the last call)
/* Wait until BUSY flag is reset */
if (!I2C_WaitOnFlagUntilTimeout(hi2c, I2C_FLAG_BUSY, SET, I2C_TIMEOUT_BUSY_FLAG, tickstart)) {
return -MP_EBUSY;
}
#endif
/* Check if the I2C is already enabled */
if ((hi2c->Instance->CR1 & I2C_CR1_PE) != I2C_CR1_PE) {
/* Enable I2C peripheral */
__HAL_I2C_ENABLE(hi2c);
}
/* Disable Pos */
hi2c->Instance->CR1 &= ~I2C_CR1_POS;
/* Enable Acknowledge */
hi2c->Instance->CR1 |= I2C_CR1_ACK;
/* Send Slave Address */
int ret = send_addr_byte(hi2c, I2C_7BIT_ADD_READ(addr << 1), Timeout, tickstart);
if (ret != 0) {
return ret;
}
if (len == 0U) {
/* Clear ADDR flag */
__HAL_I2C_CLEAR_ADDRFLAG(hi2c);
/* Generate Stop */
if (stop) {
hi2c->Instance->CR1 |= I2C_CR1_STOP;
}
} else if (len == 1U) {
/* Disable Acknowledge */
hi2c->Instance->CR1 &= ~I2C_CR1_ACK;
/* Clear ADDR flag */
__HAL_I2C_CLEAR_ADDRFLAG(hi2c);
/* Generate Stop */
if (stop) {
hi2c->Instance->CR1 |= I2C_CR1_STOP;
}
} else if (len == 2U) {
/* Disable Acknowledge */
hi2c->Instance->CR1 &= ~I2C_CR1_ACK;
/* Enable Pos */
hi2c->Instance->CR1 |= I2C_CR1_POS;
/* Clear ADDR flag */
__HAL_I2C_CLEAR_ADDRFLAG(hi2c);
} else {
/* Enable Acknowledge */
hi2c->Instance->CR1 |= I2C_CR1_ACK;
/* Clear ADDR flag */
__HAL_I2C_CLEAR_ADDRFLAG(hi2c);
}
while (len > 0U) {
if (len <= 3U) {
if (len == 1U) {
/* Wait until RXNE flag is set */
int ret = I2C_WaitOnRXNEFlagUntilTimeout(hi2c, Timeout, tickstart);
if (ret != 0) {
return ret;
}
/* Read data from DR */
*dest++ = hi2c->Instance->DR;
len--;
} else if (len == 2U) {
/* Wait until BTF flag is set */
if (!I2C_WaitOnFlagUntilTimeout(hi2c, I2C_FLAG_BTF, RESET, Timeout, tickstart)) {
return -MP_ETIMEDOUT;
}
/* Generate Stop */
if (stop) {
hi2c->Instance->CR1 |= I2C_CR1_STOP;
}
/* Read data from DR */
*dest++ = hi2c->Instance->DR;
len--;
/* Read data from DR */
*dest++ = hi2c->Instance->DR;
len--;
} else {
/* Wait until BTF flag is set */
if (!I2C_WaitOnFlagUntilTimeout(hi2c, I2C_FLAG_BTF, RESET, Timeout, tickstart)) {
return -MP_ETIMEDOUT;
}
/* Disable Acknowledge */
hi2c->Instance->CR1 &= ~I2C_CR1_ACK;
/* Read data from DR */
*dest++ = hi2c->Instance->DR;
len--;
/* Wait until BTF flag is set */
if (!I2C_WaitOnFlagUntilTimeout(hi2c, I2C_FLAG_BTF, RESET, Timeout, tickstart)) {
return -MP_ETIMEDOUT;
}
/* Generate Stop */
if (stop) {
hi2c->Instance->CR1 |= I2C_CR1_STOP;
}
/* Read data from DR */
*dest++ = hi2c->Instance->DR;
len--;
/* Read data from DR */
*dest++ = hi2c->Instance->DR;
len--;
}
} else {
/* Wait until RXNE flag is set */
int ret = I2C_WaitOnRXNEFlagUntilTimeout(hi2c, Timeout, tickstart);
if (ret != 0) {
return ret;
}
/* Read data from DR */
*dest++ = hi2c->Instance->DR;
len--;
if (__HAL_I2C_GET_FLAG(hi2c, I2C_FLAG_BTF) == SET) {
/* Read data from DR */
*dest++ = hi2c->Instance->DR;
len--;
}
}
}
return 0;
}
