对WaitOnFlagUntilTimeout（）这个函数名不理解
看输出名，以为这个函数是比较参数2和参数3是否一致。结果仔细看代码，好像是参数2和参数3不一致的话，才返回hal_ok，否则返回hal_timeout.
/**
* @briefThis function handles SPI Communication Timeout.
* @paramhspi: pointer to a SPI_HandleTypeDef structure that contains
* the configuration information for SPI module.
* @paramFlag: SPI flag to check
* @paramStatus: Flag status to check: RESET or set
* @paramTimeout: Timeout duration
* @retval HAL status
*/
static HAL_StatusTypeDef SPI_WaitOnFlagUntilTimeout(SPI_HandleTypeDef *hspi,
uint32_t Flag, FlagStatus Status, uint32_t Timeout)
{
uint32_t tickstart = 0;
/* Get tick */
tickstart = HAL_GetTick();
/* Wait until flag is set */
if (Status == RESET)
{
while (__HAL_SPI_GET_FLAG(hspi, Flag) == RESET)
{
if (Timeout != HAL_MAX_DELAY)
{
if ((Timeout == 0) || ((HAL_GetTick() - tickstart) > Timeout))
{
/* Disable the SPI and reset the CRC: the CRC value should be cleared
on both master and slave sides in order to resynchronize the master
and slave for their respective CRC calculation */
/* Disable TXE, RXNE and ERR interrupts for the interrupt process */
__HAL_SPI_DISABLE_IT(hspi,
(SPI_IT_TXE | SPI_IT_RXNE | SPI_IT_ERR));
/* Disable SPI peripheral */
__HAL_SPI_DISABLE(hspi);
/* Reset CRC Calculation */
if (hspi->Init.CRCCalculation == SPI_CRCCALCULATION_ENABLE)
{
SPI_RESET_CRC(hspi);
}
hspi->State = HAL_SPI_STATE_READY;
/* Process Unlocked */
__HAL_UNLOCK(hspi);
return HAL_TIMEOUT;
}
}
}
}
else
{
while (__HAL_SPI_GET_FLAG(hspi, Flag) != RESET)
{
if (Timeout != HAL_MAX_DELAY)
{
if ((Timeout == 0) || ((HAL_GetTick() - tickstart) > Timeout))
{
/* Disable the SPI and reset the CRC: the CRC value should be cleared
on both master and slave sides in order to resynchronize the master
and slave for their respective CRC calculation */
/* Disable TXE, RXNE and ERR interrupts for the interrupt process */
__HAL_SPI_DISABLE_IT(hspi,
(SPI_IT_TXE | SPI_IT_RXNE | SPI_IT_ERR));
/* Disable SPI peripheral */
__HAL_SPI_DISABLE(hspi);
/* Reset CRC Calculation */
if (hspi->Init.CRCCalculation == SPI_CRCCALCULATION_ENABLE)
{
SPI_RESET_CRC(hspi);
}
hspi->State = HAL_SPI_STATE_READY;
/* Process Unlocked */
__HAL_UNLOCK(hspi);
return HAL_TIMEOUT;
}
}
}
}
return HAL_OK;
}
就是一个等待超时的判断 如果等待的状态在指定的时间内到了就ok
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