ST STM32F2 User Manual

UM1940
Overview of HAL drivers
DocID028236 Rev 2
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HAL_USART_TxCpltCallback() and HAL_USART_ErrorCallback() should be linked in the
HAL_PPP_Process_DMA() function to the DMA transfer complete callback and the DMA
transfer Error callback by using the following statement:
HAL_PPP_Process_DMA (PPP_HandleTypeDef *hppp, Params….)
{
(…)
hppp->DMA_Handle->XferCpltCallback = HAL_UART_TxCpltCallback ;
hppp->DMA_Handle->XferErrorCallback = HAL_UART_ErrorCallback ;
(…)
}
2.12.4 Timeout and error management
2.12.4.1 Timeout management
The timeout is often used for the APIs that operate in Polling mode. It defines the delay
during which a blocking process should wait till an error is returned. An example is provided
below:
HAL_StatusTypeDef HAL_DMA_PollForTransfer(DMA_HandleTypeDef *hdma, uint32_t
CompleteLevel, uint32_t Timeout)
The timeout possible value are the following:
Table 15: Timeout values
Timeout value
Description
0
No poll : Immediate process check and exit
1 ... (HAL_MAX_DELAY -1)
(1)
Timeout in ms
HAL_MAX_DELAY
Infinite poll till process is successful
Notes:
(1)
HAL_MAX_DELAY is defined in the stm32f2xx_hal_def.h as 0xFFFFFFFF
However, in some cases, a fixed timeout is used for system peripherals or internal HAL
driver processes. In these cases, the timeout has the same meaning and is used in the
same way, except when it is defined locally in the drivers and cannot be modified or
introduced as an argument in the user application.
Example of fixed timeout:
#define LOCAL_PROCESS_TIMEOUT 100
HAL_StatusTypeDef HAL_PPP_Process(PPP_HandleTypeDef)
{
(…)
timeout = HAL_GetTick() + LOCAL_PROCESS_TIMEOUT;
(…)
while(ProcessOngoing)
{
(…)
if(HAL_GetTick() >= timeout)
{
/* Process unlocked */
__HAL_UNLOCK(hppp);
hppp->State= HAL_PPP_STATE_TIMEOUT;
return HAL_PPP_STATE_TIMEOUT;
}
}
(…)
}

ST STM32F2 Specifications

General

Brand	ST
Model	STM32F2
Category	Microcontrollers
Language	English