Use case: USART TX in interrupt mode

Sequence diagram

USART transmit in interrupt mode

@startuml participant "User Application" as p1 participant "HAL USART driver" as p2 participant "USARTX_IRQHandler" as p3 == USART HAL Transmit IT == p1->p2: <color: green> HAL_USART_Transmit_IT(&husart, aTxBuffer, DATA_TO_SEND_SIZE) note over p2 #00FF00 Transmitting data ongoing end note p2-->p1: HAL_OK p3<-: USARTX data interrupt p3->p2: HAL_USART_IRQHandler note over p2 #FFFF99 All data (Size == husart->TxXferCount) have been transmitted end note note over p2 #00FF00 End of transmitting data end note p2->p1: HAL_USART_TxCpltCallback(&husart->TxXferCount) @enduml

Code snippet

HAL1

HAL2 

#define DATA_TO_SEND_SIZE           256

uint8_t aTxBuffer[] = " **** USART_SlaveMode **** ";

USART_HandleTypeDef husart;

/* Ensure that all required peripherals
(USART, GPIO, NVIC,etc.) are configured properly
/*
...
*/

/* USART register Transmit complete user callback */
HAL_USART_RegisterCallback(&husart, HAL_USART_TX_CB_ID,
                               USART_TxCpltCallback);

/* Start a USART Process in interruption mode */
HAL_USART_Transmit_IT(&husart, aTxBuffer,
                              DATA_TO_SEND_SIZE)

#define DATA_TO_SEND_SIZE           256

uint8_t aTxBuffer[] = " **** USART_SlaveMode **** ";

hal_usart_handle_t husart;

/* Ensure that all required peripherals
(USART, GPIO, NVIC,etc.) are configured properly
/*
...
*/

/* USART register Transmit complete user callback */
HAL_USART_RegisterTxCpltCallback(&husart, USART_TxCpltCallback);


/* Start a USART Process in interruption mode */
HAL_USART_Transmit_IT(&husart, aTxBuffer,
                              DATA_TO_SEND_SIZE)

Key changes

  1. HAL2 provides a dedicated registration API for TX completion callbacks: HAL_USART_RegisterTxCpltCallback().

  2. HAL2 uses byte-oriented transfer count fields (for example tx_xfer_count).