Electronic – STM32 UART How to receive 9 bit

stm32

I am trying to understand how I can setup the UART peripheral to receive 9 bit data blocks.

I am using the ST IDE (STM32 cube IDE) and the Nucleo-F103RB board. I can setup the peripheral in 9bit mode using the STM32 Cube. But the HAL function to transmit/receive data still uses an 8bit pointer to a data buffer.

HAL_StatusTypeDef HAL_UART_Receive(UART_HandleTypeDef *huart, uint8_t *pData, uint16_t Size, uint32_t Timeout);

How can I receive the 9th bit?

Best Answer

If you are trying to stuff 9 bits of data into an 8 bit integer, that simply wont work. The compiler would likely cut off the 9th bit, or complain you didn't pass it an array.

You will need to pass it an array of 8 bit integers large enough to capture your received data. In this case, you would need 2 8 bit integers, giving you 16 bits of bit-space for the API to stuff its 9 bits into. The HAL function will write to both integers in the array you passed it. You will need to apply some fancy bit-masking and typecasting to massage the buffer into a native type, or decompose it further into whatever schema you have devised.

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Electrical – STM32 HAL Implementing UART receive Interrupt

With a quick glance I see two potential issues. 1. You need to put the HAL_UART_Receive_ITinside the super loop. 2. The IRQ handler needs to be kept short. What you want to do is put the code in the HAL_UART_RxCpltCallback function which is going to be run after every RX.

It is a good idea to just try to use some the STM32 Cube examples.

Electronic – STM32 HAL_CAN_Transmit always returns TIMEOUT (HAL_CAN_STATE_TIMEOUT)

I got the new version and what a difference there are quite a couple of changes to keep in mind so here are some snippets:


// To send a message
// Old version:
HAL_CAN_Transmit(&hcan1, 10);

//new version:
HAL_CAN_AddTxMessage(&hcan, &TxMessage, TxData, &TxMailbox); 

//To receive a message by polling
        Receive_CAN_Message_Polling(RxMessage, RxData);     

// here is the Polling Function 

void Receive_CAN_Message_Polling(CAN_RxHeaderTypeDef RxMessage_, uint8_t* RxData_){
    uint8_t messages = HAL_CAN_GetRxFifoFillLevel(&hcan, CAN_RX_FIFO0);
        if(messages > 0){
            if(HAL_CAN_GetRxMessage(&hcan, CAN_RX_FIFO0, &RxMessage_, RxData_) == HAL_OK){
            Indicate();             
        }
    }
}

much different to the old Library but it works very well I have not yet looked at the Interrupts and receiving with them but I am sure that they also work fine in the new version of the HAL_CAN Driver

Best Answer

Related Solutions

Electrical – STM32 HAL Implementing UART receive Interrupt

Electronic – STM32 HAL_CAN_Transmit always returns TIMEOUT (HAL_CAN_STATE_TIMEOUT)

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