STM32F4 UART DMA

[KondenserSoketi]

Hello all,

I have a project using UART DMA for receive datas from Nextion HMI. When i touch a button on Nextion Screen, data should be received a buffer via UART DMA. 

First five hour it works good but after five hours no data flows. It is like the button doesnt work. I checked wire and other hardware stuff. They are all OK. It seems my code is wrong. Can anyone help to find where is the mistake? Shold i arrange flags?

Thanks in advance. You can find the code below.

void HAL_UARTEx_RxEventCallback(UART_HandleTypeDef *huart, uint16_t Size)

{

if(huart->Instance == USART3)

{

HAL_UARTEx_ReceiveToIdle_DMA(&huart3, rx_data_ekran, sizeof(rx_data_ekran));

__HAL_DMA_DISABLE_IT(&hdma_usart3_rx, DMA_IT_HT);

  if(rx_data_ekran[2] == 2){ // ON-OFF  button control

    if((rx_data_ekran[3] == 0)) // ON-OFF IKB OFF

    {

    bIKB_On_manuel = false;

  //NEXTION_SendNum("n1", 0);

    }

    else if((rx_data_ekran[3] == 1)) //  IKB ON

    {

    bIKB_On_manuel = true;

  //NEXTION_SendNum("n1", 1);

    }

    }

//

//

    if(rx_data_ekran[2] == 3 && rx_data_ekran[3] == 1){ // Oto Mod Kontrol

    bOtoModAktif_manuel = true;

    bManuelModAktif_manuel = false;

    bMod2= false;

           }

    else if(rx_data_ekran[2] == 47 && rx_data_ekran[3] == 1){ // Mod2 Kontrol

    bMod2 = true;

    bOtoModAktif_manuel = false;

    bOtoModAktif_manuel = false;

    }

}

}

[Tesla DeLorean]

You're going to want to test and clear receiver errors, like Noise, Framing, Overrun, etc.

If not errors/issues in UART, check DMA unit reporting.

[Piranha]

UART is a stream interface, not message interface... One cannot just look for the data at a constant offset in the buffer - one has to find the beginning of the message according to the used higher layer protocol and parse that message properly.

The HAL_UARTEx_RxEventCallback() function is also called on the IDLE event and doen't mean that all of the buffer is full. That's why it has a Size parameter. And, on top of that, the HAL_UARTEx_ReceiveToIdle_DMA() call is not guaranteed to succeed...

https://community.st.com/t5/stm32-mcus-products/stm32f401-hal-uart-dma-qna/td-p/569223

Learn this:

https://github.com/MaJerle/stm32-usart-uart-dma-rx-tx