STM32F030 UART HalfDuplex config

[Lukasz Przenioslo]

Posted on November 15, 2016 at 23:07

Hello there,

I am trying to configure uart in half duplex mode on STM32F030 device (usage with RS485 later on). I am having difficulties in making the program work properly using the HAL library. This is basically the important part of code: Uart parameters initialization (uart module)

void MX_USART1_UART_Init(void)
{
huart1.Instance = USART1;
huart1.Init.BaudRate = 9600;
huart1.Init.WordLength = UART_WORDLENGTH_9B;
huart1.Init.StopBits = UART_STOPBITS_1;
huart1.Init.Parity = UART_PARITY_EVEN;
huart1.Init.Mode = UART_MODE_TX_RX;
huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;
huart1.Init.OverSampling = UART_OVERSAMPLING_16;
huart1.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;
huart1.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;
if (HAL_RS485Ex_Init(&huart1, UART_DE_POLARITY_HIGH, 16, 16) != HAL_OK)
{
Error_Handler();
}
}

DMA module:

void HAL_UART_MspInit(UART_HandleTypeDef* uartHandle)
{
GPIO_InitTypeDef GPIO_InitStruct;
if(uartHandle->Instance==USART1)
{
/* USER CODE BEGIN USART1_MspInit 0 */
/* USER CODE END USART1_MspInit 0 */
/* Peripheral clock enable */
__HAL_RCC_USART1_CLK_ENABLE();
/**USART1 GPIO Configuration 
PA9 ------> USART1_TX
PA10 ------> USART1_RX
PA12 ------> USART1_DE 
*/
GPIO_InitStruct.Pin = GPIO_PIN_9|GPIO_PIN_10;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_PULLUP;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
GPIO_InitStruct.Alternate = GPIO_AF1_USART1;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
GPIO_InitStruct.Pin = GPIO_PIN_12;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
GPIO_InitStruct.Alternate = GPIO_AF1_USART1;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
/* Peripheral DMA init*/
hdma_usart1_rx.Instance = DMA1_Channel3;
hdma_usart1_rx.Init.Direction = DMA_PERIPH_TO_MEMORY;
hdma_usart1_rx.Init.PeriphInc = DMA_PINC_DISABLE;
hdma_usart1_rx.Init.MemInc = DMA_MINC_ENABLE;
hdma_usart1_rx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;
hdma_usart1_rx.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;
hdma_usart1_rx.Init.Mode = DMA_NORMAL;
hdma_usart1_rx.Init.Priority = DMA_PRIORITY_LOW;
if (HAL_DMA_Init(&hdma_usart1_rx) != HAL_OK)
{
Error_Handler();
}
__HAL_LINKDMA(uartHandle,hdmarx,hdma_usart1_rx);
hdma_usart1_tx.Instance = DMA1_Channel2;
hdma_usart1_tx.Init.Direction = DMA_MEMORY_TO_PERIPH;
hdma_usart1_tx.Init.PeriphInc = DMA_PINC_DISABLE;
hdma_usart1_tx.Init.MemInc = DMA_MINC_ENABLE;
hdma_usart1_tx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;
hdma_usart1_tx.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;
hdma_usart1_tx.Init.Mode = DMA_NORMAL;
hdma_usart1_tx.Init.Priority = DMA_PRIORITY_LOW;
if (HAL_DMA_Init(&hdma_usart1_tx) != HAL_OK)
{
Error_Handler();
}
__HAL_LINKDMA(uartHandle,hdmatx,hdma_usart1_tx);
/* Peripheral interrupt init */
HAL_NVIC_SetPriority(USART1_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(USART1_IRQn);
/* USER CODE BEGIN USART1_MspInit 1 */
/* USER CODE END USART1_MspInit 1 */
}
}

Now I am trying to receive just 1 byte in halfduplex DMA mode here:

retVal += HAL_HalfDuplex_Init(mbs_uartHandle); 
retVal += HAL_HalfDuplex_EnableReceiver(mbs_uartHandle); // should toggle DE?
retVal += HAL_UART_Receive_DMA(mbs_uartHandle, mbs_rawRxDataStream, len);

I place a breakpoint in the ISR routine and wait for interrupt to come after sending one byte, but nothing happens. If I comment out the 1st line (

retVal += HAL_HalfDuplex_Init(mbs_uartHandle); 

) I will get an infite number of interrupt in the ISR, but the code doesnt match any function that the HAL lib checks inside (returns from HAL_UART_IRQHandler(&huart1); without hitting any flag... Infitie times. I was wondering what is wrong with my config? Do I need to perform any additional steps? Also, after I enabled the RS485 functionality (DE line handling), will it automatically work when using send/ receive functions? Or do I need to implement some more myself because the library is not complete? I would appreciate all help regarding this.