STM32L4 - LL_USART_TransmitData8 trigger RXNE

[viniciusfre]

Posted on April 10, 2018 at 14:27

Hello,

I am having a problem with RX interrupt. Everytime I callLL_USART_TransmitData8() it triggers RXNE flag. I enabled only RXNE , ERROR and disabled TXE. Also, If I send bytes to UART does not trigger RXNE interrupt.

I am running the firmware with freeRTOS, so maybe is a priority problem? UART priority is 6 = configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORIT(5) + 1.

void Configure_Modem_USART(void)
{
 /* Enable the peripheral clock of GPIO Port */
 MODEM_USARTx_GPIO_CLK_ENABLE();
 /* Configure Tx Pin as : Alternate function, High Speed, Push pull, Pull up */
 LL_GPIO_SetPinMode(MODEM_USARTx_TX_GPIO_PORT, MODEM_USARTx_TX_PIN, LL_GPIO_MODE_ALTERNATE);
 MODEM_USARTx_SET_TX_GPIO_AF();
 LL_GPIO_SetPinSpeed(MODEM_USARTx_TX_GPIO_PORT, MODEM_USARTx_TX_PIN, LL_GPIO_SPEED_FREQ_HIGH);
 LL_GPIO_SetPinOutputType(MODEM_USARTx_TX_GPIO_PORT, MODEM_USARTx_TX_PIN, LL_GPIO_OUTPUT_PUSHPULL);
 LL_GPIO_SetPinPull(MODEM_USARTx_TX_GPIO_PORT, MODEM_USARTx_TX_PIN, LL_GPIO_PULL_UP);
 /* Configure Rx Pin as : Alternate function, High Speed, Push pull, Pull up */
 LL_GPIO_SetPinMode(MODEM_USARTx_RX_GPIO_PORT, MODEM_USARTx_RX_PIN, LL_GPIO_MODE_ALTERNATE);
 MODEM_USARTx_SET_RX_GPIO_AF();
 LL_GPIO_SetPinSpeed(MODEM_USARTx_RX_GPIO_PORT, MODEM_USARTx_RX_PIN, LL_GPIO_SPEED_FREQ_HIGH);
 LL_GPIO_SetPinOutputType(MODEM_USARTx_RX_GPIO_PORT, MODEM_USARTx_RX_PIN, LL_GPIO_OUTPUT_PUSHPULL);
 LL_GPIO_SetPinPull(MODEM_USARTx_RX_GPIO_PORT, MODEM_USARTx_RX_PIN, LL_GPIO_PULL_UP);
 /* (2) NVIC Configuration for USART interrupts */
 /* - Set priority for USARTx_IRQn */
 /* - Enable USARTx_IRQn */
 NVIC_SetPriority(MODEM_USARTx_IRQn,
 configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY+1);
 NVIC_EnableIRQ(MODEM_USARTx_IRQn);
 /* (2) Enable USART peripheral clock and clock source ***********************/
 MODEM_USARTx_CLK_ENABLE();
 /* Set clock source */
 MODEM_USARTx_CLK_SOURCE();
 /* (3) Configure USART functional parameters ********************************/
 
 // HAL configuration
 USART_ModemHandle.Instance = MODEM_USARTx_INSTANCE;
USART_ModemHandle.Init.BaudRate = 115200;
USART_ModemHandle.Init.WordLength = USART_WORDLENGTH_8B;
USART_ModemHandle.Init.StopBits = USART_STOPBITS_1;
USART_ModemHandle.Init.Parity = USART_PARITY_NONE;
USART_ModemHandle.Init.Mode = UART_MODE_TX_RX;
 //USART_ModemHandle.Init.HwFlowCtl = UART_HWCONTROL_NONE;
USART_ModemHandle.Init.CLKPolarity = USART_POLARITY_HIGH;
USART_ModemHandle.Init.CLKPhase = USART_PHASE_1EDGE;
USART_ModemHandle.Init.CLKLastBit = USART_LASTBIT_ENABLE;
if (HAL_USART_Init(&USART_ModemHandle) != HAL_OK) {}
/* Enable RXNE and Error interrupts, disable TX */
 LL_USART_EnableIT_RXNE(MODEM_USARTx_INSTANCE);
 LL_USART_EnableIT_ERROR(MODEM_USARTx_INSTANCE);
 LL_USART_DisableIT_TXE(MODEM_USARTx_INSTANCE);
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Interrupt handler

void MODEM_USARTx_IRQHandler(void)
{
 __IO uint32_t received_char;
 if (MODEM_USARTx_INSTANCE->ISR & USART_ISR_ORE) // Overrun Error
 MODEM_USARTx_INSTANCE->ICR = USART_ICR_ORECF;
 if (MODEM_USARTx_INSTANCE->ISR & USART_ISR_NE) // Noise Error
 MODEM_USARTx_INSTANCE->ICR = USART_ICR_NCF;
 if (MODEM_USARTx_INSTANCE->ISR & USART_ISR_FE) // Framing Error
 MODEM_USARTx_INSTANCE->ICR = USART_ICR_FECF;
 /* Check RXNE flag value in ISR register */
 if(LL_USART_IsActiveFlag_RXNE(MODEM_USARTx_INSTANCE) &&
 LL_USART_IsEnabledIT_RXNE(MODEM_USARTx_INSTANCE))
 {
 /* RXNE flag will be cleared by reading of RDR register (done in call) */
 if (idx_rx < BUF_SIZE) {
 received_char =
 LL_USART_ReceiveData8(MODEM_USARTx_INSTANCE);
 recv_buff[idx_rx++] = received_char;
 }
 else
 idx_rx = 0;
 }
 else
 {
 /* Call Error function */
 //Error_Callback();
 }
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#freertos #stm32l4-hal #uart-rx-interrupt-routine

[Tesla DeLorean]

Posted on April 10, 2018 at 15:26

If you are talking to a modem you likely have ECHO turned on, use ATE0 to turn that OFF

[viniciusfre · Accepted solution]

Posted on April 10, 2018 at 20:24

Hi,

Problem solved.For some reasonHAL_USART_Init() does not work for transmit and receive with RX interrupt enabled. I am usingLL_USART_Init() instead and works very well.

 LL_USART_InitTypeDef usart_initstruct;
 usart_initstruct.BaudRate = 115200;
 usart_initstruct.DataWidth = LL_USART_DATAWIDTH_8B;
 usart_initstruct.StopBits = LL_USART_STOPBITS_1;
 usart_initstruct.Parity = LL_USART_PARITY_NONE;
 usart_initstruct.TransferDirection = LL_USART_DIRECTION_TX_RX;
 usart_initstruct.HardwareFlowControl = LL_USART_HWCONTROL_NONE;
 usart_initstruct.OverSampling = LL_USART_OVERSAMPLING_16;
 
 /* Initialize USART instance according to parameters defined in initialization structure */
 LL_USART_Init(MODEM_USARTx_INSTANCE, &usart_initstruct);
 /* (5) Enable USART *********************************************************/
 LL_USART_Enable(MODEM_USARTx_INSTANCE);
 
 /* Polling USART initialisation */
 while((!(LL_USART_IsActiveFlag_TEACK(MODEM_USARTx_INSTANCE))) || (!(LL_USART_IsActiveFlag_REACK(MODEM_USARTx_INSTANCE))))
 { 
 }
 /* Enable RXNE and Error interrupts, disable TX */
 LL_USART_EnableIT_RXNE(MODEM_USARTx_INSTANCE);
 LL_USART_EnableIT_ERROR(MODEM_USARTx_INSTANCE);
 LL_USART_DisableIT_TXE(MODEM_USARTx_INSTANCE);�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?