AnsweredAssumed Answered

STM32F103 USART RX interrupt notfires, then stuck

Question asked by csabafrom thehill on Aug 28, 2017
Latest reply on Aug 31, 2017 by csabafrom thehill

Hi,

 

I try to receive characters over USART1 using the StdPeriphLibrary (System Workbench STM32, MCU is SM32F103C8B), but after I get the data the program stuck (transmission works perfectly).

The ISR is:

 

void USART1_IRQHandler(void)
{
    uint16_t rx;
    if(USART_GetITStatus(USART1,USART_IT_RXNE)!=RESET) // check RX interrupt
        {
        rx = USART_ReceiveData(USART1);        
        led_toggle();        
        }
}

Whenever data arrives the LED should toggle, but nothing happens, just hangs the code.

 

USART settings:

 

void USART1_Init(void)
{
    /* USART configuration structure for USART1 */
    USART_InitTypeDef usart1_init_struct;
    /* Bit configuration structure for GPIOA PIN9 and PIN10 */
    GPIO_InitTypeDef gpioa_init_struct;
     
    /* Enalbe clock for USART1, AFIO and GPIOA */
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1 | RCC_APB2Periph_AFIO |
                           RCC_APB2Periph_GPIOA, ENABLE);
                            
    /* GPIOA PIN9 alternative function Tx */
    gpioa_init_struct.GPIO_Pin = GPIO_Pin_9;
    gpioa_init_struct.GPIO_Speed = GPIO_Speed_50MHz;
    gpioa_init_struct.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_Init(GPIOA, &gpioa_init_struct);
    /* GPIOA PIN9 alternative function Rx */
    gpioa_init_struct.GPIO_Pin = GPIO_Pin_10;
    gpioa_init_struct.GPIO_Speed = GPIO_Speed_50MHz;
    gpioa_init_struct.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init(GPIOA, &gpioa_init_struct);
 
    /* Enable USART1 */
    USART_Cmd(USART1, ENABLE); 
    /* Baud rate 9600, 8-bit data, One stop bit
     * No parity, Do both Rx and Tx, No HW flow control
     */
    usart1_init_struct.USART_BaudRate = 9600;  
    usart1_init_struct.USART_WordLength = USART_WordLength_8b; 
    usart1_init_struct.USART_StopBits = USART_StopBits_1;  
    usart1_init_struct.USART_Parity = USART_Parity_No ;
    usart1_init_struct.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
    usart1_init_struct.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
    /* Configure USART1 */
    USART_Init(USART1, &usart1_init_struct);
    /* Enable RXNE interrupt */
    USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);
    /* Enable USART1 global interrupt */
    NVIC_EnableIRQ(USART1_IRQn);
}

(the original code is from here )

 

Polling the RX works well.

 

Is there any suggestions?

Outcomes