STM8 serial port receive interrupt cannot enter the problem (STM8L051/101F3)

Preface

I recently got a STM8L051/101F3 development board and planned to play around with it. After I found that the IO and timer were all OK, I started to configure the serial UART and found that the receive interrupt could not be entered, but the send interrupt was OK. Then I started a two-day troubleshooting, and checked almost all possible problem points.

STM8L051/101F3 Development Board

Code

The MCU here is STM8L051F3, and the STM8 library is used for development. The code is as follows for reference only:

main.c

#include "stm8l15x.h"

void Clock_Config(void) 

{

    CLK_SYSCLKDivConfig(CLK_SYSCLKDiv_1); //System clock divider

    CLK_SYSCLKSourceSwitchCmd(ENABLE); //Turn on the system clock switch

    CLK_SYSCLKSourceConfig(CLK_SYSCLKSource_HSI); //Set the system clock source to the internal high-speed clock 16MHz

    while(CLK_GetSYSCLKSource() != CLK_SYSCLKSource_HSI); //Wait for clock switching

}

void GPIO_Config(void)

{

    //USART GPIO

    GPIO_Init(GPIOC, GPIO_Pin_6, GPIO_Mode_In_PU_No_IT);

    GPIO_Init(GPIOC, GPIO_Pin_5, GPIO_Mode_Out_PP_High_Fast);

    SYSCFG_REMAPPinConfig(REMAP_Pin_USART1TxRxPortC, ENABLE);

}

void Usart_Config(void)

{

    CLK_PeripheralClockConfig(CLK_Peripheral_USART1, ENABLE);

    USART_Init(USART1, (uint32)9600, USART_WordLength_8b, USART_StopBits_1, USART_Parity_No, (USART_Mode_TypeDef)(USART_Mode_Tx | USART_Mode_Rx));

    USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);

    USART_ITConfig(USART1, USART_IT_TC, ENABLE);

    USART_Cmd(USART1, ENABLE);

}

void main( void )

{

    Clock_Config();

    GPIO_Config();

    Usart_Config();

    enableInterrupts();

    USART_SendData8(USART1, 0x55);

    while(1)

    {

    }

}

void Usart1_RX_Callback(uint8_t data)

{

    USART_SendData8(USART1, data);

}

stm8l15x_it.c

extern void Usart1_RX_Callback(uint8_t data);

/**

  * @brief USART1 RX / Timer5 Capture/Compare Interrupt routine.

  * @param None

  * @retval None

  */

INTERRUPT_HANDLER(USART1_RX_TIM5_CC_IRQHandler,28)

{

    /* In order to detect unexpected events during development,

       it is recommended to set a breakpoint on the following instruction.

    */

    if(USART_GetITStatus(USART1, USART_IT_RXNE))

    {

// USART_ClearITPendingBit(USART1, USART_IT_RXNE);

        Usart1_RX_Callback(USART_ReceiveData8(USART1));

    }

}

Troubleshooting

First of all, I can be sure that there is no problem with the code. I have checked the registers during simulation with the specification sheet, and all the configurations are correct.

Then I accidentally discovered that the development board can burn programs via the USB serial port, and the burning port used is exactly the serial port IO I use. Then I wondered if there was a conflict between the onboard USB to serial port chip and the external USB to serial port?

Finally I unplugged the onboard RXD jumper, and the serial port receive interrupt came into play...

Remove the RXD jumper

Summarize

If the development board has a USB to serial port, do not insert a USB to serial port module (this is nonsense), otherwise it may affect the serial port transmission and reception, resulting in an inability to receive serial port data.