STM8L USART serial port debugging

I have recently been learning to develop STM8 MCU. I have just got this MCU and don’t know many of its functions well. I can only learn while developing. I will record the learning process. If there are any mistakes, please correct me.

MCU: STM8L151K4 

Environment: IAR FOR STM8

Due to project requirements, the USART function needs to be debugged. At the beginning, there was no schematic diagram, only the board and datasheet. From the datesheet, I saw that the USART RX TX pins were PC2 PC3. 

So I directly configured PC2 PC3 and then initialized it. However, when the code was running, I did not receive the data sent by the MCU. I checked the code and datasheet, and then searched for information online. I found that USART has a remappin function, which maps PC3 PC2 to PA2 PA3. 

So I asked the hardware and confirmed that the USART hardware pins on the board were PA2 PA3, so I reconfigured the relevant code, remapped the pins, and tested it.

Although it wasted some time, I still gained something.

Some of the code is as follows:

#define USART_TX_PORT GPIOA

#define USART_RX_PORT GPIOA

#define USART_TX_PINS GPIO_Pin_2

#define USART_RX_PINS GPIO_Pin_3

void uart_gpio_init()

{

    GPIO_Init(USART_TX_PORT,USART_TX_PINS, GPIO_Mode_Out_PP_Low_Fast);

    GPIO_Init(USART_RX_PORT,USART_RX_PINS, GPIO_Mode_In_PU_No_IT);

}

void uart_init(void)

{

    uart_gpio_init();   

    CLK_PeripheralClockConfig(CLK_Peripheral_USART1, ENABLE);

    //remapping

    SYSCFG_REMAPPinConfig(REMAP_Pin_USART1TxRxPortA,ENABLE);

    USART_DeInit(USART1);

    /* UART1 configuration ------------------------------------------------------*/

    /* UART1 configured as follow:

        - USARTx = 1

        - BaudRate = 9600baud  

        - USART_WordLength = 8 Bits

        -One Stop Bit

        - No parity

        - Receive and transmit enabled

    */

    USART_Init(USART1, (uint32_t)9600, USART_WordLength_8b, USART_StopBits_1, USART_Parity_No, (USART_Mode_TypeDef)(USART_Mode_Tx | USART_Mode_Rx));

    USART_Cmd(USART1, ENABLE);

}

If the USART hardware is directly connected to PC2 PC3, there is no need for SYSCFG_REMAPPinConfig to remap.