stm32-uart-issue.c

UART_HandleTypeDef Device_UART_Handle;

int main(void) {
    HAL_Init();
    RCC_Init();
    Debug_UART_Init();

    printf("\n\n\nBooting uart-test / %d\r\n", RANDOM);

    printf("Enabling device UART\r\n");

    // Start clocks
    __GPIOA_CLK_ENABLE();
    __AFIO_CLK_ENABLE();
    __USART2_CLK_ENABLE();

    // Enable GPIOs for alternate function
    GPIO_InitTypeDef GPIO_Config = {
      .Pull  = GPIO_NOPULL,
      .Speed = GPIO_SPEED_HIGH,
    };

    GPIO_Config.Pin   = GPIO_PIN_2;
    GPIO_Config.Mode  = GPIO_MODE_AF_PP;
    HAL_GPIO_Init(GPIOA, &GPIO_Config);

    GPIO_Config.Pin   = GPIO_PIN_3;
    GPIO_Config.Mode  = GPIO_MODE_INPUT;
    HAL_GPIO_Init(GPIOA, &GPIO_Config);

    UART_InitTypeDef UART_Config = {
      .BaudRate     = 115200,
      .Mode         = UART_MODE_TX_RX,
      .WordLength   = UART_WORDLENGTH_8B,
      .HwFlowCtl    = UART_HWCONTROL_NONE,
      .StopBits     = UART_STOPBITS_1,
      .Parity       = UART_PARITY_NONE,
    };

    Device_UART_Handle.Instance = USART2;
    Device_UART_Handle.Init = UART_Config;

    HAL_UART_Init(&Device_UART_Handle);

    char *cmd = "AT\r\n";
    uint32_t len = strlen(cmd);

    printf("Sending %d bytes: %s\n\r  Echo:\r\n", (unsigned int)len, cmd);

    // Send 1 byte at a time, receiving the echo
    for(uint32_t i = 0; i < len; i++) {
        uint8_t echoChar;

        if (HAL_UART_Transmit(&Device_UART_Handle, (uint8_t *)cmd + i, 1, 5000) != HAL_OK) {
            printf("    Send fail\r\n");
            while(1) {}
        }

        if (HAL_UART_Receive(&Device_UART_Handle, &echoChar, 1, 5000) != HAL_OK) {
            printf("    Echo recv fail\r\n");
            while(1) {}
        }

        printf("    Byte %d: sent %d, echo %d (ORE %d)\r\n", (unsigned int)i, *(cmd + i), echoChar, __HAL_UART_GET_FLAG(&Device_UART_Handle, UART_FLAG_ORE));
    }

    printf("  Receive:\n\r");

    // Attempt to read the remaining data
    // 7 chars left: \n \r \n O  K  \r \n
    //         ints: 10 13 10 79 75 13 10
    while (1) {
        uint8_t recvChar;
        if (HAL_UART_Receive(&Device_UART_Handle, &recvChar, 1, 5000) != HAL_OK) {
            printf("    Recv fail\r\n");
            printf("    RXNE: %d ORE: %d NE: %d FE: %d PE: %d\r\n",
                __HAL_UART_GET_FLAG(&Device_UART_Handle, UART_FLAG_RXNE),
                __HAL_UART_GET_FLAG(&Device_UART_Handle, UART_FLAG_ORE),
                __HAL_UART_GET_FLAG(&Device_UART_Handle, UART_FLAG_NE),
                __HAL_UART_GET_FLAG(&Device_UART_Handle, UART_FLAG_FE),
                __HAL_UART_GET_FLAG(&Device_UART_Handle, UART_FLAG_PE));
            while(1) {}
        }
        printf("    Recv %d\r\n", recvChar);
    }
}