Kendryte K210 use of uart on freertos

First modify the project_cfg.h file to define the hardware-defined i2c pins, where 40 and 41 represent IO40 and IO41, as follows:

const fpioa_cfg_t g_fpioa_cfg =
{
    .version = PIN_CFG_VERSION,
    .functions_count = 2,
    .functions =
    {
        {40, FUNC_UART1_RX},
        {41, FUNC_UART1_TX}
    }
};

Then in the main function is as follows:

//打开uart1
uart1 = io_open("/dev/uart1");

//设置uart1
uart_config(uart1, 9600, 8, UART_STOP_1, UART_PARITY_NONE);

char hel[8] = {0x11,0x22,0x33,0x44,0x55,0x66,0x0d,0x0a};
   
while (1)
{
    //循环发送，每次发送8个字节数据
    io_write(uart1, (uint8_t *)hel, 8);
}

It is worth noting that this is only a routine for sending, but there is a problem with receiving. The receiving is blocked. If there are multiple threads, there will be problems. Although there is a timeout setting, it does not have much effect and is currently in the process of testing. It is found that the received buf is only 64 bytes.