初始化GD32W51芯片的串口1，重映射到PC1和PC0以及初始化这两个GPIO引脚，发送字符0xFF

我可以回答这个问题。初始化GD32W51芯片的串口1，重映射到PC1和PC0以及初始化这两个GPIO引脚，可以使用以下代码：

#include "gd32f4xx.h"

void init_uart1(void)
{
    /* enable the peripherals clock */
    rcu_periph_clock_enable(RCU_USART1);
    rcu_periph_clock_enable(RCU_GPIOC);

    /* configure USART1 Tx as alternate function push-pull */
    gpio_init(GPIOC, GPIO_MODE_AF_PP, GPIO_OSPEED_50MHZ, GPIO_PIN_0);
    /* configure USART1 Rx as alternate function push-pull */
    gpio_init(GPIOC, GPIO_MODE_AF_PP, GPIO_OSPEED_50MHZ, GPIO_PIN_1);

    /* USART1 configuration */
    usart_deinit(USART1);
    usart_baudrate_set(USART1, 115200U);
    usart_word_length_set(USART1, USART_WL_8BIT);
    usart_stop_bit_set(USART1, USART_STB_1BIT);
    usart_parity_config(USART1, USART_PM_NONE);
    usart_hardware_flow_rts_config(USART1, USART_RTS_DISABLE);
    usart_hardware_flow_cts_config(USART1, USART_CTS_DISABLE);
    usart_receive_config(USART1, USART_RECEIVE_ENABLE);
    usart_transmit_config(USART1, USART_TRANSMIT_ENABLE);

    usart_enable(USART1);
}

void init_gpio(void)
{
    /* enable the peripherals clock */
    rcu_periph_clock_enable(RCU_GPIOC);

    /* configure PC0 and PC1 as output */
    gpio_init(GPIOC, GPIO_MODE_OUT_PP, GPIO_OSPEED_50MHZ, GPIO_PIN_0);
    gpio_init(GPIOC, GPIO_MODE_OUT_PP, GPIO_OSPEED_50MHZ, GPIO_PIN_1);
}

int main(void)
{
    init_uart1();
    init_gpio();

    /* send 0xFF */
    usart_data_transmit(USART1, 0xFF);

    while (1);

    return 0;
}