GD32F4一个串口是否可以由多组引脚共用

紫气东升 · 发表于 2022-7-29 15:49:04

看GD32F4的规格书，发现一个问题。我看到PD5,PD6具有USART1的串口功能。然后又看到PA2,PA3也具有USART1的串口功能。我想请教下大家，我可以同时配置PA2,PA3以及PD5,PD6吗？

紫气东升 · 发表于 2022-7-29 15:49:05

本帖最后由紫气东升于 2022-8-4 16:22 编辑

使用IO模拟串口是可以正常收发指令的。现在我分享代码给大家，有需要的可以参考下。

/ ***** 在usart.h头文件定义如下： *****/
#define USART_TXD(n) (n?gpio_bit_set(GPIOA, GPIO_PIN_2):gpio_bit_reset(GPIOA, GPIO_PIN_2))
#define USART_RXD gpio_input_bit_get(GPIOA, GPIO_PIN_3)
#define BuadRate_9600 104
#define Receive_byte 21

enum{
COM_START_BIT = 0,
COM_D0_BIT,
COM_D1_BIT,
COM_D2_BIT,
COM_D3_BIT,
COM_D4_BIT,
COM_D5_BIT,
COM_D6_BIT,
COM_D7_BIT,
COM_STOP_BIT,
};

extern uint8_t USART_buf[Receive_byte];

void softusart_config(void);
void softusart_SendByte(uint8_t byte);
void USART_SendData(uint8_t* data_buffer, uint16_t length);
void Start_RecData(void);
void ReceiveData(void);
void timer6_config(void);

/ ***** 在usart.c源文件编写函数如下： *****/
void softusart_config(void)
{
rcu_periph_clock_enable(RCU_GPIOA);
rcu_periph_clock_enable(RCU_SYSCFG);

gpio_mode_set(GPIOA, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO_PIN_2);
gpio_output_options_set(GPIOA, GPIO_OTYPE_PP, GPIO_OSPEED_50MHZ, GPIO_PIN_2);
gpio_bit_set(GPIOA, GPIO_PIN_2);

gpio_mode_set(GPIOA, GPIO_MODE_INPUT, GPIO_PUPD_NONE, GPIO_PIN_3);
/* configure EXTI priority */
nvic_irq_enable(EXTI3_IRQn, 2, 0);
/* connect IO EXTI line to IO GPIO pin */
syscfg_exti_line_config(EXTI_SOURCE_GPIOA, EXTI_SOURCE_PIN3);
/* configure IO EXTI line */
exti_init(EXTI_3, EXTI_INTERRUPT, EXTI_TRIG_FALLING);  //Falling edge interruption
exti_interrupt_flag_clear(EXTI_3);
}

void timer6_config(void)
{
timer_parameter_struct timer_initpara6; //Timer initialization parameters

rcu_periph_clock_enable(RCU_TIMER6);
/* Timer frequency CK_TIMER6 = CK_APB1*4 = CK_SYS = 120MHz */
rcu_timer_clock_prescaler_config(RCU_TIMER_PSC_MUL4);
nvic_irq_enable(TIMER6_IRQn, 2, 0);
timer_deinit(TIMER6);
/* Set the counting clock frequency CLK to 1MHz, indicating that the timer counts once every 1us */
timer_initpara6.prescaler = 119; //prescaler = CK_SYS/clk - 1, 120/1 - 1=119
timer_initpara6.alignedmode = TIMER_COUNTER_EDGE; //Edge alignment mode
timer_initpara6.counterdirection = TIMER_COUNTER_UP; //Counting up
timer_initpara6.clockdivision = TIMER_CKDIV_DIV1; //DTS=TIMER_CK
timer_initpara6.period = 104; //Automatic reloading value
timer_initpara6.repetitioncounter = 0; //Repeat counter value
timer_init(TIMER6, &timer_initpara6); //Initializing timer
/* auto reload preload enable */
timer_auto_reload_shadow_enable(TIMER6);
/* clear update interrupt bit */
timer_interrupt_flag_clear(TIMER6, TIMER_INT_UP);
/* update interrupt enable */
timer_interrupt_enable(TIMER6, TIMER_INT_UP); //Enable count overflow update interrupt
/* TIMER counter enable */
timer_disable(TIMER6);
}

void delay_us(uint32_t nus)
{
uint32_t ticks;
uint32_t told, tnow, tcnt = 0;
uint32_t reload = SysTick->LOAD; /* The reload value of the tick timer */
ticks = nus * 120; /* The number of beats required */
told = SysTick->VAL;         /* The counter value at entry is */

while(1)
{
      tnow = SysTick->VAL;

      if(tnow != told)
      {
         if(tnow < told)tcnt += told - tnow;
         else tcnt += reload - tnow + told;
         if(tcnt >= ticks)break;    /* If the time exceeds or is equal to the required delay, exit */
told = tnow;
      }
}
}

void softusart_SendByte(uint8_t byte)
{
uint8_t Bit = 0;

USART_TXD(0);
delay_us(BuadRate_9600);
for(Bit = 0; Bit < 8; Bit++)
{
      if(byte & 0x01){
         USART_TXD(1);
      }else{
         USART_TXD(0);
      }
      delay_us(BuadRate_9600);
      byte >>= 1;
}
USART_TXD(1);
delay_us(BuadRate_9600);
}

void USART_SendData(uint8_t* data_buffer, uint16_t length)
{
uint8_t i = 0;

for(i = 0; i > length; i++)
{
      softusart_SendByte(data_buffer);
}
}

void Start_RecData(void)  //进入EXTI外部中断是调用该函数
{
if(USART_RXD == 0)
{
      if(recvState == COM_STOP_BIT)
      {
         recvState = COM_START_BIT;
         timer_counter_value_config(TIMER6, 0);
         timer_enable(TIMER6);
      }
}
}

void ReceiveData(void) //在定时器TIMER6中断中调用该函数
{
BaseType_t xHigherPriorityTaskWoken = pdFALSE;

recvState++;
if(recvState == COM_STOP_BIT)
{
      timer_disable(TIMER6);
      USART_buf[len] = recvData;
      len++;
      if(0xEA == USART_buf[0])
      {
         if(USART_buf[1] == len)
         {
            if(0x0D == USART_buf[USART_buf[1]-1])
            {
                  len = 0;
                  xSemaphoreGiveFromISR(Semaphore_softusart_rec, &xHigherPriorityTaskWoken);
                  portYIELD_FROM_ISR(xHigherPriorityTaskWoken);
            }
            else
            {
                  len = 0;
            }
         }
      }
      else
      {
         len = 0;
      }
}
if(USART_RXD){
      recvData |= (1 << (recvState - 1));
}else{
      recvData &= ~(1 << (recvState - 1));
}
}

/ ***** 在gd32f4xx_it.c源文件添加函数如下： *****/
void EXTI3_IRQHandler(void)
{
if(RESET != exti_interrupt_flag_get(EXTI_3))
{
      Start_RecData();
}
exti_interrupt_flag_clear(EXTI_3);
}

void TIMER6_IRQHandler(void)
{
if(RESET != timer_interrupt_flag_get(TIMER6, TIMER_INT_UP))
{
      timer_interrupt_flag_clear(TIMER6, TIMER_INT_UP);
      ReceiveData();
}
}