配置引脚复用函数时的一个问题

朱仁宇 · 发表于 2021-11-16 14:29:44

串口1通讯实验，初始化PA9、PA10为复用模式，配置复用函数时用下面的写法能通过编译并且烧录，但是接收不到F4发回来的信息，
GPIO_PinAFConfig(GPIOA,GPIO_PinSource10|GPIO_PinSource9,GPIO_AF_USART1);
如果换成下面的写法就会一切正常：
GPIO_PinAFConfig(GPIOA,GPIO_PinSource10,GPIO_AF_USART1);
GPIO_PinAFConfig(GPIOA,GPIO_PinSource9,GPIO_AF_USART1);
纯新手，想问一下第一种存在什么问题导致失败，谢谢！
全部代码：
#include "stm32f4xx.h"
void USART1_IRQHandler(void);
void My_USART1_Init(void);
int main(void)
{
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
My_USART1_Init();
while(1)
{
};
}

void My_USART1_Init(void)
{
GPIO_InitTypeDef PinStructure;
USART_InitTypeDef USART_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;

RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1,ENABLE);
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA,ENABLE);

PinStructure.GPIO_Mode=GPIO_Mode_AF;
PinStructure.GPIO_OType=GPIO_OType_PP;
PinStructure.GPIO_Pin=GPIO_Pin_9|GPIO_Pin_10;
PinStructure.GPIO_PuPd=GPIO_PuPd_UP;
PinStructure.GPIO_Speed=GPIO_Speed_100MHz;
GPIO_Init(GPIOA,&PinStructure);

GPIO_PinAFConfig(GPIOA,GPIO_PinSource10,GPIO_AF_USART1);
GPIO_PinAFConfig(GPIOA,GPIO_PinSource9,GPIO_AF_USART1);

USART_InitStructure.USART_BaudRate=115200;
USART_InitStructure.USART_HardwareFlowControl=USART_HardwareFlowControl_None;
USART_InitStructure.USART_Mode=USART_Mode_Rx|USART_Mode_Tx;
USART_InitStructure.USART_Parity=USART_Parity_No;
USART_InitStructure.USART_StopBits=USART_StopBits_1;
USART_InitStructure.USART_WordLength=USART_WordLength_8b;
USART_Init(USART1,&USART_InitStructure);
USART_Cmd(USART1,ENABLE);

USART_ITConfig(USART1,USART_IT_RXNE,ENABLE);
NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=1;
NVIC_InitStructure.NVIC_IRQChannelSubPriority =1;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}
void USART1_IRQHandler(void)
{
  u8 r;
  if(USART_GetITStatus(USART1, USART_IT_RXNE) != RESET)
  {
r =USART_ReceiveData(USART1);//(USART1->DR)
USART_SendData(USART1,r);
}
}

远命 · 发表于 2021-11-16 14:29:45

GPIOX_AF寄存器是独立的

void GPIO_PinAFConfig(GPIO_TypeDef* GPIOx, uint16_t GPIO_PinSource, uint8_t GPIO_AF)
{
  uint32_t temp = 0x00;
  uint32_t temp_2 = 0x00;

  /* Check the parameters */
  assert_param(IS_GPIO_ALL_PERIPH(GPIOx));
  assert_param(IS_GPIO_PIN_SOURCE(GPIO_PinSource));
  assert_param(IS_GPIO_AF(GPIO_AF));

  temp = ((uint32_t)(GPIO_AF) << ((uint32_t)((uint32_t)GPIO_PinSource & (uint32_t)0x07) * 4)) ;
  GPIOx->AFR[GPIO_PinSource >> 0x03] &= ~((uint32_t)0xF << ((uint32_t)((uint32_t)GPIO_PinSource & (uint32_t)0x07) * 4)) ;
  temp_2 = GPIOx->AFR[GPIO_PinSource >> 0x03] | temp;
  GPIOx->AFR[GPIO_PinSource >> 0x03] = temp_2;
}