stm32串口，同时初始化后，3正常，2不管用

只看该作者 · 2012-11-26 18:31

void SER2_Init (void) {
  RCC->APB1ENR  |= (1UL << 17);       /* Enable USART2 clock             */
  RCC->AHB1ENR  |= (1UL << 3);       /* Enable GPIOD clock                */
  /* Connect PD5 and PD6 to Alternate Function 7 (AF7) */
  GPIOD->MODER  &= (3 << 2*5) | (3 << 2*6);
  GPIOD->MODER  |= (2 << 2*5) | (2 << 2*6);
  GPIOD->AFR[0] &= ~0x0FF00000;
  GPIOD->AFR[0] |=  0x07700000;
  /* Configure USART2: 115200 baud @ 42MHz, 8 bits, 1 stop bit, no parity    */
  USART2->BRR = (22 << 4) | 12;
  USART2->CR3 = 0x0000;
  USART2->CR2 = 0x0000;
  USART2->CR1 = 0x200C;
}
void SER3_Init (void) {
  int i;
  GPIO_InitTypeDef GPIO_InitStructure;

  RCC->APB1ENR  |=  ( 1 << 18);    /* Enable USART3 clock */
  RCC->AHB1ENR  |=  ( 1 <<  3);    /* Enable GPIOD clock  */

/* Connect PD8 and PD9 to Alternate Function 7 (AF7) */
  GPIOD->MODER  &= (3 << 2*8) | (3 << 2*9);
  GPIOD->MODER  |= (2 << 2*8) | (2 << 2*9);
  GPIOD->AFR[1] &= ~0x000000FF;
  GPIOD->AFR[1] |=  0x00000077;
  /* Configure USART2: 115200 baud @ 42MHz, 8 bits, 1 stop bit, no parity    */
  USART3->BRR = (22 << 4) | 12;
  USART3->CR3 = 0x0000;
  USART3->CR2 = 0x0000;
  for (i = 0; i < 0x1000; i++) __NOP(); /* avoid unwanted output             */
  USART3->CR1 = 0x200C;
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);
GPIO_InitStructure.GPIO_Mode =  GPIO_Mode_OUT;
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11;
GPIO_Init(GPIOD, &GPIO_InitStructure);
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);
GPIO_InitStructure.GPIO_Mode =  GPIO_Mode_OUT;
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3;
GPIO_Init(GPIOD, &GPIO_InitStructure);
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);
GPIO_InitStructure.GPIO_Mode =  GPIO_Mode_OUT;
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;
GPIO_Init(GPIOD, &GPIO_InitStructure);
}

1万 · 2012-11-27 20:24

我怀疑 IO 口配置的问题

只看该作者 · 2012-12-2 22:44

感觉stm的库很容易上手，但是也很容易云里雾里的把人绕进去

只看该作者 · 2012-12-3 13:42

Peripherial Clock ....

RCC_APB1PeriphClockCmd<--UART3
RCC_APB2PeriphClockCmd<--UART2

please modify your code as below ,
RCC->APB2ENR |= (1UL << 17); /* Enable USART2 clock */
RCC->AHB2ENR |= (1UL << 3); /* Enable GPIOD clock */