stm32f405v基础例程

以下是基础例程的步骤：

1. 设置时钟：使用RCC库函数设置系统时钟。

2. 初始化GPIO：使用GPIO库函数初始化需要使用的GPIO引脚。

3. 配置USART：使用USART库函数配置串口通信参数和中断。

4. 发送数据：使用USART库函数发送数据。

下面是一个简单的基础例程：

#include "stm32f4xx.h"
#include "stm32f4xx_gpio.h"
#include "stm32f4xx_usart.h"
#include "misc.h"

void Delay(__IO uint32_t nCount) {
  while(nCount--) {
  }
}

int main(void) {
  GPIO_InitTypeDef GPIO_InitStructure;
  USART_InitTypeDef USART_InitStructure;
  NVIC_InitTypeDef NVIC_InitStructure;

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

  /* Configure USART1 Tx (PA.09) as alternate function push-pull */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

  /* Configure USART1 Rx (PA.10) as input floating */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

  /* USART1 configuration */
  USART_InitStructure.USART_BaudRate = 9600;
  USART_InitStructure.USART_WordLength = USART_WordLength_8b;
  USART_InitStructure.USART_StopBits = USART_StopBits_1;
  USART_InitStructure.USART_Parity = USART_Parity_No;
  USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
  USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
  USART_Init(USART1, &USART_InitStructure);

  /* NVIC configuration */
  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);

  NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);

  /* Enable USART1 */
  USART_Cmd(USART1, ENABLE);

  while (1) {
    USART_SendData(USART1, 'A');
    while (USART_GetFlagStatus(USART1, USART_FLAG_TC) == RESET);
    Delay(0xFFFFF);
  }
}

void USART1_IRQHandler(void) {
  if (USART_GetITStatus(USART1, USART_IT_RXNE) != RESET) {
    /* Clear the USART1 RX interrupt */
    USART_ClearITPendingBit(USART1, USART_IT_RXNE);

    /* Do something when a byte is received */
  }
}

这个例程使用了USART1和PA9和PA10引脚进行通信。在主函数中，首先配置了PA9引脚为输出和PA10引脚为输入，并且配置了USART1的参数。然后，发送了一个字符'A'，并等待发送完成。在中断服务函数中，当接收到一个字节时，会执行一些代码。