关于STM32F407ZGT6的一些知识小结及串口1程序（转载）

1万 · 2018-12-14 10:28

一、关于STM32F4在通过串口通信的时候乱码问题
1.刚开始弄得时候，以为和stm32一样配置完串口之后就可以用了，结果后面发现串口打印出来的东西全是乱码。后面发现是STM32F4的固件库中使用的频率是25Mhz，而板子上的外部晶振是8Mhz的。因此需要去固件库的stm32f4xx.h中把HSE_VALUE改成8Mhz就可以了。

1万 · 2018-12-14 10:28

2.还有一种问题是，如果使用的是电平转换的问题。要直接从芯片的引脚进行通信的话，可以直接用一个TTL下载器直接相连，如CH340；如果板子上带有MAX3232芯片的电平转换，要通过DB9插口线转RS232电平为TTL电平然后和电脑相连。

#include "stm32f4xx.h"
#include "stdio.h"
#include "uart.h"
void nvic_config(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
/* NVIC configuration */
/* Configure the Priority Group to 2 bits */
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);

/* Enable the USARTx Interrupt */
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);
}
/**
  * @brief Main program
  * @param  None
  * @retval None
  */
int main(void)
{
nvic_config();
uart_init();

while(1)
{
      printf("hello!welcome to F4..1H.\r\n ");
}
}

#ifdef  USE_FULL_ASSERT

/**
  * @brief  Reports the name of the source file and the source line number
  *       where the assert_param error has occurred.
  * @param  file: pointer to the source file name
  * @param  line: assert_param error line source number
  * @retval None
  */
void assert_failed(uint8_t* file, uint32_t line)
{
  /* User can add his own implementation to report the file name and line number,
   ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */

  /* Infinite loop */
  while (1)
  {
  }
}
#endif

/**
  * @}
  */

/**
  * @}
  */

1万 · 2018-12-14 10:29

#include "uart.h"
#include "stdio.h"

void uart_init(void)
{
USART_InitTypeDef USART_InitStructure;
GPIO_InitTypeDef GPIO_InitStructure;

/* 开启GPIO_B的时钟 */
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);
/* 开启串口1的时钟 */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);

GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_UP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;
GPIO_Init(GPIOB, &GPIO_InitStructure);

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7;
GPIO_Init(GPIOB, &GPIO_InitStructure);

GPIO_PinAFConfig(GPIOB, GPIO_PinSource6, GPIO_AF_USART1);
GPIO_PinAFConfig(GPIOB, GPIO_PinSource7, GPIO_AF_USART1);

USART_InitStructure.USART_BaudRate = 115200;
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_Tx | USART_Mode_Rx;

USART_Init(USART1, &USART_InitStructure);

/* 使能串口1 */
USART_Cmd(USART1, ENABLE);
USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);
}

int fputc(int ch, FILE *f)
{
/* Place your implementation of fputc here */
/* e.g. write a character to the USART */
USART_SendData(USART1, (uint8_t) ch);

/* Loop until the end of transmission */
while (USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET)
{}

return ch;
}