无论是在51单片机还是在stm32,默认printf串口都是串口一。使用printf的时候头文件为"stdio.h",但是一些外部设备与单片机连接的时候使用的是串口(通常物联网用到的ESP8266,SIM9600等都是通过串口发送AT指令进行模式的配置的),但是printf函数却只有一个。在单片机中printf函数默认为串口一。所以试想能不能其他串口也组成类似于printf的函数。
printf()
引入头文件
#include <stdio.h>
关键部分代码
#ifdef __GNUC__
/* With GCC, small printf (option LD Linker->Libraries->Small printf
set to 'Yes') calls __io_putchar() */
#define PUTCHAR_PROTOTYPE int __io_putchar(int ch)
#else
#define PUTCHAR_PROTOTYPE int fputc(int ch, FILE *f)
#endif /* __GNUC__ */
/* USER CODE BEGIN 1 */
PUTCHAR_PROTOTYPE
{
/* Place your implementation of fputc here */
/* e.g. write a character to the USART2 and Loop until the end of transmission */
HAL_UART_Transmit(&huart1, (uint8_t *)&ch, 1, 0xFFFF);
return ch;
}
u3_printf()
引入头文件
#include <stdarg.h>
其文件内容部分为
#ifdef __clang__
typedef __builtin_va_list va_list;
#define va_start(ap, param) __builtin_va_start(ap, param)
#define va_end(ap) __builtin_va_end(ap)
#define va_arg(ap, type) __builtin_va_arg(ap, type)
#if __STDC_VERSION__ >= 199900L || __cplusplus >= 201103L || !defined(__STRICT_ANSI__)
#define va_copy(dest, src) __builtin_va_copy(dest, src)
#endif
#else
#ifdef __TARGET_ARCH_AARCH64
typedef struct __va_list {
void *__stack;
void *__gr_top;
void *__vr_top;
int __gr_offs;
int __vr_offs;
} va_list;
#else
typedef struct __va_list { void *__ap; } va_list;
#endif
va_start,va_end,va_arg()是定义其地址,及偏移地址。
核心部分代码
1.HAL库函数版本
void u3_printf(char* fmt,...)
{
u8 buffer[200];
u16 i;
va_list ap;
va_start(ap,fmt); //ap指向fmt的地址
i = vsprintf(buffer,fmt,ap); //vsprintf返回数组的长度
va_end(ap);
HAL_UART_Transmit(&huart3,(u8 *)buffer,i,0X00FF);
}
2.标准库函数版本
void u3_printf(char* fmt,...)
{
u16 i,j;
va_list ap;
va_start(ap,fmt);
vsprintf((char*)USART3_TX_BUF,fmt,ap);
va_end(ap);
i=strlen((const char*)USART3_TX_BUF); //得到数据长度
for(j=0;j<i;j++) //循环发送数据
{
while(USART_GetFlagStatus(USART3,USART_FLAG_TC)==RESET);
USART_SendData(USART3,USART3_TX_BUF[j]);
}
}
以HAL库为例,配置串口文件(直接可以拷贝引用)
/**
******************************************************************************
* File Name : USART.c
* Description : This file provides code for the configuration
* of the USART instances.
******************************************************************************
** This notice applies to any and all portions of this file
* that are not between comment pairs USER CODE BEGIN and
* USER CODE END. Other portions of this file, whether
* inserted by the user or by software development tools
* are owned by their respective copyright owners.
*
* COPYRIGHT(c) 2018 STMicroelectronics
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. Neither the name of STMicroelectronics nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
******************************************************************************
*/
/* Includes ------------------------------------------------------------------*/
#include "usart.h"
#include "gpio.h"
#include "time7.h"
/* USER CODE BEGIN 0 */
#include "stdarg.h"
#include "string.h"
#include "stdio.h"
/* USER CODE END 0 */
#ifdef __GNUC__
/* With GCC, small printf (option LD Linker->Libraries->Small printf
set to 'Yes') calls __io_putchar() */
#define PUTCHAR_PROTOTYPE int __io_putchar(int ch)
#else
#define PUTCHAR_PROTOTYPE int fputc(int ch, FILE *f)
#endif /* __GNUC__ */
UART_HandleTypeDef huart1;
UART_HandleTypeDef huart3;
/* USART1 init function */
void MX_USART1_UART_Init(void)
{
huart1.Instance = USART1;
huart1.Init.BaudRate = 115200;
huart1.Init.WordLength = UART_WORDLENGTH_8B;
huart1.Init.StopBits = UART_STOPBITS_1;
huart1.Init.Parity = UART_PARITY_NONE;
huart1.Init.Mode = UART_MODE_TX_RX;
huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;
huart1.Init.OverSampling = UART_OVERSAMPLING_16;
if (HAL_UART_Init(&huart1) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}
}
/* USART3 init function */
void MX_USART3_UART_Init(void)
{
huart3.Instance = USART3;
huart3.Init.BaudRate = 115200;
huart3.Init.WordLength = UART_WORDLENGTH_8B;
huart3.Init.StopBits = UART_STOPBITS_1;
huart3.Init.Parity = UART_PARITY_NONE;
huart3.Init.Mode = UART_MODE_TX_RX;
huart3.Init.HwFlowCtl = UART_HWCONTROL_NONE;
huart3.Init.OverSampling = UART_OVERSAMPLING_16;
if (HAL_UART_Init(&huart3) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}
}
void HAL_UART_MspInit(UART_HandleTypeDef* uartHandle)
{
GPIO_InitTypeDef GPIO_InitStruct;
if(uartHandle->Instance==USART1)
{
/* USER CODE BEGIN USART1_MspInit 0 */
/* USER CODE END USART1_MspInit 0 */
/* USART1 clock enable */
__HAL_RCC_USART1_CLK_ENABLE();
/**USART1 GPIO Configuration
PA9 ------> USART1_TX
PA10 ------> USART1_RX
*/
GPIO_InitStruct.Pin = GPIO_PIN_9;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
GPIO_InitStruct.Pin = GPIO_PIN_10;
GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
GPIO_InitStruct.Pull = GPIO_NOPULL;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
/* USART1 interrupt Init */
HAL_NVIC_SetPriority(USART1_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(USART1_IRQn);
/* USER CODE BEGIN USART1_MspInit 1 */
/* USER CODE END USART1_MspInit 1 */
}
else if(uartHandle->Instance==USART3)
{
/* USER CODE BEGIN USART3_MspInit 0 */
/* USER CODE END USART3_MspInit 0 */
/* USART3 clock enable */
__HAL_RCC_USART3_CLK_ENABLE();
/**USART3 GPIO Configuration
PB10 ------> USART3_TX
PB11 ------> USART3_RX
*/
GPIO_InitStruct.Pin = GPIO_PIN_10;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
GPIO_InitStruct.Pin = GPIO_PIN_11;
GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
GPIO_InitStruct.Pull = GPIO_NOPULL;
HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
/* USART3 interrupt Init */
__HAL_UART_ENABLE_IT(&huart3,UART_IT_RXNE);
HAL_NVIC_SetPriority(USART3_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(USART3_IRQn);
TIM7_Int_Init(1000-1,9000-1);
USART3_RX_STA=0;
TIM7->CR1&=~(1<<0);
/* USER CODE BEGIN USART3_MspInit 1 */
/* USER CODE END USART3_MspInit 1 */
}
}
void HAL_UART_MspDeInit(UART_HandleTypeDef* uartHandle)
{
if(uartHandle->Instance==USART1)
{
/* USER CODE BEGIN USART1_MspDeInit 0 */
/* USER CODE END USART1_MspDeInit 0 */
/* Peripheral clock disable */
__HAL_RCC_USART1_CLK_DISABLE();
/**USART1 GPIO Configuration
PA9 ------> USART1_TX
PA10 ------> USART1_RX
*/
HAL_GPIO_DeInit(GPIOA, GPIO_PIN_9|GPIO_PIN_10);
/* USART1 interrupt Deinit */
HAL_NVIC_DisableIRQ(USART1_IRQn);
/* USER CODE BEGIN USART1_MspDeInit 1 */
/* USER CODE END USART1_MspDeInit 1 */
}
else if(uartHandle->Instance==USART3)
{
/* USER CODE BEGIN USART3_MspDeInit 0 */
/* USER CODE END USART3_MspDeInit 0 */
/* Peripheral clock disable */
__HAL_RCC_USART3_CLK_DISABLE();
/**USART3 GPIO Configuration
PB10 ------> USART3_TX
PB11 ------> USART3_RX
*/
HAL_GPIO_DeInit(GPIOB, GPIO_PIN_10|GPIO_PIN_11);
/* USART3 interrupt Deinit */
HAL_NVIC_DisableIRQ(USART3_IRQn);
/* USER CODE BEGIN USART3_MspDeInit 1 */
/* USER CODE END USART3_MspDeInit 1 */
}
}
/* USER CODE BEGIN 1 */
PUTCHAR_PROTOTYPE
{
/* Place your implementation of fputc here */
/* e.g. write a character to the USART2 and Loop until the end of transmission */
HAL_UART_Transmit(&huart1, (uint8_t *)&ch, 1, 0xFFFF);
return ch;
}
void u3_printf(char* fmt,...)
{
u8 buffer[200];
u16 i;
va_list ap;
va_start(ap,fmt);
i = vsprintf(buffer,fmt,ap);
va_end(ap);
HAL_UART_Transmit(&huart3,(u8 *)buffer,i,0X00FF);
}
/* USER CODE END 1 */
/**
* @}
*/
/**
* @}
*/
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
由于printf为发送函数,在串口的中断处理函数中。可根据实际情况编写接受程序。