文章目录[隐藏]

摘要

本文章基于国信长天M4开发板，讲述了STM32G4 定时器TIM输入捕获频率测量的应用，祝各位学生蓝桥杯比赛取得好成绩!

M4开发板频率发生器部分原理图

由上图可以看出，开发板上配置了两个555作为频率发生器，通过可调电阻R39，R40可调节输出频率，两个输出引脚分别连接在PA15和PB4引脚上。查阅芯片资料，可以得知这两个引脚可用作以下定时器的输入捕获：

PA15  --> TIM2_CH1(AF1)

PB4   --> TIM3_CH1(AF2)

TIM 输入捕获使用步骤

下面将基于硬件原厂提供的显示屏示例代码：HAL_06_LCD 介绍TIM频率捕获的使用步骤：

① 添加 stm32g4xx_hal_tim.c，stm32g4xx_hal_tim_ex.c

双击Drivers/STM32G4xx_HAL_Driver,打开添加文件对话框，在向上一级 -> Drivers -> STM32G4xx_HAL_Driver -> Src中，找到stm32g4xx_hal_tim.c 和 stm32g4xx_hal_tim_ex.c 并添加。添加后如下图所示：

② 修改 stm32g4xx_hal_conf.h 文件

在如下位置找到该文件，并打开：

取消注释 #define HAL_TIM_MODULE_ENABLED 这一行，取下注释后如下图所示：

③ main.c 添加#include "stm32g4xx_hal_tim.h"

在 main.c 适当位置添加#include "stm32g4xx_hal_tim.h"和#include "stdio.h"，添加后如下图所示：

④ 复制如下 TIM 初始化的代码

注意：下列代码包含了TIM2_CH1和TIM3_CH1的初始化，同学们按需复制！

TIM_HandleTypeDef htim2,htim3;
uint32_t  cc1_value_2 = 0;
uint32_t  f39 = 0, f40 = 0; //分别用来存储TIM2_CH1和TIM3_CH1的捕获频率

void HAL_TIM_IC_CaptureCallback(TIM_HandleTypeDef *htim)
{
	cc1_value_2 = __HAL_TIM_GET_COUNTER(htim);
	__HAL_TIM_SetCounter(htim,0);
	HAL_TIM_IC_Start_IT(htim, TIM_CHANNEL_1); //启动频率捕获
	
	if(htim == &htim2)
	{
		f40 = 1000000/cc1_value_2;
	}
	
	if(htim == &htim3)
	{
		f39 = 1000000/cc1_value_2;
	}
}

static void MX_TIM2_Init(void) //定时器2输入捕获初始化
{
	TIM_MasterConfigTypeDef sMasterConfig = {0};
	TIM_IC_InitTypeDef sConfigIC = {0};
	GPIO_InitTypeDef GPIO_InitStruct = {0};
	
	__HAL_RCC_TIM2_CLK_ENABLE();

	htim2.Instance = TIM2;
	htim2.Init.Prescaler = 80;
	htim2.Init.CounterMode = TIM_COUNTERMODE_UP;
	htim2.Init.Period = 0xFFFF;
	htim2.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
	htim2.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
	HAL_TIM_IC_Init(&htim2);
	
	sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
	sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
	HAL_TIMEx_MasterConfigSynchronization(&htim2, &sMasterConfig);
	sConfigIC.ICPolarity = TIM_INPUTCHANNELPOLARITY_RISING;
	sConfigIC.ICSelection = TIM_ICSELECTION_DIRECTTI;
	sConfigIC.ICPrescaler = TIM_ICPSC_DIV1;
	sConfigIC.ICFilter = 0;
	HAL_TIM_IC_ConfigChannel(&htim2, &sConfigIC, TIM_CHANNEL_1);
 
	GPIO_InitStruct.Pin = GPIO_PIN_15;
	GPIO_InitStruct.Mode = GPIO_MODE_AF_PP; //复用推挽输出
	GPIO_InitStruct.Pull = GPIO_NOPULL;
	GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
	GPIO_InitStruct.Alternate = GPIO_AF1_TIM2; //复用为定时器2
	HAL_GPIO_Init(GPIOA, &GPIO_InitStruct); //初始化PA15
	
	HAL_NVIC_SetPriority(TIM2_IRQn, 0, 0);
	HAL_NVIC_EnableIRQ(TIM2_IRQn);
	
	HAL_TIM_IC_Start_IT(&htim2, TIM_CHANNEL_1);//启动定时器2
}

void TIM2_IRQHandler(void) //定时器2中断
{
  HAL_TIM_IRQHandler(&htim2);
}


static void MX_TIM3_Init(void) //定时器3输入捕获初始化
{
	TIM_MasterConfigTypeDef sMasterConfig = {0};
	TIM_IC_InitTypeDef sConfigIC = {0};
	GPIO_InitTypeDef GPIO_InitStruct = {0};
	
	__HAL_RCC_TIM3_CLK_ENABLE();
	
	htim3.Instance = TIM3;
	htim3.Init.Prescaler = 80;
	htim3.Init.CounterMode = TIM_COUNTERMODE_UP;
	htim3.Init.Period = 0xFFFF;
	htim3.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
	htim3.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
	HAL_TIM_IC_Init(&htim3);
	
	sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
	sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
	HAL_TIMEx_MasterConfigSynchronization(&htim3, &sMasterConfig);
	
	sConfigIC.ICPolarity = TIM_INPUTCHANNELPOLARITY_RISING;
	sConfigIC.ICSelection = TIM_ICSELECTION_DIRECTTI;
	sConfigIC.ICPrescaler = TIM_ICPSC_DIV1;
	sConfigIC.ICFilter = 0;
	HAL_TIM_IC_ConfigChannel(&htim3, &sConfigIC, TIM_CHANNEL_1); //使用通道1
	
	GPIO_InitStruct.Pin = GPIO_PIN_4;
	GPIO_InitStruct.Mode = GPIO_MODE_AF_PP; //复用输出模式
	GPIO_InitStruct.Pull = GPIO_NOPULL;
	GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
	GPIO_InitStruct.Alternate = GPIO_AF2_TIM3; //复用为定时器3
	HAL_GPIO_Init(GPIOB, &GPIO_InitStruct); //初始化PA15
	
	HAL_NVIC_SetPriority(TIM3_IRQn, 0, 0);
	HAL_NVIC_EnableIRQ(TIM3_IRQn);
	
	HAL_TIM_IC_Start_IT(&htim3, TIM_CHANNEL_1); //启动定时器3
}

void TIM3_IRQHandler(void) //定时器3中断函数
{
  HAL_TIM_IRQHandler(&htim3);
}

⑤ 在main() 中调用 MX_TIM2_Init(); , MX_TIM3_Init();

如下图所示，在main() 函数的适当位置调用 MX_TIM2_Init(); , MX_TIM3_Init();

⑥ 获取捕获的频率

在main() 的while()中插入如下代码：

	char buf[64] = {0};
	
	sprintf(buf , "TIM2(R40): %d Hz   ", f40);
	LCD_DisplayStringLine(Line8, (uint8_t *)buf);
	
	sprintf(buf , "TIM3(R39): %dHz    ", f39);
	LCD_DisplayStringLine(Line9, (uint8_t *)buf);
	
	HAL_Delay(100);