关键功能说明
PWM配置:
使用TIM1生成500Hz PWM信号
输出引脚:PA8 (TIM1_CH1)
计数器设置:预分频72-1 (1MHz时钟),周期1999 (500Hz)
初始占空比:50% (CCR=1000)
按键处理:
使用TIM2定时器中断实现按键扫描(10ms间隔)
UP键(PA0):增加占空比
DOWN键(PA1):减少占空比
按键消抖:30ms确认按下(3次扫描)
长按支持:按键保持按下时,每200ms触发一次调整
工作流程:
系统初始化后启动PWM输出
TIM2每10ms触发中断扫描按键状态
检测到按键按下时设置标志位
在定时器中断中更新PWM占空比
主循环处于低功耗状态(HAL_Delay)
硬件连接
MCU引脚 | 功能 | 连接目标 |
---|---|---|
PA8 | TIM1_CH1 | 电机驱动PWM输入 |
PA0 | GPIO输入 | UP按键(接GND) |
PA1 | GPIO输入 | DOWN按键(接GND) |
GND | 地 | 按键和电机共地 |
功能特点
精确的PWM控制:
500Hz PWM频率,适合多数直流电机控制
占空比范围:0-1999 (0-100%)
步进调整:10% (200步进值)
可靠的按键处理:
定时器中断扫描确保实时性
30ms消抖时间防止误触发
支持短按和长按操作
优化的系统结构:
中断处理保持主循环简洁
HAL库提供硬件抽象层
低功耗设计(主循环使用HAL_Delay)
使用说明
在STM32CubeIDE中创建工程
复制代码到main.c
配置TIM1为PWM输出,TIM2为基本定时器
配置PA0和PA1为输入模式
编译并烧录到STM32F103RC开发板
按UP/DOWN键调整电机速度
#include "stm32f1xx_hal.h"
// 全局变量
TIM_HandleTypeDef htim1;
TIM_HandleTypeDef htim2;
volatile uint16_t pwm_duty = 1000; // 初始占空比50%(ARR=1999)
volatile uint8_t key_up_flag = 0;
volatile uint8_t key_down_flag = 0;
// 系统时钟配置
void SystemClock_Config(void) {
RCC_OscInitTypeDef osc = {0};
RCC_ClkInitTypeDef clk = {0};
osc.OscillatorType = RCC_OSCILLATORTYPE_HSE;
osc.HSEState = RCC_HSE_ON;
osc.PLL.PLLState = RCC_PLL_ON;
osc.PLL.PLLSource = RCC_PLLSOURCE_HSE;
osc.PLL.PLLMUL = RCC_PLL_MUL9;
HAL_RCC_OscConfig(&osc);
clk.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
clk.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
clk.AHBCLKDivider = RCC_SYSCLK_DIV1;
clk.APB1CLKDivider = RCC_HCLK_DIV2;
clk.APB2CLKDivider = RCC_HCLK_DIV1;
HAL_RCC_ClockConfig(&clk, FLASH_LATENCY_2);
}
// TIM1 PWM初始化 (500Hz)
void MX_TIM1_Init(void) {
TIM_ClockConfigTypeDef sClockSourceConfig = {0};
TIM_MasterConfigTypeDef sMasterConfig = {0};
TIM_OC_InitTypeDef sConfigOC = {0};
TIM_BreakDeadTimeConfigTypeDef sBreakDeadTimeConfig = {0};
htim1.Instance = TIM1;
htim1.Init.Prescaler = 72 - 1; // 72MHz/72 = 1MHz
htim1.Init.CounterMode = TIM_COUNTERMODE_UP;
htim1.Init.Period = 1999; // 1MHz/2000 = 500Hz
htim1.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
htim1.Init.RepetitionCounter = 0;
htim1.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_ENABLE;
HAL_TIM_Base_Init(&htim1);
sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
HAL_TIM_ConfigClockSource(&htim1, &sClockSourceConfig);
HAL_TIM_PWM_Init(&htim1);
sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
HAL_TIMEx_MasterConfigSynchronization(&htim1, &sMasterConfig);
sConfigOC.OCMode = TIM_OCMODE_PWM1;
sConfigOC.Pulse = pwm_duty;
sConfigOC.OCPolarity = TIM_OCPOLARITY_HIGH;
sConfigOC.OCNPolarity = TIM_OCNPOLARITY_HIGH;
sConfigOC.OCFastMode = TIM_OCFAST_DISABLE;
sConfigOC.OCIdleState = TIM_OCIDLESTATE_RESET;
sConfigOC.OCNIdleState = TIM_OCNIDLESTATE_RESET;
HAL_TIM_PWM_ConfigChannel(&htim1, &sConfigOC, TIM_CHANNEL_1);
sBreakDeadTimeConfig.OffStateRunMode = TIM_OSSR_DISABLE;
sBreakDeadTimeConfig.OffStateIDLEMode = TIM_OSSI_DISABLE;
sBreakDeadTimeConfig.LockLevel = TIM_LOCKLEVEL_OFF;
sBreakDeadTimeConfig.DeadTime = 0;
sBreakDeadTimeConfig.BreakState = TIM_BREAK_DISABLE;
sBreakDeadTimeConfig.BreakPolarity = TIM_BREAKPOLARITY_HIGH;
sBreakDeadTimeConfig.AutomaticOutput = TIM_AUTOMATICOUTPUT_DISABLE;
HAL_TIMEx_ConfigBreakDeadTime(&htim1, &sBreakDeadTimeConfig);
// GPIO配置
GPIO_InitTypeDef GPIO_InitStruct = {0};
__HAL_RCC_GPIOA_CLK_ENABLE();
GPIO_InitStruct.Pin = GPIO_PIN_8;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
// 启动PWM
HAL_TIM_PWM_Start(&htim1, TIM_CHANNEL_1);
__HAL_TIM_SET_COMPARE(&htim1, TIM_CHANNEL_1, pwm_duty);
HAL_TIMEx_PWMN_Start(&htim1, TIM_CHANNEL_1);
__HAL_TIM_MOE_ENABLE(&htim1);
}
// TIM2 按键扫描定时器初始化 (10ms中断)
void MX_TIM2_Init(void) {
htim2.Instance = TIM2;
htim2.Init.Prescaler = 7200 - 1; // 72MHz/7200 = 10KHz
htim2.Init.CounterMode = TIM_COUNTERMODE_UP;
htim2.Init.Period = 100 - 1; // 10KHz/100 = 100Hz (10ms)
htim2.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
htim2.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_ENABLE;
HAL_TIM_Base_Init(&htim2);
HAL_TIM_Base_Start_IT(&htim2);
}
// GPIO初始化
void MX_GPIO_Init(void) {
// 按键配置 (PA0, PA1)
GPIO_InitTypeDef GPIO_InitStruct = {0};
__HAL_RCC_GPIOA_CLK_ENABLE();
// UP键 (PA0)
GPIO_InitStruct.Pin = GPIO_PIN_0;
GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
GPIO_InitStruct.Pull = GPIO_PULLUP;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
// DOWN键 (PA1)
GPIO_InitStruct.Pin = GPIO_PIN_1;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
}
// 按键扫描函数 (10ms调用一次)
void Key_Scan(void) {
static uint8_t up_key_cnt = 0;
static uint8_t down_key_cnt = 0;
// UP键扫描
if (HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_0) == GPIO_PIN_RESET) {
if (up_key_cnt < 20) up_key_cnt++; // 20*10ms = 200ms消抖+确认
if (up_key_cnt == 3) { // 30ms消抖后确认按下
key_up_flag = 1;
}
} else {
up_key_cnt = 0;
}
// DOWN键扫描
if (HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_1) == GPIO_PIN_RESET) {
if (down_key_cnt < 20) down_key_cnt++;
if (down_key_cnt == 3) {
key_down_flag = 1;
}
} else {
down_key_cnt = 0;
}
}
// 定时器中断回调
void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim) {
if (htim->Instance == TIM2) {
Key_Scan(); // 每10ms扫描一次按键
// 处理UP键
if (key_up_flag) {
if (pwm_duty < 1900) pwm_duty += 100; // 增加10%占空比
__HAL_TIM_SET_COMPARE(&htim1, TIM_CHANNEL_1, pwm_duty);
key_up_flag = 0;
}
// 处理DOWN键
if (key_down_flag) {
if (pwm_duty > 100) pwm_duty -= 100; // 减少10%占空比
__HAL_TIM_SET_COMPARE(&htim1, TIM_CHANNEL_1, pwm_duty);
key_down_flag = 0;
}
}
}
int main(void) {
HAL_Init();
SystemClock_Config();
MX_GPIO_Init();
MX_TIM1_Init();
MX_TIM2_Init();
while (1) {
// 主循环可添加其他任务
HAL_Delay(100);
}
}
// 中断处理函数
void TIM2_IRQHandler(void) {
HAL_TIM_IRQHandler(&htim2);
}