*psc预分频器决定计数脉冲的频率arr自动重装载寄存器决定了多久是一个周期ccr捕获/比较寄存器决定占空比cnt计数器寄存器不能写只能读1在理解呼吸灯原理之前先了解一些基本公式1. 频率公式 PWM频率 定时器时钟频率 / (PSC 1) / (ARR 1)计数频率 定时器输入时钟 / (PSC 1) CCR 乘以计数单位 高电平持续的时间脉宽。 定时器时钟频率和定时器输入时钟都是一个东西表示72MHz2. 占空比公式 占空比 CCR / (ARR 1) × 100% 3. 分辨率公式 分辨率步数 ARR 1注意1000Hz就是1s1000次变化也就是1ms一个周期1s等于1000ms设置ARR,PSC,CCR一些基本的#include stm32f10x.h // Device header void PWM_Init(void) { RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE); RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE); // RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE); // GPIO_PinRemapConfig(GPIO_PartialRemap1_TIM2, ENABLE); // GPIO_PinRemapConfig(GPIO_Remap_SWJ_JTAGDisable, ENABLE); GPIO_InitTypeDef GPIO_InitStructure; GPIO_InitStructure.GPIO_Mode GPIO_Mode_AF_PP; GPIO_InitStructure.GPIO_Pin GPIO_Pin_0; //GPIO_Pin_15; GPIO_InitStructure.GPIO_Speed GPIO_Speed_50MHz; GPIO_Init(GPIOA, GPIO_InitStructure); TIM_InternalClockConfig(TIM2); TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure; TIM_TimeBaseInitStructure.TIM_ClockDivision TIM_CKD_DIV1; TIM_TimeBaseInitStructure.TIM_CounterMode TIM_CounterMode_Up; TIM_TimeBaseInitStructure.TIM_Period 100 - 1; //ARR TIM_TimeBaseInitStructure.TIM_Prescaler 720 - 1; //PSC TIM_TimeBaseInitStructure.TIM_RepetitionCounter 0; TIM_TimeBaseInit(TIM2, TIM_TimeBaseInitStructure); TIM_OCInitTypeDef TIM_OCInitStructure; TIM_OCStructInit(TIM_OCInitStructure); TIM_OCInitStructure.TIM_OCMode TIM_OCMode_PWM1; TIM_OCInitStructure.TIM_OCPolarity TIM_OCPolarity_High; TIM_OCInitStructure.TIM_OutputState TIM_OutputState_Enable; TIM_OCInitStructure.TIM_Pulse 0; //CCR TIM_OC1Init(TIM2, TIM_OCInitStructure); TIM_Cmd(TIM2, ENABLE); } void PWM_SetCompare1(uint16_t Compare) { TIM_SetCompare1(TIM2, Compare); }主函数#include stm32f10x.h // Device header #include Delay.h #include OLED.h #include PWM.h uint8_t i; int main(void) { OLED_Init(); PWM_Init(); while (1) { for (i 0; i 100; i) { PWM_SetCompare1(i); Delay_ms(10); } for (i 0; i 100; i) { PWM_SetCompare1(100 - i); Delay_ms(10); } } }实现效果实现逻辑执行PWM_Init函数使pscarrccr初始化执行PWM_SetCompare1修改ccr的值i越高占比就越高也就是慢慢变亮后面i减小也就是慢慢变暗。2在了解为什么可以驱动舵机之前先要知道所以舵机都遵循0.5ms 高电平 → 转到 0°1.5ms 高电平 → 转到 90°2.5ms 高电平 → 转到 180°标准舵机要求控制信号的频率固定为 50Hz设置基本pscarrccr#include stm32f10x.h // Device header void PWM_Init(void) { RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE); RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE); GPIO_InitTypeDef GPIO_InitStructure; GPIO_InitStructure.GPIO_Mode GPIO_Mode_AF_PP; GPIO_InitStructure.GPIO_Pin GPIO_Pin_1; GPIO_InitStructure.GPIO_Speed GPIO_Speed_50MHz; GPIO_Init(GPIOA, GPIO_InitStructure); TIM_InternalClockConfig(TIM2); TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure; TIM_TimeBaseInitStructure.TIM_ClockDivision TIM_CKD_DIV1; TIM_TimeBaseInitStructure.TIM_CounterMode TIM_CounterMode_Up; TIM_TimeBaseInitStructure.TIM_Period 20000 - 1; //ARR TIM_TimeBaseInitStructure.TIM_Prescaler 72 - 1; //PSC TIM_TimeBaseInitStructure.TIM_RepetitionCounter 0; TIM_TimeBaseInit(TIM2, TIM_TimeBaseInitStructure); TIM_OCInitTypeDef TIM_OCInitStructure; TIM_OCStructInit(TIM_OCInitStructure); TIM_OCInitStructure.TIM_OCMode TIM_OCMode_PWM1; TIM_OCInitStructure.TIM_OCPolarity TIM_OCPolarity_High; TIM_OCInitStructure.TIM_OutputState TIM_OutputState_Enable; TIM_OCInitStructure.TIM_Pulse 0; //CCR TIM_OC2Init(TIM2, TIM_OCInitStructure); TIM_Cmd(TIM2, ENABLE); } void PWM_SetCompare2(uint16_t Compare) { TIM_SetCompare2(TIM2, Compare); }设置映射关系#include stm32f10x.h // Device header #include PWM.h void Servo_Init(void) { PWM_Init(); } void Servo_SetAngle(float Angle) { PWM_SetCompare2(Angle / 180 * 2000 500); }SetCompare是得到CCR的值angle等于0时ccr等于500arr固定为2000计数单位为72MHz/721MHz/s即1微秒就是一个计数周期500乘计数单位为高电平持续时间也就是500微秒0.5msangle等于180时ccr等于2000arr固定为2000计数单位为72MHz/721MHz/s即1微秒就是一个计数周期2500乘计数单位为高电平持续时间也就是2500微秒2.5ms主函数逻辑#include stm32f10x.h // Device header #include Delay.h #include OLED.h #include Servo.h #include Key.h uint8_t KeyNum; float Angle; int main(void) { OLED_Init(); Servo_Init(); Key_Init(); OLED_ShowString(1, 1, Angle:); while (1) { KeyNum Key_GetNum(); if (KeyNum 1) { Angle 30; if (Angle 180) { Angle 0; } } Servo_SetAngle(Angle); OLED_ShowNum(1, 7, Angle, 3); } }当按下按钮时满足第一个if条件执行Servo_SetAngle函数舵机旋转30度当大于180度时回到0度。实现效果注意舵机不能无限转范围一般是0-180度。3在了解驱动电机之前需要知道1.人听到的永远是PWM的频率通过调整psc和arr使频率在20khz以上人就听不到了。2.oc控制的是引脚输出具体对应关系如下通道对应的 CCR 寄存器对应的 GPIO 引脚默认通道1OC1CCR1PA0通道2OC2CCR2PA1通道3OC3CCR3PA2通道4OC4CCR4PA3PWN文件#include stm32f10x.h // Device header void PWM_Init(void) { RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE); RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE); GPIO_InitTypeDef GPIO_InitStructure; GPIO_InitStructure.GPIO_Mode GPIO_Mode_AF_PP; GPIO_InitStructure.GPIO_Pin GPIO_Pin_2; GPIO_InitStructure.GPIO_Speed GPIO_Speed_50MHz; GPIO_Init(GPIOA, GPIO_InitStructure); TIM_InternalClockConfig(TIM2); TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure; TIM_TimeBaseInitStructure.TIM_ClockDivision TIM_CKD_DIV1; TIM_TimeBaseInitStructure.TIM_CounterMode TIM_CounterMode_Up; TIM_TimeBaseInitStructure.TIM_Period 100 - 1; //ARR TIM_TimeBaseInitStructure.TIM_Prescaler 36 - 1; //PSC TIM_TimeBaseInitStructure.TIM_RepetitionCounter 0; TIM_TimeBaseInit(TIM2, TIM_TimeBaseInitStructure); TIM_OCInitTypeDef TIM_OCInitStructure; TIM_OCStructInit(TIM_OCInitStructure); TIM_OCInitStructure.TIM_OCMode TIM_OCMode_PWM1; TIM_OCInitStructure.TIM_OCPolarity TIM_OCPolarity_High; TIM_OCInitStructure.TIM_OutputState TIM_OutputState_Enable; TIM_OCInitStructure.TIM_Pulse 0; //CCR TIM_OC3Init(TIM2, TIM_OCInitStructure); TIM_Cmd(TIM2, ENABLE); } void PWM_SetCompare3(uint16_t Compare) { TIM_SetCompare3(TIM2, Compare); }通过修改PSC使PWN频率在20kHz以上硬件模块motor文件#include stm32f10x.h // Device header #include PWM.h void Motor_Init(void) { RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE); GPIO_InitTypeDef GPIO_InitStructure; GPIO_InitStructure.GPIO_Mode GPIO_Mode_Out_PP; GPIO_InitStructure.GPIO_Pin GPIO_Pin_4 | GPIO_Pin_5; GPIO_InitStructure.GPIO_Speed GPIO_Speed_50MHz; GPIO_Init(GPIOA, GPIO_InitStructure); PWM_Init(); } void Motor_SetSpeed(int8_t Speed) { if (Speed 0) { GPIO_SetBits(GPIOA, GPIO_Pin_4); GPIO_ResetBits(GPIOA, GPIO_Pin_5); PWM_SetCompare3(Speed); } else { GPIO_ResetBits(GPIOA, GPIO_Pin_4); GPIO_SetBits(GPIOA, GPIO_Pin_5); PWM_SetCompare3(-Speed); } }pp表示推挽输出主动让cpu控制高低电平GPIO_Speed_50MHz表示最高承受上限是50MHz之所以设置成一个高电平另一个低电平就是因为电流方向驱动电机转起来了。主函数部分#include stm32f10x.h // Device header #include Delay.h #include OLED.h #include Motor.h #include Key.h uint8_t KeyNum; int8_t Speed; int main(void) { OLED_Init(); Motor_Init(); Key_Init(); OLED_ShowString(1, 1, Speed:); while (1) { KeyNum Key_GetNum(); if (KeyNum 1) { Speed 20; if (Speed 100) { Speed -100; } } Motor_SetSpeed(Speed); OLED_ShowSignedNum(1, 7, Speed, 3); } }实现逻辑当按下按钮speed加20全局变量未初始化自动赋值为0执行函数Motor_SetSpeed并将相应的引脚置高或低电平并将speed上传至ccr最后显示speed。如果speed超过100启动反转再按下就再加20并一样执行函数Motor_SetSpeed并将相应的引脚置高或低电平并将speed上传至ccr最后显示speed。一些小知识占空比越高转的就越快。这是因为平均电压高。当停的时候由于机械惯性会继续转所以取平均电压占空比越高平均电压越高电流越大速度就越快而呼吸灯是因为人的视觉停留所以占空比高才看出的慢慢变亮再慢慢变暗。实现效果
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