来一波不同凡响的PWM
话不多说 直接上代码 我的平台是 stm32F407VGT6 PA0 输出 使用定时器TIM2
//编程输出可调的硬件PWM，频率范围1Hz - 1MHz，占空比0 - 100 %uint32_t TIM2_PWM_FQ = 50; /* TIM2_CH1_PWM输出 频率设置值，1-1000000 */uint32_t TIM2_PWM_FQ_Old = 0;uint16_t TIM2_PWM_Pulse = 50;/* TIM2_CH1_PWM输出 占空比设置值，0-100 */uint16_t TIM2_PWM_Pulse_Old = 0;uint32_t SystemCoreClock = 168000000;/** 函数功能: 定时器4配置为硬件PWM模式(不开启TIM2的定时及DMA传输中断)* TIM2_PWM_FQ:TIM2_CH1_PWM 频率 1Hz至1000000Hz* TIM2_PWM_Pulse: TIM2_CH1_PWM 占空比 0-100%*/void StdPeriph_TIM2_PWM_Config(void){GPIO_InitTypeDef GPIO_InitStructure;TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;TIM_OCInitTypeDef TIM_OCInitStructure;uint32_t temp32;uint32_t uhTimerfrequency;uint16_t uhTimerPeriod;uint16_t uhTimerPulse;RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE); RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);// GPIOB ConfigurationGPIO_InitStruct.GPIO_Pin = GPIO_Pin_0;GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_DOWN;GPIO_InitStruct.GPIO_Speed = GPIO_Speed_100MHz;GPIO_Init(GPIOA, &GPIO_InitStruct);GPIO_PinAFConfig(GPIOA, GPIO_PinSource0, GPIO_AF_TIM2);uhTimerfrequency = 200000; /* 初始化 200KHz */temp32 = ((SystemCoreClock / 2) / uhTimerfrequency);if (temp32 > 65535) temp32 = 65535;uhTimerPeriod = (uint16_t) temp32;uhTimerPulse = uhTimerPeriod * 50 / 100; /* 占空比50% */// Time base configurationTIM_TimeBaseStructure.TIM_Period = uhTimerPeriod - 1; /* 0x0000 and 0xFFFF */TIM_TimeBaseStructure.TIM_Prescaler = 0; /* 0x0000 and 0xFFFF */TIM_TimeBaseStructure.TIM_ClockDivision = 0;TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);// PWM1 Mode configuration: Channel1TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2;TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;TIM_OCInitStructure.TIM_Pulse = uhTimerPulse;TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;TIM_OC1Init(TIM2, &TIM_OCInitStructure);TIM_OC1PreloadConfig(TIM2, TIM_OCPreload_Enable);TIM_ARRPreloadConfig(TIM2, ENABLE);TIM_GenerateEvent(TIM2, TIM_EventSource_Update);TIM_Cmd(TIM2, ENABLE);}/** 函数功能: 刷新TIM2_CH1_PWM输出的频率和占空比* 修改TIM2_PWM_FQ的值，调节PWM频率(1Hz至1MHz)* 修改TIM2_PWM_Pulse的值，调节PWM的占空比(0-100)*/void StdPeriph_TIM2_PWM_Update(void){uint32_t temp32;uint32_t uhTimerfrequency;uint16_t uhTimerPeriod;uint16_t uhTimerPrescaler;uint16_t uhTimerPulse;if ((TIM2_PWM_FQ_Old != TIM2_PWM_FQ) || (TIM2_PWM_Pulse_Old != TIM2_PWM_Pulse)) {TIM2_PWM_FQ_Old = TIM2_PWM_FQ;TIM2_PWM_Pulse_Old = TIM2_PWM_Pulse;if (TIM2_PWM_FQ >= 4000) {uhTimerfrequency = TIM2_PWM_FQ; /* 定时器计时频率和PWM频率相等 */uhTimerPrescaler = 1; /* 实际频率TIM2_PWM_FQ较大时，TIM2设置分频为1(不分频) */} else {uhTimerfrequency = 4000; /* 实际频率TIM2_PWM_FQ较小时，和4000Hz的频率比较，看相差几倍 */uhTimerPrescaler = 4000 / TIM2_PWM_FQ; /* 实际频率和4000相差的倍数作为TIM2的分频设置值 */uhTimerfrequency = uhTimerPrescaler * TIM2_PWM_FQ; /* TIM2分频后，计时周期变长，需要将uhTimerfrequency倍频 */}/* TIM2的周期要通过倍频uhTimerfrequency来计算,uhTimerPeriod = 84MHz / uhTimerfrequency */temp32 = ((SystemCoreClock / 2) / uhTimerfrequency);if (temp32 > 65535) temp32 = 65535;uhTimerPeriod = (uint16_t) temp32;if (TIM2_PWM_Pulse > 100) TIM2_PWM_Pulse = 100;uhTimerPulse = uhTimerPeriod * TIM2_PWM_Pulse / 100;TIM2->ARR = uhTimerPeriod - 1;TIM2->PSC = uhTimerPrescaler - 1;TIM2->CCR1 = uhTimerPulse;TIM2->EGR = TIM_PSCReloadMode_Update;}}
