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STM32产生PWM是非常的方便的，要需要简单的设置定时器，即刻产生！ （1）使能定时器时钟：RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE); （2）定义相应的GPIO： /* PA2,3,4,5,6输出->Key_Up,Key_Down,Key_Left,Key_Right,Key_Ctrl */ GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2|GPIO_Pin_3|GPIO_Pin_4|GPIO_Pin_5|GPIO_Pin_6; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU; //下拉接地，检测输入的高电平 GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //50M时钟速度 GPIO_Init(GPIOA, &GPIO_InitStructure); /* PA7用于发出PWM波 */ GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //50M时钟速度 GPIO_Init(GPIOA, &GPIO_InitStructure); （3）如果是产生PWM（频率不变，占空比可变），记得打开PWM控制，在TIM_Configuration()中。 TIM_Cmd(TIM3,ENABLE); /* TIM1 Main Output Enable */ TIM_CtrlPWMOutputs(TIM1,ENABLE); 利用定时器产生不同频率的PWM有时候，需要产生不同频率的PWM，这个时候，设置与产生相同PWM的程序，有关键的不一样。 （一） 设置的原理 利用改变定时器输出比较通道的捕获值，当输出通道捕获值产生中断时，在中断中将捕获值改变，这时， 输出的I/O会产生一个电平翻转，利用这种办法，实现不同频率的PWM输出。 （二）关键设置 在定时器设置中：TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Disable); 在中断函数中： if (TIM_GetITStatus(TIM3, TIM_IT_CC2) != RESET) { TIM_ClearITPendingBit(TIM3, TIM_IT_CC2); capture = TIM_GetCapture2(TIM3); TIM_SetCompare2(TIM3, capture + Key_Value); } 一个定时器四个通道，分别产生不同频率（这个例子网上也有） vu16 CCR1_Val = 32768; vu16 CCR2_Val = 16384; vu16 CCR3_Val = 8192; vu16 CCR4_Val = 4096; void TIM_Configuration(void) { TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure; TIM_OCInitTypeDef TIM_OCInitStructure; /* TIM2 clock enable */ RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE); /* --------------------------------------------------------------- TIM2 Configuration: Output Compare Toggle Mode: TIM2CLK = 36 MHz, Prescaler = 0x2, TIM2 counter clock = 12 MHz CC1 update rate = TIM2 counter clock / CCR1_Val = 366.2 Hz CC2 update rate = TIM2 counter clock / CCR2_Val = 732.4 Hz CC3 update rate = TIM2 counter clock / CCR3_Val = 1464.8 Hz CC4 update rate = TIM2 counter clock / CCR4_Val = 2929.6 Hz --------------------------------------------------------------- */ /* Time base configuration */ TIM_TimeBaseStructure.TIM_Period = 65535; TIM_TimeBaseStructure.TIM_Prescaler = 2; TIM_TimeBaseStructure.TIM_ClockDivision = 0; TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure); /* Channel 1 Configuration in PWM mode */ TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Toggle; //PWM模式2 TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //正向通道有效 TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Disable;//反向通道无效 TIM_OCInitStructure.TIM_Pulse = CCR1_Val;//占空时间 TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low; //输出极性 TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_High; //互补端的极性 TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Set; TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCIdleState_Reset; TIM_OC1Init(TIM2,&TIM_OCInitStructure); //通道1 TIM_OC1PreloadConfig(TIM2, TIM_OCPreload_Disable);
TIM_OCInitStructure.TIM_Pulse = CCR2_Val; //占空时间 TIM_OC2Init(TIM2,&TIM_OCInitStructure);//通道2 TIM_OC2PreloadConfig(TIM2, TIM_OCPreload_Disable);
TIM_OCInitStructure.TIM_Pulse = CCR3_Val; //占空时间 TIM_OC3Init(TIM2,&TIM_OCInitStructure); //通道3 TIM_OC3PreloadConfig(TIM2, TIM_OCPreload_Disable);
TIM_OCInitStructure.TIM_Pulse = CCR4_Val; //占空时间 TIM_OC4Init(TIM2,&TIM_OCInitStructure);//通道4 TIM_OC4PreloadConfig(TIM2, TIM_OCPreload_Disable); /* TIM2 counter enable */ TIM_Cmd(TIM2,ENABLE);
/* TIM2 Main Output Enable */ //TIM_CtrlPWMOutputs(TIM2,ENABLE); /* TIM IT enable */ TIM_ITConfig(TIM2, TIM_IT_CC1 | TIM_IT_CC2 | TIM_IT_CC3 | TIM_IT_CC4, ENABLE); }
void GPIO_Configuration(void) { GPIO_InitTypeDef GPIO_InitStructure;
/*允许总线CLOCK,在使用GPIO之前必须允许相应端的时钟. 从STM32的设计角度上说,没被允许的端将不接入时钟,也就不会耗能, 这是STM32节能的一种技巧,*/
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE); RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE); RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE); RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOD, ENABLE);
/* PA2,3,4,5,6,7输出->LED1,LED2,LED3,LED4,LED5,LED6 */ GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2|GPIO_Pin_3|GPIO_Pin_4|GPIO_Pin_5|GPIO_Pin_6|GPIO_Pin_7; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD; //开漏输出 GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //50M时钟速度 GPIO_Init(GPIOA, &GPIO_InitStructure);
/* PB0,1输出->LED7,LED8*/ GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0|GPIO_Pin_1; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD; //开漏输出 GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //50M时钟速度 GPIO_Init(GPIOB, &GPIO_InitStructure);
/* PA0,1->KEY_LEFT,KEY_RIGHT*/ GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0|GPIO_Pin_1; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;? //上拉输入 GPIO_Init(GPIOA, &GPIO_InitStructure);
/* PC13->KEY_UP*/ GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;? //上拉输入 GPIO_Init(GPIOC, &GPIO_InitStructure);
/* PB5->KEY_DOWN*/ GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;? //上拉输入 GPIO_Init(GPIOB, &GPIO_InitStructure);
/* GPIOA Configuration:TIM2 Channel1, 2, 3 and 4 in Output */ GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_1 | GPIO_Pin_2 | GPIO_Pin_3; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA, &GPIO_InitStructure); }
void NVIC_Configuration(void) { NVIC_InitTypeDef NVIC_InitStructure;
/* Configure one bit for preemption priority */ NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);
NVIC_InitStructure.NVIC_IRQChannel=TIM2_IRQn; NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=0; NVIC_InitStructure.NVIC_IRQChannelSubPriority=1; NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE; NVIC_Init(&NVIC_InitStructure); }
u16 capture = 0; extern vu16 CCR1_Val; extern vu16 CCR2_Val; extern vu16 CCR3_Val; extern vu16 CCR4_Val; void TIM2_IRQHandler(void) { /* TIM2_CH1 toggling with frequency = 183.1 Hz */ if (TIM_GetITStatus(TIM2, TIM_IT_CC1) != RESET) { TIM_ClearITPendingBit(TIM2, TIM_IT_CC1 ); capture = TIM_GetCapture1(TIM2); TIM_SetCompare1(TIM2, capture + CCR1_Val ); } /* TIM2_CH2 toggling with frequency = 366.2 Hz */ if (TIM_GetITStatus(TIM2, TIM_IT_CC2) != RESET) { TIM_ClearITPendingBit(TIM2, TIM_IT_CC2); capture = TIM_GetCapture2(TIM2); TIM_SetCompare2(TIM2, capture + CCR2_Val); }
/* TIM2_CH3 toggling with frequency = 732.4 Hz */ if (TIM_GetITStatus(TIM2, TIM_IT_CC3) != RESET) { TIM_ClearITPendingBit(TIM2, TIM_IT_CC3); capture = TIM_GetCapture3(TIM2); TIM_SetCompare3(TIM2, capture + CCR3_Val); }
/* TIM2_CH4 toggling with frequency = 1464.8 Hz */ if (TIM_GetITStatus(TIM2, TIM_IT_CC4) != RESET) { TIM_ClearITPendingBit(TIM2, TIM_IT_CC4); capture = TIM_GetCapture4(TIM2); TIM_SetCompare4(TIM2, capture + CCR4_Val); }
} 一个定时器一个通道，产生不同频率
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