STM32 - PWM learning notes

One 、 Can produce PWM Timer introduction

STM32 In addition to TIM6 and 7. Other timers can be used to generate PWM Output . One of the advanced timers TIM1 and TIM8 It can produce as many as 7 On the road PWM Output . And universal timers can also generate up to 4 On the road PWM Output .

Two 、 All the way PWM The corresponding channel

 

  3、 ... and 、 Related configuration

1、 Channels used IO Mouth configuration ( Configure according to the selected channel )

	// Configure output I/O Pin 
    // Set this pin to multiplex output function , Output TIM3 CH2 Of PWM Pulse shape 	GPIOB.5
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5; //TIM_CH2
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;  // Multiplexing push pull output 
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_Init(GPIOB, &GPIO_InitStructure);// initialization GPIO

 2、 Timer configuration

   // Timer configuration 
   // initialization TIM3
	TIM_TimeBaseStructure.TIM_Period = arr; // Set the value of the auto reload register cycle for the next update event load activity 
	TIM_TimeBaseStructure.TIM_Prescaler =psc; // Set as TIMx Prescaled value of clock frequency divisor  
	TIM_TimeBaseStructure.TIM_ClockDivision = 0; // Set the clock split :TDTS = Tck_tim
	TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  //TIM Upcount mode 
	TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure); // according to TIM_TimeBaseInitStruct The parameter specified in TIMx Unit of time base 

 3、PWM Output mode configuration

Among them, we mainly pay attention to the first 、 The third configuration .

The first configuration ：

TIM_OCInitStructure.TIM_OCMode =TIM_OCMode_PWM1   /  TIM_OCMode_PWM2;

Configure the output comparison mode , When it comes to PWM1 when ： The current value of the counter Output the effective level when it is lower than the set value

                                 When it comes to PWM2 when ： The current value of the counter Output the effective level when it is higher than the set value

The third configuration ：

TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;

Configure whether the effective level is high level or low level ,TIM_OCPolarity_High： The active level is high

                                                          TIM_OCPolarity_Low： The active level is low

    // Timer channel configuration 
	// initialization TIM3 Channel2 PWM Pattern 	 
	TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2; // Select timer mode :TIM Pulse width modulation mode 2( Model 2 ： When counting, when the counter value exceeds the set value, the effective level is output , Output invalid level when it is lower than )
 	TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; // Compare output enable 
	TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; // Output polarity :TIM High output polarity ( The high level is the effective level , Or is the low level the effective level )
	TIM_OC2Init(TIM3, &TIM_OCInitStructure);  // according to T The specified parameter initializes the peripheral TIM3 OC2

  Full configuration ：

void TIM3_PWM_Init(u16 arr,u16 psc)
{  
	GPIO_InitTypeDef GPIO_InitStructure;
	TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
	TIM_OCInitTypeDef  TIM_OCInitStructure;
	
	
  // Clock configuration 
	RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);	// Enable timer 3 The clock 
 	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB  | RCC_APB2Periph_AFIO, ENABLE);  // Can make GPIO Peripherals and AFIO Multiplexing function module clock 
	
	// Remap 
	GPIO_PinRemapConfig(GPIO_PartialRemap_TIM3, ENABLE); //Timer3 Partial remapping   TIM3_CH2->PB5    
 
	
	// Configure output I/O Pin 
  // Set this pin to multiplex output function , Output TIM3 CH2 Of PWM Pulse shape 	GPIOB.5
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5; //TIM_CH2
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;  // Multiplexing push pull output 
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_Init(GPIOB, &GPIO_InitStructure);// initialization GPIO
 
	
	// Timer configuration 
   // initialization TIM3
	TIM_TimeBaseStructure.TIM_Period = arr; // Set the value of the auto reload register cycle for the next update event load activity 
	TIM_TimeBaseStructure.TIM_Prescaler =psc; // Set as TIMx Prescaled value of clock frequency divisor  
	TIM_TimeBaseStructure.TIM_ClockDivision = 0; // Set the clock split :TDTS = Tck_tim
	TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  //TIM Upcount mode 
	TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure); // according to TIM_TimeBaseInitStruct The parameter specified in TIMx Unit of time base 
	
	
	// Timer channel configuration 
	// initialization TIM3 Channel2 PWM Pattern 	 
	TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2; // Select timer mode :TIM Pulse width modulation mode 2( Model 2 ： When counting, when the counter value exceeds the set value, the effective level is output , Output invalid level when it is lower than )
 	TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; // Compare output enable 
	TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; // Output polarity :TIM High output polarity ( The high level is the effective level , Or is the low level the effective level )
	TIM_OC2Init(TIM3, &TIM_OCInitStructure);  // according to T The specified parameter initializes the peripheral TIM3 OC2

  TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable);  // Can make TIM3 stay CCR2 Pre loaded registers on ( effect : When changing the duty cycle , Can it take effect immediately )
 
	TIM_Cmd(TIM3, ENABLE);  // Can make TIM3
	

}