PWM The implementation of the

Hardware basis of single chip microcomputer and its counting principle

Universal timer

Add up the count （ Count up ）

Alternate counting

PWM Duty cycle setting

pwm.c

#include "pwm.h"


void TIM3_PWM_Init(u16 arr,u16 psc){
      //TIM3 PWM initialization  arr Reload value  psc The prescaled coefficients 
    GPIO_InitTypeDef     GPIO_InitStrue;
    TIM_OCInitTypeDef     TIM_OCInitStrue;
    TIM_TimeBaseInitTypeDef     TIM_TimeBaseInitStrue;
    
    // Turn on the timers separately ,GPIO Clock with multiplex interface 
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3,ENABLE);// Can make TIM3 And the related GPIO The clock 
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB,ENABLE);// Can make GPIOB The clock (LED stay PB0 Pin )
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO,ENABLE);// Can make AFIO The clock ( Timer 3 passageway 3 Need to remap to BP5 Pin )
    
    GPIO_InitStrue.GPIO_Pin=GPIO_Pin_0;     // TIM_CH3
    GPIO_InitStrue.GPIO_Mode=GPIO_Mode_AF_PP;    //  Reuse push pull 
    GPIO_InitStrue.GPIO_Speed=GPIO_Speed_50MHz;    // Set the maximum output speed 
    GPIO_Init(GPIOB,&GPIO_InitStrue);                //GPIO Port initialization settings 
    
// GPIO_PinRemapConfig(GPIO_PartialRemap_TIM3,ENABLE); // mapping , Remapping is only used for 64、100、144 Single chip microcomputer foot 
//  Remapping of reuse function generally refers to 
// “ When the corresponding pin is occupied , By setting remap RemapConfig To change the timer （ Or other equipment ） The value corresponding to the pin used ”
   // When there is no remapping ,TIM3 The four channels of CH1,CH2,CH3,CH4 They correspond to each other PA6,PA7,PB0,PB1
   // When partially remapped ,TIM3 The four channels of CH1,CH2,CH3,CH4 They correspond to each other PB4,PB5,PB0,PB1 (GPIO_PartialRemap_TIM3)
   // When completely remapped ,TIM3 The four channels of CH1,CH2,CH3,CH4 They correspond to each other PC6,PC7,PC8,PC9 (GPIO_FullRemap_TIM3) 
	      
    TIM_TimeBaseInitStrue.TIM_Period=arr;    // Set auto reload load value ( Count overflow value )
    TIM_TimeBaseInitStrue.TIM_Prescaler=psc;        // The prescaled coefficients （ Number of cycles of one frequency ）
    TIM_TimeBaseInitStrue.TIM_CounterMode=TIM_CounterMode_Up;    // The counter overflows up 
// #define TIM_CounterMode_Up ((uint16_t)0x0000)  Add up the count 
// #define TIM_CounterMode_Down ((uint16_t)0x0010)  Down / Decrement count 
// #define TIM_CounterMode_CenterAligned1 ((uint16_t)0x0020)  Alternate counting , And in ARR Overflow at 
// #define TIM_CounterMode_CenterAligned2 ((uint16_t)0x0040)  Alternate counting , And in CNT=0 Overflow at 
// #define TIM_CounterMode_CenterAligned3 ((uint16_t)0x0060)  Alternate counting , And in ARR and CNT=0 Overflow at 
    TIM_TimeBaseInitStrue.TIM_ClockDivision=TIM_CKD_DIV1;        // The division factor of the clock , It plays a little delay role , General set to TIM_CKD_DIV1（ Unstable use TIM_CKD_DIV2）
    TIM_TimeBaseInit(TIM3,&TIM_TimeBaseInitStrue);        //TIM3 Initialize settings ( Set up PWM The cycle of )
    
    TIM_OCInitStrue.TIM_OCMode=TIM_OCMode_PWM1;        // PWM Pattern 1:CNT < CCR Output effective level at 
// #define TIM_OCMode_Timing ((uint16_t)0x0000)
// #define TIM_OCMode_Active ((uint16_t)0x0010)
// #define TIM_OCMode_Inactive ((uint16_t)0x0020)
// #define TIM_OCMode_Toggle ((uint16_t)0x0030)
// #define TIM_OCMode_PWM1 ((uint16_t)0x0060)
// #define TIM_OCMode_PWM2 ((uint16_t)0x0070)
    TIM_OCInitStrue.TIM_OCPolarity=TIM_OCPolarity_High;//  Set polarity - The effective level is ： High level 
    TIM_OCInitStrue.TIM_OutputState=TIM_OutputState_Enable;//  Output enable 
    TIM_OC3Init(TIM3,&TIM_OCInitStrue);        //TIM3 The passage of 3 PWM  Mode setting 

    TIM_OC3PreloadConfig(TIM3,TIM_OCPreload_Enable);        // Enable preload register 
    
    TIM_Cmd(TIM3,ENABLE);        // Can make TIM3
    
}

 Set the clock 
 Set interface 
 The loading value in the structure , Frequency division coefficient and counting mode loading function 
 Set high / Low level active 
 Enable register and clock 

main.c Realize to SG90 The control of

int main (void){
    // The main program 
	delay_ms(500); // Wait for other devices to be ready when powered on 
	RCC_Configuration(); // System clock initialization  
	RELAY_Init();// Relay initialization 

	I2C_Configuration();//I2C initialization 
	OLED0561_Init(); //OLED initialization 
	OLED_DISPLAY_8x16_BUFFER(0," YoungTalk "); // display string 
	OLED_DISPLAY_8x16_BUFFER(3," SG90 TEST2 "); // display string 

	TOUCH_KEY_Init();// Key initialization 
	TIM3_PWM_Init(59999,23); // Set the frequency to 50Hz, Formula for ： Overflow time Tout（ Unit second ）=(arr+1)(psc+1)/Tclk 20MS = (59999+1)*(23+1)/72000000
                          //Tclk Clock for general timer , If APB1 There is no frequency division , Then it is the system clock ,72MHZ
                          //PWM clock frequency =72000000/(59999+1)*(23+1) = 50HZ (20ms), Set the auto load value 60000, The prescaled coefficients 24

	while(1){
    
		if(!GPIO_ReadInputDataBit(TOUCH_KEYPORT,TOUCH_KEY_A)){
     // Read the level of the touch button 
			OLED_DISPLAY_8x16_BUFFER(6," Angle 0 "); // display string 
			TIM_SetCompare3(TIM3,1500);        // Change the comparison value TIM3->CCR2 Achieve the effect of adjusting the duty cycle （1500 by 0 degree ）
			//void TIM_SetCompare3(TIM_TypeDef* TIMx, uint16_t Compare3) By setting Compare3 To set the duty cycle 

		}
		if(!GPIO_ReadInputDataBit(TOUCH_KEYPORT,TOUCH_KEY_B)){
     // Read the level of the touch button 
			OLED_DISPLAY_8x16_BUFFER(6," Angle 45 "); // display string 
			TIM_SetCompare3(TIM3,3000);        // Change the comparison value TIM3->CCR2 Achieve the effect of adjusting the duty cycle 
		}
		if(!GPIO_ReadInputDataBit(TOUCH_KEYPORT,TOUCH_KEY_C)){
     // Read the level of the touch button 
			OLED_DISPLAY_8x16_BUFFER(6," Angle 90 "); // display string 
			TIM_SetCompare3(TIM3,4500);        // Change the comparison value TIM3->CCR2 Achieve the effect of adjusting the duty cycle 
		}
		if(!GPIO_ReadInputDataBit(TOUCH_KEYPORT,TOUCH_KEY_D)){
     // Read the level of the touch button 
			OLED_DISPLAY_8x16_BUFFER(6," Angle 180 "); // display string 
			TIM_SetCompare3(TIM3,7500);        // Change the comparison value TIM3->CCR2 Achieve the effect of adjusting the duty cycle 
		}
	}
}