STM32 舵機控制器

這節的內容將為大家介紹用stm32單片機做一個舵機控制器，通過旋轉電位器，來控制舵機的輸出角度，

老規矩，先將原始碼工程拿出來跟大家一同分享，

關注微信公眾號：廣乙電子（dlrcclub），回復關鍵字：舵機測驗儀，

在講原始碼之前我們先復習一下舵機的控制原理，在頻率50hz下，給一個0.5ms-2.5ms脈寬的占空比，就可以對舵機進行一個45°-180°的轉動，

通過單片機我們該如何實作呢？

1、配置ADC模塊，對電位器進行模擬量采集，將采集到的資料變成pwm需要輸出的占空比，

2、配置PWM模塊，產生一個頻率50Hz，脈寬在1ms-2.0ms的方波，

1ms-2.0ms對應的角度為45°-135°，

3、范圍轉換函式，電位器采集到的資料范圍為0-4096，而我們的PWM捕獲函式需要的值的范圍為1000-2000，因此，需要將0-4096的取值范圍轉換為1000-2000，

下面我們針對每一部分的函式進行列舉說明,ADC和PWM都是摘自原子stm32 例程的，也可以直接從例程中摘取，

ADC.c， adc部分基礎配置，

 #include "adc.h"
 #include "delay.h"
	   
//3?ê??ˉADC
//?aà??ò????ò?1??òí¨μà?aày
//?ò????è????a??í¨μà0~3																	   
void  Adc_Init(void)
{ 	
	ADC_InitTypeDef ADC_InitStructure; 
	GPIO_InitTypeDef GPIO_InitStructure;

	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA |RCC_APB2Periph_ADC1	, ENABLE );	  //ê1?üADC1í¨μàê±?ó
 

	RCC_ADCCLKConfig(RCC_PCLK2_Div6);   //éè??ADC·??μòò×ó6 72M/6=12,ADC×?′óê±??2??ü3?1y14M

	//PA1 ×÷?a?￡?aí¨μàê?è?òy??                         
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;		//?￡?aê?è?òy??
	GPIO_Init(GPIOA, &GPIO_InitStructure);	

	ADC_DeInit(ADC1);  //?′??ADC1,??íaéè ADC1 μ?è?2???′??÷??éè?aè±ê??μ  ADC1 ADC2 ADC3 

	ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;	//ADC1¤×÷?￡ê?:ADC1oíADC21¤×÷?ú?àá￠?￡ê?
	ADC_InitStructure.ADC_ScanConvMode = DISABLE;	//?￡êy×a??1¤×÷?úμ￥í¨μà?￡ê?
	ADC_InitStructure.ADC_ContinuousConvMode = DISABLE;	//?￡êy×a??1¤×÷?úμ￥′?×a???￡ê?
	ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;	//×a??óéèí?t??2?ê?ía2?′￥·￠???ˉ
	ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;	//ADCêy?Yóò????
	ADC_InitStructure.ADC_NbrOfChannel = 1;	//?3Dò??DD1??ò×a??μ?ADCí¨μàμ?êy??
	ADC_Init(ADC1, &ADC_InitStructure);	//?ù?YADC_InitStruct?D???¨μ?2?êy3?ê??ˉíaéèADCxμ???′??÷   

  
	ADC_Cmd(ADC1, ENABLE);	//ê1?ü???¨μ?ADC1
	
	ADC_ResetCalibration(ADC1);	//ê1?ü?′??D￡×?  
	 
	while(ADC_GetResetCalibrationStatus(ADC1));	//μè′y?′??D￡×??áê?
	
	ADC_StartCalibration(ADC1);	 //?a??ADD￡×?
 
	while(ADC_GetCalibrationStatus(ADC1));	 //μè′yD￡×??áê?
 
//	ADC_SoftwareStartConvCmd(ADC1, ENABLE);		//ê1?ü???¨μ?ADC1μ?èí?t×a?????ˉ1|?ü

}				  
//??μ?ADC?μ
//ch:í¨μà?μ 0~3
u16 Get_Adc(u8 ch)   
{
  	//éè?????¨ADCμ?1??ò×éí¨μà￡?ò???DòáD￡?2é?ùê±??     PB1??ó|ADC9
	ADC_RegularChannelConfig(ADC1, ch, 1, ADC_SampleTime_239Cycles5 );	//ADC1,ADCí¨μà,2é?ùê±???a239.5?ü?ú	  			    
  
	ADC_SoftwareStartConvCmd(ADC1, ENABLE);		//ê1?ü???¨μ?ADC1μ?èí?t×a?????ˉ1|?ü	
	 
	while(!ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC ));//μè′y×a???áê?

	return ADC_GetConversionValue(ADC1);	//·μ??×??üò?′?ADC11??ò×éμ?×a???á1?
}

u16 Get_Adc_Average(u8 ch,u8 times)
{
	u32 temp_val=0;
	u8 t;
	for(t=0;t<times;t++)
	{
		temp_val+=Get_Adc(ch);
		delay_ms(5);
	}
	return temp_val/times;
} 	 

PWM.c，PWM部分的基礎配置，

#include "pwm.h"



//PWMê?3?3?ê??ˉ
//arr￡o×??ˉ??×°?μ
//psc￡oê±?ó?¤·??μêy
void TIM1_PWM_Init(u16 arr,u16 psc)
{  
	 GPIO_InitTypeDef GPIO_InitStructure;
	TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
	TIM_OCInitTypeDef  TIM_OCInitStructure;

	RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);// 
 	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA , ENABLE);  //ê1?üGPIOíaéèê±?óê1?ü
	                                                                     	

   //éè????òy???a?′ó?ê?3?1|?ü,ê?3?TIM1 CH1μ?PWM??3?2¨D?
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8; //TIM_CH1
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;  //?′ó?í?íìê?3?
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_Init(GPIOA, &GPIO_InitStructure);

	
	TIM_TimeBaseStructure.TIM_Period = arr; //éè???ú??ò????üD?ê??t×°è????ˉμ?×??ˉ??×°????′??÷?ü?úμ??μ	 80K
	TIM_TimeBaseStructure.TIM_Prescaler =psc; //éè??ó?à′×÷?aTIMxê±?ó?μ?ê3yêyμ??¤·??μ?μ  2?·??μ
	TIM_TimeBaseStructure.TIM_ClockDivision = 0; //éè??ê±?ó·???:TDTS = Tck_tim
	TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  //TIM?òé???êy?￡ê?
	TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure); //?ù?YTIM_TimeBaseInitStruct?D???¨μ?2?êy3?ê??ˉTIMxμ?ê±???ùêyμ￥??

 
	TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2; //?????¨ê±?÷?￡ê?:TIM??3??í?èμ÷???￡ê?2
	TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //±è??ê?3?ê1?ü
	TIM_OCInitStructure.TIM_Pulse = 0; //éè??′y×°è?2???±è????′??÷μ???3??μ
	TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //ê?3???D?:TIMê?3?±è????D???
	TIM_OC1Init(TIM1, &TIM_OCInitStructure);  //?ù?YTIM_OCInitStruct?D???¨μ?2?êy3?ê??ˉíaéèTIMx

  TIM_CtrlPWMOutputs(TIM1,ENABLE);	//MOE ?÷ê?3?ê1?ü	

	TIM_OC1PreloadConfig(TIM1, TIM_OCPreload_Enable);  //CH1?¤×°??ê1?ü	 
	
	TIM_ARRPreloadConfig(TIM1, ENABLE); //ê1?üTIMx?úARRé?μ??¤×°????′??÷
	
	TIM_Cmd(TIM1, ENABLE);  //ê1?üTIM1
 
   
}

范圍轉換函式，個人覺得這個函式是整個工程的重點，希望大家能記住這個函式，這個函式是摘自arduino中的函式，記住便可熟練使用，

float map(float value,float fromLow,float fromHigh,float toLow,float toHigh)
{
	return ((value-fromLow)*(toHigh-toLow)/(fromHigh-fromLow)+toLow);
}

主函式 main.c

 int main(void)
 {	
	u16 pwmval_adc=0;    
	 
	u16 pwmval_to_range;
	
	
	//u8 adc_value;
	delay_init();	    	                      					//?óê±oˉêy3?ê??ˉ	  
	TIM1_PWM_Init(1999,719);                  					//Fre_PWM = 72000/(719+1)/(1999+1)=50hz
	uart_init(9600);                          
  Adc_Init();

	printf("this is a test");
  while(1)
	{
		//	printf("this is a test");
 		delay_ms(10);	 
		pwmval_adc = Get_Adc_Average(ADC_Channel_1,10);           //adcx ?a??è?μ? ADCμ??μ
		//printf("adc_value= %d \n\r",pwmval_adc);                     //′òó?3?ADC 2é?ˉμ?μ?μ????÷?μ   4090
		
		pwmval_to_range = (int)map(pwmval_adc,0,4092,1000,2000);
		delay_ms(100);
		printf("range =%d\t\r\n",pwmval_to_range);                           //ê?3? ?ú1000-2000·??§?ú×aíê·??§μ?ADC ?μ
		
		TIM_SetCompare1(TIM1,pwmval_to_range);
		
	} 
}

程式下載進去，我們就可以看到舵機按照45°-135°進行往復運動，

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