Speed regulation and stroke control based on Ti drv8424 driving stepper motor

Preface

I recently took over a project in the laboratory , Need to use TI Of DRV8424 Drive chip to drive a two-phase four wire stepping motor , The speed and motor stroke can be controlled , So I pondered for a few days , Successfully debugged ,MCU yes STM32F429.

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One 、 Stepper motor

1. Basic knowledge of

Stepping motor is a kind of motor that converts electric pulse signal into bit angular displacement or linear displacement , That is to say, when the motor receives a pulse, the motor rotates by an angle , This angle is called the step angle , The speed of the motor is only determined by the frequency of the pulse signal
According to magnetic excitation, stepping motors can be classified into ： Permanent magnet type , Reaction formula , Hybrid .
Divide according to the number of phases ： two-phase （ Two phase four wire ）, 3、 ... and / Four / Five phases （ Four phase five wire ）

Two 、 Stepper motor driver

1. The purpose of the drive

Due to the output of the single chip microcomputer PWM The signal cannot directly drive the stepping motor , Therefore, a driver is needed to amplify the output signal of the single chip microcomputer to drive the stepping motor , Stepping motor is mainly driven by subdivision , The step angle is subdivided by current distribution .
The static indexes of stepping motor are ： 1. Phase number ,2. Step angle ,3. Number of beats ,4. Positioning torque , Generally, the step angle of two phases is 1.8°. Three phases are 1.2°.
Dynamic indicators ：1. Step angle accuracy ,2. Maximum no-load starting frequency ,2. Maximum no-load operation frequency .

2.TI DRV8424 Stepping motor driver chip

Because the power and volume of the stepping motor are very small , So we used TI Of DRV8424 chip , It has integrated current sensing ,1/256 micro-stepping ,STEP/DIR Interface and intelligent tuning technology , Can pass PWM To achieve speed regulation , The working voltage is 4.5V to 33V, Up to... Can be driven 2.5A Full scale output current .

Pin description

AOUT1	winding A Output . Connected to the stepper motor winding .
AOUT2	winding A Output . Connected to the stepper motor winding .
PGND	Power grounding . Connect to system ground .
BOUT2	winding B Output . Connected to the stepper motor winding
BOUT1	winding B Output . Connected to the stepper motor winding
CPH	Charge pump switch node . stay CPH To CPL A rated voltage is connected between VM Of X7R 0.022uF Ceramic capacitor
CPL	ditto
DIR	Direction input . The logic level sets the step direction ; Internal pull-down resistance .
ENABLE	Logic low level will disable the device output ; Logic high level will enable ; Internal pull up to DVDD. It will also be decided OCP and OTSD The type of response
DVDD	Logic supply voltage . The passing capacitance is 0.47μ F to 1μ F、 The rated voltage is 6.3V or 10V Of X7R Ceramic capacitor connected to GND.
GND	Device grounding . Connect to system ground .
VREF	Current setting reference input . The maximum value is 3.3V（ about DRV8424） and 2.64V（ about DRV8425） . DVDD It can be used to provide... Through resistance voltage divider VREF.
M0	Micro step mode setting pin . Set step mode ; Internal pull-down resistor .
M1	Micro step mode setting pin . Set step mode ; Internal pull-down resistor .
DECAY0	Attenuation mode setting pin . Set attenuation mode
DECAY1	Attenuation mode setting pin . Set attenuation mode
STEP	Step input . The rising edge advances the divider one step ; Internal pull-down resistance .
VCP	Charge pump output . Through one X7R 0.22μ F 16V Ceramic capacitor connected to VM.
VM	Power Supply . Connect to the motor supply voltage , And through two 0.01µF Ceramic capacitors （ One per pin ） And a rated voltage of VM Large capacity capacitor bypass to PGND.
TOFF	Set the off time of attenuation mode during current chopping ; Four level pin . The ripple current in the intelligent tuning ripple control mode will also be set .
nFAULT	Fault indication . Fault status pull-down low logic low level ; Open drain output requires an external pull-up resistor .
nSLEEP	Sleep mode input . The logic high level is used to enable the device ; The logic low level is used to enter the low power sleep mode ; Internal pull-down resistance . nSLEEP A low level pulse will clear the fault .
PAD	Heat dissipation pad . Connect to system ground .

DIR– Direction control
STEP–MUC Of PWM
ENABLE–3.3V（ Enable motor ）,–0V（ close ）
nSLEEP–3.3V（ Cancel hibernation ）,–3V（ Sleep ）
About M0 and M1 It is used to set subdivision parameters


About DECAY0 and DECAY1 Used to set the attenuation mode , It is suggested to set it to （0.0） or （0,1）

3、 ... and . Code

The number of pulses determines the travel of the motor , The pulse frequency determines the speed of the motor , By looking up information, we know , It can be realized by setting the master-slave timer mode through two timers , Or use a timer , Direct timer interrupt changes the output level to analog pulse output , But if the motor is not closed-loop, it is easy to lose step , I use the master-slave timer mode to realize .

The square wave signal is output by the main timer , The slave timer counts the pulses output by the master timer , The interrupt service function of the slave timer is triggered when overflow . In order to control the number of turns of the stepping motor , The master-slave timer mode needs to be set according to the following table


This table is from STM32F4XX Chinese Reference Manual

Program ：
stepmotor.h

#ifndef __stepmotor_H
#define __stepmotor_H

#include "main.h"

void STEP_MOTOR_PWM_Configuration(u16 arr,u16 pre);// Master timer 

void TIM3_Config(u32 PulseNum_B );// From the timer 

void PWM_Output_B(u32 PulseNum_B,u8 DIR);			

void TIM3_IRQHandler(void);// Interrupt from timer 
#endif

# include "stepmotor.h"

//  Master timer TIM2, From the timer TIM3 ,ITR1.

void STEP_MOTOR_PWM_Configuration(u16 arr,u16 pre) // Main timer setting 
{
    
	GPIO_InitTypeDef GPIO_InitStructure;
	TIM_TimeBaseInitTypeDef	TIM_TimeBaseStructure;
	TIM_OCInitTypeDef TIM_OCInitStructure;
// TIM_BDTRInitTypeDef TIM_BDTRInitStructure;
	
	RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA | RCC_AHB1Periph_GPIOB | RCC_AHB1Periph_GPIOC | RCC_AHB1Periph_GPIOE, ENABLE);
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
	
	GPIO_PinAFConfig(GPIOA,GPIO_PinSource3,GPIO_AF_TIM2); //
	
	
	// PWM PA3
	GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_3;		 //
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
	GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; // Multiplexing push pull output 
	GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP; // Pull up 
	GPIO_Init(GPIOA,&GPIO_InitStructure); // initialization  PB14
	TIM_TimeBaseStructure.TIM_Period= arr-1;				
	TIM_TimeBaseStructure.TIM_Prescaler= pre-1;			
	TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up;
	TIM_TimeBaseStructure.TIM_ClockDivision=TIM_CKD_DIV1;		
	TIM_TimeBaseStructure.TIM_RepetitionCounter = 0; 
	TIM_TimeBaseInit(TIM2,&TIM_TimeBaseStructure);	 //TIM2
	 
	TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;				
	TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;	
	TIM_OCInitStructure.TIM_Pulse = arr/2;
	TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;		
						
	TIM_OC4Init(TIM2, &TIM_OCInitStructure);
	
	TIM_SelectMasterSlaveMode( TIM2, TIM_MasterSlaveMode_Enable);		//  Timer master-slave mode enable 
	TIM_SelectOutputTrigger( TIM2, TIM_TRGOSource_Update);
	
	TIM_OC4PreloadConfig(TIM2, TIM_OCPreload_Enable);

	TIM_ARRPreloadConfig(TIM2,ENABLE);		

void TIM3_Config(u32 PulseNum_B )// Set from the timer 
{
    
	TIM_TimeBaseInitTypeDef	TIM_TimeBaseStructure;
	NVIC_InitTypeDef	NVIC_InitStructure;
	
	RCC_APB1PeriphClockCmd( RCC_APB1Periph_TIM3, ENABLE);
	
	TIM_TimeBaseStructure.TIM_Period = PulseNum_B;
	TIM_TimeBaseStructure.TIM_Prescaler = 0;
	TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
	TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
	TIM_TimeBaseInit( TIM3, &TIM_TimeBaseStructure);
	
	
	TIM_SelectInputTrigger( TIM3, TIM_TS_ITR1);			// TIM2- Lord ,TIM3- from 
	TIM_SelectSlaveMode( TIM3, TIM_SlaveMode_Gated);
	TIM_ITConfig( TIM3, TIM_IT_Update, ENABLE);

	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_3);
	NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;
	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2;
	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;
	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
	NVIC_Init( &NVIC_InitStructure);
}
void PWM_Output_B( u32 PulseNum_B,u8 DIR)			// TIM2- Lord ,TIM3- from 
{
    
	if(DIR == 0)
			GPIO_SetBits(GPIOC, GPIO_Pin_4);// C4--DIR
	else
			GPIO_ResetBits(GPIOC, GPIO_Pin_4);// C4--DIR

		
	TIM3_Config(PulseNum_B);
	TIM_Cmd( TIM3, ENABLE);
	TIM_ClearITPendingBit( TIM3, TIM_IT_Update);
	TIM_ITConfig( TIM3, TIM_IT_Update, ENABLE);
	STEP_MOTOR_PWM_Configuration( 1000,84);		//F429: The general timer is  84MHz,  so 84MHz / 84 = 1MHz
	TIM_Cmd( TIM2, ENABLE);
	void TIM3_IRQHandler(void)
{
    
	if (TIM_GetITStatus( TIM3, TIM_IT_Update) != RESET)
	{
    
		TIM_ClearITPendingBit( TIM3, TIM_IT_Update);			//  Clears the interrupt flag bit 
		TIM_Cmd( TIM2, DISABLE);			//  off timer 2
		TIM_Cmd( TIM3, DISABLE);			//  off timer 3
		TIM_ITConfig( TIM3, TIM_IT_Update, DISABLE);
	}
}
}

main.c

#include "stm32f4xx.h"
#include "usart.h"
#include "delay.h"
#include "main.h"

float motor_t;

int main(void)
{
    	
 	 SystemInit();
	start_up();
	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_3);
	TIM7_Init(TIM7_ARR,TIM7_PRE); /*  Master clock initialization  */
  	usart2_Config(100000);
	Can_Init();
	PID_Init();	
  	LED_Init();
	PWM_Configuration(40,84);// 50kHz=20 , 25KHz=40 // DC brushless motor 
	ENCODER_Configuration(12800); // Encoder 
	
	PWM_Output_B(10000,0); // Stepper motor  DIR:0- positive ,1- reverse ,
	

	while(1)
	{
    
		LOOP();
					
	}
	
}

Call once in the initialization program PWM_Output_B（） that will do .