Help with Pololu DRV8711 Stepper Motor Driver

[Atom058]

Amgen - Thanks for your input. Yes, I have tried both Mode 0 and 1 with no luck. I have also tried reversing the SCS pin (low, shiftout, high as opposed to high, shiftout, low) and nothing there either. I still think there is something in one of the registers that I am not setting correctly...

[Atom058]

OK - Problem solved. I went to Pololu and got help from their tech folks and they helped me figure this out. In a nutshell, it had to do with how I was creating the CTRL and TORQUE registers and sending them out. If you want to see how that all played out, just go to this link: https://forum.pololu.com/t/using-a-d...c-pro/27792/13. Don't see any reason to re-hash it here. In any event, I am now able to set the registers and control my stepper nicely. Here is my updated code that should get you started. The Pololu PNs for these boards is 3730 and 3731. Enjoy!

'****************************************************************
'*  Name    : Pololu Stepper-DRV8711.BAS                        *
'*  Author  : Jeff Wheat                                        *
'*  Date    : 05/21/2025                                        *
'*  Version : 1.0                                               *
'*  Notes   : PIC16F876A                                        *
'*          : Uses Pololu 4&8A Driver Boards                    *
'****************************************************************
@ DEVICE HS_OSC
    DEFINE OSC 20

    ADCON1 = 7 ' Set PortA Pins as I/O pins    
       
    TRISA = 0
    TRISB = 0
    TRISC = %00001111
              
    ' Define the LCD Hookup parameters
    ' data pins D4-D7 are hooked to pins B.0-B.3, respectively
    define LCD_DREG     PORTB   'Data Port = PORTB
    define LCD_DBIT     0       'Data starting bit = 0
    define LCD_RSREG    PORTB   'Register Select Port = PORTB
    define LCD_RSBIT    7       'RS bit = PortB.7
    define LCD_EREG     PORTB   'Enable Port = PORTB
    Define LCD_EBIT     4       'Enable Bit = PortB.4
    define LCD_BITS     4       'LCD Bus Size = 4
    define LCD_LINES    2       'Number of lines on LCD
       
    MenuBtn     var     PORTC.0
    UpBtn       var     PORTC.2
    DnBtn       var     PORTC.1
    EnterBtn    var     PORTC.3

    DirPin  	var     PORTA.3
    StepPin 	var     PORTA.5
    SDATO       var     PORTA.1  'connect to SDATI pin on driver board
    SDATI       var     PORTA.2  'connect to SDATO pin on driver board
    SCLK        var     PORTA.0
    SCS         var     PORTC.7
    
    Icnt        var     word
    StepDelay	var	    word
    StepMode    var     byte
    NumSteps    var     word
    DataOut     var     word
    DataIn      var     word
    
    Line1       con     $80
    Line2       con     $C0
    
    LSBFirst    con     0
    MSBFirst    con     1
    
 '****************************************************************    
    low steppin
    low DirPin
    low SCS
    
    pause 500 
    LCDOUT $FE, 1 ' Clear LCD screen 
    pause 20
    
    lcdout $FE, line1, " Pololu Stepper "
    lcdout $FE, line2, " Board - DRV8711"

    pause 2000
    LCDOUT $FE, 1

    gosub InitStepper
    pause 50
    
'    Gosub ReadRegisters
'    Stop
    
    Numsteps = 4000
    StepDelay = 500 'uS between steps
    
'****************************************************************
Start:
    lcdout $FE, line1, "Dir = CW "
    
    low DIRpin 'CW
    for icnt = 1 to numsteps
        high stepPin
        pauseus 10
        low StepPin
        pauseus StepDelay
    next

    pause 1000
    lcdout $FE, line1, "Dir = CCW" 

    high DIRpin 'CCW
    for icnt = 1 to numsteps
        high steppin
        pauseus 10
        low Steppin
        pauseus StepDelay
    next
    
    pause 1000
    goto Start        
        
'****************************************************************
ReadRegisters:
    'Read CTRL register 000
    DataIn = 0
    DataOut = %1000  
    high SCS    
    Shiftout SDATO, SCLK, MSBFirst, [DataOut\4]      
    Shiftin SDATI, SCLK, MSBFirst, [DataIn\12]      
    low SCS  
    
    lcdout $FE, line1, bin DataIn  'Display result in binary
    
    'read TORQUE register 001
    DataIn = 0
    DataOut = %1001  
    high SCS    
    Shiftout SDATO, SCLK, MSBFirst, [DataOut\4]      
    Shiftin SDATI, SCLK, MSBFirst, [DataIn\12]      
    low SCS 
    
    lcdout $FE, line2, bin DataIn
          
    Return    
        
'****************************************************************
'****************************************************************
InitStepper:    
    'TORQUE Register - Set current to 1/2 max (2A for 36v4 and 4A for 36v8)
    '         BIT0              BIT15
    'DataOut = %0 001 0 000 11011111  
    DataOut = %0001000011011111      
    high SCS
    Shiftout SDATO, SCLK, MSBFirst, [DataOut\16]   
    low SCS
    
    'CTRL Register - Enable Motor
    'DataOut = %0 000 11 11 0 0010 0 0 1
    'DataOut = %0000111100000001  'full step
    DataOut = %0000111100001001   '1/2 step
    'DataOut = %0000111100010001  '1/4 step
    high SCS
    Shiftout SDATO, SCLK, MSBFirst, [DataOut\16]       
    low SCS 
          
    return
    
'****************************************************************
    end