Help with Pololu DRV8711 Stepper Motor Driver

[Atom058]

Hello - I am trying to write a simple program to run a stepper motor back and forth using the Pololu DRV8711 driver (Link: https://www.pololu.com/product/3730). In order to use the driver, you must first enable it and then you can use the DIR and Step Pins to run your stepper. With other drivers, all you needed to do was drive the ENABLE pin high and you were good to go. With the 8711 board, you have to enable it via SPI. This is done by sending 16-bit values to the registers on the board. Page 27 of the data sheet for this (Link: https://www.ti.com/lit/ds/symlink/drv8711.pdf) shows the registers and gives the default values. Technically, all I should have to do is to set bit 0 of the CTRL register to 1 and that should enable the motor, correct? I also want to limit the current to 1/2 of it's maximum value of 4A. This is done using the lower 8 bits of the TORQUE register. Here is my routine to do that:

'****************************************************************
InitStepper1:
    'Set current to 1/2 max (2A) 
    '$1180 = %0001000110000000
    high M1SCS
    Shiftout m1SDAT, M1SCLK, 1, [$1180/16]
    low M1SCS
    
    pause 50
    'Enable Motor
    '$0C11 = %0000110000010001
    high M1SCS
    Shiftout m1SDAT, M1SCLK, 1, [$0C11/16]
    low M1SCS    
    
    return
    
'****************************************************************

I am leaving all of the other values at their default. After executing the InitStepper1 code, I go to stepping the motor by pulsing the STEP pin and nothing happens. My stepper spins freely and I get no indication from my power supply that there is any additional current draw. Is there something I am not doing or doing wrong? Thanks! Jeff

[HenrikOlsson]

Looks like you're shifting out $1180 divided by 16, truncated to 8 bits, so $22. That's not what you want, is it?

Be careful with / vs \ ;-)

[Atom058]

THANKS! Good catch and yes, I feel stupid. I will give this a try and let you know if that was it! Jeff

[Atom058]

Well, While that was a problem, it was not THE problem. Still no movement. I tried both mode 1 and mode 0 for the SHIFTOUT methods, also, to no avail.
Here is a snip of the circuit board design for examination. It seems pretty straight forward, so I think my issue is with setting the registers. Any thoughts are appreciated.
NOTES: There are 2 drivers on board. Green traces = 5V, Blue = Gnd, Red = 12V, Black = Signal. PIC = PIC16F877A. Thanks!

[HenrikOlsson]

Hmm...PortA...have you disabled the analog functions (ADCON1 and CMCON registers, I believe)?
Have you verified (logic analyzer or scope) that the expected data does appears on the pins?