Micropython TMC2130 control script for a simple variable speed turntable, used on an ESP32. Docs for registry values at https://www.trinamic.com/fileadmin/assets/Products/ICs_Documents/TMC2130_datasheet.pdf

main.py

import machine
from machine import Pin, SPI, PWM, ADC
import time
import struct
import sys

# for use with TMC2130

led = Pin(13, Pin.OUT)
enable = Pin(32, Pin.OUT)
switch = Pin(33, Pin.IN, Pin.PULL_UP)

cs = Pin(4, Pin.OUT)
cs.value(1)

step = PWM(Pin(14))

spi = SPI(-1,baudrate=100000,polarity=1,phase=1,firstbit=SPI.MSB, sck=Pin(5, Pin.OUT), mosi=Pin(18, Pin.OUT), miso=Pin(19, Pin.IN))

speed = ADC(Pin(36))
speed.atten(ADC.ATTN_11DB)
speed.width(ADC.WIDTH_10BIT)
# /2 because dedge enabled
RPS = 51200/2

WRITE_FLAG = 0x80 #write flag
READ_FLAG =  0x00 #read flag
REG_GCONF = 0x00
REG_GSTAT = 0x01
REG_IHOLD_IRUN = 0x10
REG_CHOPCONF = 0x6C
REG_COOLCONF = 0x6D
REG_DCCTRL = 0x6E
REG_DRVSTATUS = 0x6F

def pack_data(data,fmt='>L'):
    pb = struct.pack(fmt,data)
    buf = bytearray(pb)
    return buf


def tmc_write(cmd, data):
    cs.value(0)
    cmdpack =  pack_data(cmd,'B')
    datapack = pack_data(data,'>L')
    c = spi.write(cmdpack)
    s = spi.write(datapack)
    cs.value(1)
    return s


def tmc_read(addr):
    cs.value(0)
    tmc_write(addr,0x00)
    s = spi.write(pack_data(addr))
    buf = struct.unpack('>L',spi.read(4,0x00))
    cs.value(1)
    return (s,buf)

def setup():
    spi.init(baudrate=100000)

    enable.value(1)
    #voltage on AIN is current reference
    s = tmc_write(WRITE_FLAG+REG_GCONF, 0x00000001)
    print(parse_status(s))
    #IHOLD=0x10, IRUN=0x10
    s = tmc_write(WRITE_FLAG+REG_IHOLD_IRUN, 0x00001010)
    print(parse_status(s))
    #native 256 microsteps, MRES=0, TBL=1=24, TOFF=8
    s = tmc_write(WRITE_FLAG+REG_CHOPCONF, 0x20008008)
    #64 microsteps, MRES=0, TBL=1=24, TOFF=8
    #s = tmc_write(WRITE_FLAG+REG_CHOPCONF,   0x02008008)
    #1 microsteps, MRES=0, TBL=1=24, TOFF=8
    #s = tmc_write(WRITE_FLAG+REG_CHOPCONF,   0x13008008)
    print(parse_status(s))

def flash(num):
    #esp32 doesn't have lots of fancy LEDs on the board
    #connect some LEDs later to show externally
    for i in range(num):
        led.value(1)
        time.sleep(.250)
        led.value(0)
        time.sleep(.250)


def error(num,e):
    while True:
        for i in range(num):
            led.value(1)
            time.sleep(.125)
            led.value(0)
            time.sleep(.125)
        print(e)
        sys.print_exception(e)
        time.sleep(4.000)

def parse_status(s):
    if s:
        if (s & 0x01):
            return("reset")
        elif (s & 0x02):
            return("error")
        elif (s & 0x03):
            return("sg2")
        elif (s & 0x04):
            return("standstill")
        else:
            return(s)
    else:
        return s


def speedsel(val):
    if val > 50:
        if val < 200:
            # 6RPM
            return int(RPS/10)
        elif val < 400:
            # 12RPM
            return int(RPS/5)
        elif val < 600:
            #60RPM
            return int(RPS)
        else:
            #120RPM
            return int(RPS*2)
    else:
        return 1

def run():
    try:
        print("enabling")
        enable.value(0)
        s, data = tmc_read(REG_GSTAT)
        goutput = "REG_GSTAT: "+ str(data[0]) + " " + str(parse_status(data[0]))
        print(goutput)
        s, data = tmc_read(REG_GCONF)
        coutput = "REG_GCONF: "+ str(data[0]) + " " + str(parse_status(data[0]))
        print(coutput)
        s, data = tmc_read(REG_DRVSTATUS)
        doutput = "DRVSTATUS: "+ str(data[0]) + " " + str(parse_status(data[0]))
        print(doutput)
        print(speed.read())
        revs = speedsel(speed.read())
        step.init(freq=revs)

        while revs > 1:
            if revs is not speedsel(speed.read()):
                revs = speedsel(speed.read())
                step.freq(revs)

            time.sleep(0.25)
            print(speed.read())

        step.deinit()


        enable.value(1)
        print("disabling")

    except Exception as e:
        enable.value(1)
        error(5,e)

def wait():
    flash(4)
    while True:
        if not switch.value():
            if speedsel(speed.read()) > 1:
                run()
                time.sleep(.5)
            else:
                print('speed at idle')
        else:
            print("switch off")
            flash(1)

if __name__ == "__main__":
    try:
        setup()
        wait()
    except Exception as e:
        enable.value(1)
        error(3,e)