The below is a program for testing a stepper motor I wrote and not what I would release as a finished product by any means. No guarantee of use or that the code won’t break your system so apply at your own risk. This is provided for educational purposes only:
# copyright 2016 psionprime as registered user of pololu.com support forums
import sys
if sys.version_info < (3, 5):
raise "must use python 3.5 or greater"
else:
print("- python interpreter >= 3.5")
import gpiozero
from spidev import SpiDev
import time
import random
class AMIS30543_Controller():
def __init__(self, DO_STEP_PIN, DO_DIRECTION_PIN, DO_RESET_PIN, DI_FAULT_PIN):
"""
AMIS-30543 Stepper Controller Class
:param DO_STEP_PIN:
:param DO_DIRECTION_PIN:
:param DO_RESET_PIN:
:param DI_FAULT_PIN:
"""
# AMIS−30543 Registers & Command constants
self.REG = {
'WR': 0x00,
'CR0': 0x01,
'CR1': 0x02,
'CR2': 0x03,
'CR3': 0x09,
'SR0': 0x04,
'SR1': 0x05,
'SR2': 0x06,
'SR3': 0x07,
'SR4': 0x0A
}
self.CMD = {
'READ': 0x00,
'WRITE':0x80
}
# InitGPIO
self.DO_STEP = gpiozero.LED(DO_STEP_PIN)
self.DO_RESET = gpiozero.DigitalOutputDevice(DO_RESET_PIN)
self.DO_DIRECTION = gpiozero.DigitalOutputDevice(DO_DIRECTION_PIN)
self.DI_NO_FAULT = gpiozero.DigitalInputDevice(DI_FAULT_PIN)
self.spi = SpiDev()
self.spi.open(0, 0)
self.spi.max_speed_hz = 1000000
self.ResetStepper()
def __del__(self):
self.spi.close()
def ResetStepper(self):
self.DO_RESET.off() # must be off for AMIS to see reset
time.sleep(0.11)
self.DO_RESET.on()
time.sleep(0.11)
self.DO_RESET.off()
def StepIt(self):
# future note maybe use PWM for hopefully much more steady hardware pulses
if not self.DI_NO_FAULT:
return
self.DO_STEP.on()
time.sleep(0.0001)
self.DO_STEP.off()
def RegisterDump(self):
print("\nAMIS-30543 Registers\n")
# check stepper status
resp = self.spi.xfer2([self.CMD['READ'] | self.REG['WR'], 0])
print(" WR = ", bin(resp[1]), " ", str(resp[1]))
resp = self.spi.xfer2([self.CMD['READ'] | self.REG['CR0'], 0])
print("CR0 = ", bin(resp[1]), " ", str(resp[1]))
resp = self.spi.xfer2([self.CMD['READ'] | self.REG['CR1'], 0])
print("CR1 = ", bin(resp[1]), " ", str(resp[1]))
resp = self.spi.xfer2([self.CMD['READ'] | self.REG['CR2'], 0])
print("CR2 = ", bin(resp[1]), " ", str(resp[1]))
resp = self.spi.xfer2([self.CMD['READ'] | self.REG['CR3'], 0])
print("CR3 = ", bin(resp[1]), " ", str(resp[1]))
resp = self.spi.xfer2([self.CMD['READ'] | self.REG['SR0'], 0])
print("SR0 = ", bin(resp[1]), " ", str(resp[1]))
resp = self.spi.xfer2([self.CMD['READ'] | self.REG['SR1'], 0])
print("SR1 = ", bin(resp[1]), " ", str(resp[1]))
resp = self.spi.xfer2([self.CMD['READ'] | self.REG['SR2'], 0])
print("SR2 = ", bin(resp[1]), " ", str(resp[1]))
resp = self.spi.xfer2([self.CMD['READ'] | self.REG['SR3'], 0])
print("SR3 = ", bin(resp[1]), " ", str(resp[1]))
resp = self.spi.xfer2([self.CMD['READ'] | self.REG['SR4'], 0])
print("SR4 = ", bin(resp[1]), " ", str(resp[1]))
print("")
def ReverseBits(self, byte):
byte = ((byte & 0xF0) >> 4) | ((byte & 0x0F) << 4)
byte = ((byte & 0xCC) >> 2) | ((byte & 0x33) << 2)
byte = ((byte & 0xAA) >> 1) | ((byte & 0x55) << 1)
return byte
def test_RegisterRW(self):
self.ResetStepper()
self.spi.writebytes([self.CMD['WRITE'] | self.REG['WR'], 0b01111000])
self.spi.writebytes([self.CMD['WRITE'] | self.REG['CR0'], 0b11110011])
self.spi.writebytes([self.CMD['WRITE'] | self.REG['CR1'], 0b00100000])
self.spi.writebytes([self.CMD['WRITE'] | self.REG['CR2'], 0b00001000])
self.spi.writebytes([self.CMD['WRITE'] | self.REG['CR3'], 0b01000000])
if self.spi.xfer2([self.CMD['READ'] | self.REG['WR'], 0])[1] != 0b01111000:
print("Writing or reading self.REG['WR'] failed; driver power might be off.")
return False
if self.spi.xfer2([self.CMD['READ'] | self.REG['CR0'], 0])[1] != 0b11110011:
print("Writing or reading self.REG['CR0'] failed; driver power might be off.")
return False
if self.spi.xfer2([self.CMD['READ'] | self.REG['CR1'], 0])[1] != 0b00100000:
print("Writing or reading self.REG['CR1'] failed; driver power might be off.")
return False
if self.spi.xfer2([self.CMD['READ'] | self.REG['CR2'], 0])[1] != 0b00001000:
print("Writing or reading self.REG['CR2'] failed; driver power might be off.")
return False
if self.spi.xfer2([self.CMD['READ'] | self.REG['CR3'], 0])[1] != 0b01000000:
print("Writing or reading self.REG['CR3'] failed; driver power might be off.")
return False
self.RegisterDump()
print("test_RegisterRW Passed\n")
self.ResetStepper()
return True
def SetRegDefaults(self):
"""
Sets default values:
WR: no watchdog
CR0: 1/32 step & current limit to 1850mA
CR1: CW motion (depending on wiring) & step on rising edge
CR2: motor off & no sleep & SLA no transparent & SLA gain @ 0.5
CR3: no extended step mode
:return:
"""
self.ResetStepper()
self.spi.writebytes([self.CMD['WRITE'] | self.REG['WR'], 0b00000000])
self.spi.writebytes([self.CMD['WRITE'] | self.REG['CR0'], 0b00010011])
self.spi.writebytes([self.CMD['WRITE'] | self.REG['CR1'], 0b00000000])
self.spi.writebytes([self.CMD['WRITE'] | self.REG['CR2'], 0b00000000])
self.spi.writebytes([self.CMD['WRITE'] | self.REG['CR3'], 0b00000000])
if self.spi.xfer2([self.CMD['READ'] | self.REG['WR'], 0])[1] != 0b00000000:
print("Writing or reading self.REG['WR'] failed; driver power might be off.")
return False
if self.spi.xfer2([self.CMD['READ'] | self.REG['CR0'], 0])[1] != 0b00010011:
print("Writing or reading self.REG['CR0'] failed; driver power might be off.")
return False
if self.spi.xfer2([self.CMD['READ'] | self.REG['CR1'], 0])[1] != 0b00000000:
print("Writing or reading self.REG['CR1'] failed; driver power might be off.")
return False
if self.spi.xfer2([self.CMD['READ'] | self.REG['CR2'], 0])[1] != 0b00000000:
print("Writing or reading self.REG['CR2'] failed; driver power might be off.")
return False
if self.spi.xfer2([self.CMD['READ'] | self.REG['CR3'], 0])[1] != 0b00000000:
print("Writing or reading self.REG['CR3'] failed; driver power might be off.")
return False
self.RegisterDump()
print("Register Defaults Enabled\n")
return True
def SetMotorEnable(self):
"""
CR2: motor on & no sleep & SLA no transparent & SLA gain @ 0.5
:return:
"""
self.spi.writebytes([self.CMD['WRITE'] | self.REG['CR2'], 0b10000000])
if self.spi.xfer2([self.CMD['READ'] | self.REG['CR2'], 0])[1] != 0b10000000:
print("Writing or reading self.REG['CR2'] failed; driver power might be off.")
return False
def SetMotorDisable(self):
"""
CR2: motor on & no sleep & SLA no transparent & SLA gain @ 0.5
:return:
"""
self.spi.writebytes([self.CMD['WRITE'] | self.REG['CR2'], 0b00000000])
if self.spi.xfer2([self.CMD['READ'] | self.REG['CR2'], 0])[1] != 0b00000000:
print("Writing or reading self.REG['CR2'] failed; driver power might be off.")
return False
def SetDirPos(self):
"""
CR1: CW motion (depending on wiring) & step on rising edge
:return:
"""
self.spi.writebytes([self.CMD['WRITE'] | self.REG['CR1'], 0b00000000])
if self.spi.xfer2([self.CMD['READ'] | self.REG['CR1'], 0])[1] != 0b00000000:
print("Writing or reading self.REG['CR1'] failed; driver power might be off.")
return False
def SetDirNeg(self):
"""
CR1: CCW motion (depending on wiring) & step on rising edge
:return:
"""
self.spi.writebytes([self.CMD['WRITE'] | self.REG['CR1'], 0b10000000])
if self.spi.xfer2([self.CMD['READ'] | self.REG['CR1'], 0])[1] != 0b10000000:
print("Writing or reading self.REG['CR1'] failed; driver power might be off.")
return False
axis_X1 = AMIS30543_Controller(19, 26, 20, 21)
axis_X1.RegisterDump()
axis_X1.test_RegisterRW()
if not axis_X1.SetRegDefaults():
sys.exit("Failed to set register defaults")
axis_X1.SetMotorEnable()
# steps for 250mm = .3mm/step with GT2 2mm belt and 30 tooth pully and using 1/32 micro steps
steps = int(250 * ((200 * 32) / (2 * 30)))
print("\nStep Test for 250mm requires ", steps, " steps")
tStart = time.monotonic()
# long test to see if still running in morning
# add a little randomness to not land on the same spot the whole test and potentialy shorten the life of th motor
random.seed()
bToggle = True
while(True):
for step in range(int(steps + random.getrandbits(8))):
axis_X1.StepIt()
if not axis_X1.DI_NO_FAULT:
print("FAULT")
axis_X1.RegisterDump()
break
if bToggle:
axis_X1.SetDirNeg()
bToggle = False
else:
axis_X1.SetDirPos()
bToggle = True
# axis_X1.DO_STEP.blink(.000005, .000005, steps, False)
tEnd = time.monotonic()
print("\nStep Test took ", tEnd - tStart, " secs")
print("\nSpeed: ", 250 / (tEnd - tStart), " mm/sec\n")
axis_X1.SetMotorDisable()
