st-spin 0.0.0.6

Interface for ST SpinFamily motor drivers

ST Spin Family Interface

A Python library for interfacing with ST Spin Family devices, specifically the ST Micro L6470, L6472, L6474, and L6480 ICs. Can be used nearly without modification with similar ICs.

Currently this project relies on spidev's SPI transfer function.

Meant for use in embedded Linux applictions. Python 3.6 or greater recommended.

Getting Started

pip install st-spin

Add imports

import time  # Used in our example

from stspin import (
    SpinChain,
    SpinDevice,
    Constant as StConstant,
    Register as StRegister,
    utility,
)

Create a device chain

stChain = SpinChain(
    total_devices=2,
    spi_select=(0, 0),
)

This assumes the spi device is at 0, 0.

Create devices

motorMain = stChain.create(1)
motorAux = stChain.create(0)

# Unless you absolutely need holding current,
# it is good practice to disable the power bridges
motorMain.hiZHard()
motorAux.hiZHard()

Run basic commands

motorMain.setRegister(StRegister.SpeedMax, 0x22)

motorMain.run(100)
time.sleep(3)
motorMain.hiZSoft()
time.sleep(1)

# {{{ Set some registers
motorMain.setRegister(StRegister.Acc, 0x5)
motorMain.setRegister(StRegister.Dec, 0x10)
motorAux.setRegister(StRegister.Acc, 0x20)
# }}}

# {{{ Go n steps with both motors
motorMain.move(steps=420000)
motorAux.move(steps=420000)
while motorMain.isBusy():
    time.sleep(0.2)
# }}}

# {{{ Head back
motorMain.setDirection(StConstant.DirReverse)
motorMain.move(steps=420000)
while motorMain.isBusy():
    time.sleep(0.2)
# }}}

# Release holding current
motorAux.hiZHard()
motorMain.hiZHard()

More details

For details on the SPI setup, see create() in spin_chain.py. See example.py

Troubleshooting

getStatus() is your friend. Feel free to use getPrettyStatus() under utility.py. The manual is also your friend.

Q: Why is my motor stalling, loud, or both? Most likely the Back-EMF compensation is not configured properly. The correction parameters depend heavily on your motor's ke value (V/Hz), inductance, and phase resistance.

After calculating the parameters using the manufacturer's tool, set KvalAcc, SpeedInt, SlpSt, etc. using setRegister().