Qwiic_SCMD_Py¶

Python module for the qwiic motor driver

This python package is a port of the existing SparkFun Serial Controlled Motor Driver Arduino Library

This package can be used in conjunction with the overall SparkFun qwiic Python Package

New to qwiic? Take a look at the entire SparkFun qwiic ecosystem.

Supported Platforms¶

The qwiic Python package current supports the following platforms:

Dependencies¶

This driver package depends on the qwiic I2C driver: Qwiic_I2C_Py

Documentation¶

The SparkFun qwiic SCMD module documentation is hosted at ReadTheDocs

Installation¶

PyPi Installation¶

This repository is hosted on PyPi as the sparkfun-qwiic-scmd package. On systems that support PyPi installation via pip, this library is installed using the following commands

For all users (note: the user must have sudo privileges):

sudo pip install sparkfun-qwiic-scmd

For the current user:

pip install sparkfun-qwiic-scmd

Local Installation¶

To install, make sure the setuptools package is installed on the system.

Direct installation at the command line:

python setup.py install

To build a package for use with pip:

python setup.py sdist

A package file is built and placed in a subdirectory called dist. This package file can be installed using pip.

  cd dist
  pip install sparkfun_qwiic_scmd-<version>.tar.gz

Example Use

TBD

Table of Contents¶

API Reference¶

qwiic_scmd¶

Python module for the serial control motor driver.

This python package is a port of the existing [SparkFun Serial Controlled Motor Driver Arduino Library](https://github.com/sparkfun/SparkFun_Serial_Controlled_Motor_Driver_Arduino_Library)

This package can be used in conjunction with the overall [SparkFun qwiic Python Package](https://github.com/sparkfun/Qwiic_Py)

New to qwiic? Take a look at the entire [SparkFun qwiic ecosystem](https://www.sparkfun.com/qwiic).

class qwiic_scmd.QwiicScmd(address=None, i2c_driver=None)[source]¶

Parameters:	address – The I2C address to use for the device. If not provided, the default address is used. i2c_driver – An existing i2c driver object. If not provided a driver object is created.
Returns:	The Serial Control Motor Driver device object.
Return type:	Object

begin()[source]¶

Initialize the operation of the SCMD module

Returns:	Returns true of the initializtion was successful, otherwise False.
Return type:	bool

bridging_mode(driverNum, bridged)[source]¶

Configure a driver’s bridging state

Parameters:	driverNum – Number of driver. Master is 0, slave 1 is 1, etc. 0 to 16 bridged – 0 or 1 for forward and backward
Returns:	No return value

busy()[source]¶

Returns if the driver is busy

Returns:	busy status
Return type:	boolean

connected¶

Determine if a SCMD device is conntected to the system..

Returns:	True if the device is connected, otherwise False.
Return type:	bool

disable()[source]¶

Disable driver functions

Returns:	No return value

enable()[source]¶

Enable driver functions

Returns:	No return value

get_diagnostics()[source]¶

Get diagnostic information from the masterd

Returns:	Object returned with properties that are the diagnostic info
Return type:	Object - SCMDDiagnostics()

get_remote_diagnostics(address)[source]¶

Get diagnostic information from a slave

Parameters:	address – Address of slave to read. Can be 0x50 to 0x5F for slave 1 to 16.
Returns:	Object returned with properties that are the diagnostic info
Return type:	Object - SCMDDiagnostics()

inversion_mode(motorNum, polarity)[source]¶

Configure a motor’s direction inversion

Parameters:	motoNum – Motor number from 0 to 33 polarity – 0 or 1 for default or inverted
Returns:	No return value

is_connected()[source]¶

Determine if a SCMD device is conntected to the system..

Returns:	True if the device is connected, otherwise False.
Return type:	bool

read_remote_register(address, offset)[source]¶

Read data from a slave. Note that this waits 5ms for slave data to be aquired before making the final read.

Parameters:	address – Address of slave to read. Can be 0x50 to 0x5F for slave 1 to 16. offset – Address of data to read. Can be 0x00 to 0x7F
Returns:	Register Value
Return type:	integer

ready()[source]¶

Returns if the driver is ready

Returns:	Ready status
Return type:	boolean

reset()[source]¶: This is a hack in the Arduino lib - the placeholder is for compatablity

reset_diagnostic_counts()[source]¶

Reset the master’s diagnostic counters

Returns:	No return value

reset_remote_diagnostic_counts(address)[source]¶

Reset a slave’s diagnostic counters

Parameters:	address – Address of slave to read. Can be 0x50 to 0x5F for slave 1 to 16.
Returns:	No return value

set_drive(motorNum, direction, level)[source]¶

Drive a motor at a level

Parameters:	motoNum – Motor number from 0 to 33 direction – 0 or 1 for forward and backward level – (-255) to 255 for drive strength
Returns:	No return value

write_remote_register(address, offset, dataToWrite)[source]¶

Write data from a slave

Parameters:	address – Address of slave to read. Can be 0x50 to 0x5F for slave 1 to 16. offset – Address of data to read. Can be 0x00 to 0x7F dataToWrite – The data to write
Returns:	No return value

class qwiic_scmd.SCMDDiagnostics[source]¶

Object used for diagnostic reporting.

Variables:	numberOfSlaves – U_I2C_RD_ERR – U_I2C_WR_ERR – U_BUF_DUMPED – E_I2C_RD_ERR – E_I2C_WR_ERR – LOOP_TIME – SLV_POLL_CNT – MST_E_ERR – MST_E_STATUS – FSAFE_FAULTS – REG_OOR_CNT – REG_RO_WRITE_CNT –

Example 1: Single Motor Test¶

examples/ex1_qwiic_scmd.py¶

#!/usr/bin/env python
#-----------------------------------------------------------------------------
# A simple test to speed up and slow down 1 motor.
#------------------------------------------------------------------------
#
# Written by Mark Lindemer
# SparkFun Electronics, April 2020
# 
# This python library supports the SparkFun Electroncis qwiic 
# qwiic sensor/board ecosystem on a Raspberry Pi (and compatable) single
# board computers. 
#
# More information on qwiic is at https://www.sparkfun.com/qwiic
#
# Do you like this library? Help support SparkFun. Buy a board!
#
#==================================================================================
# Copyright (c) 2019 SparkFun Electronics
#
# Permission is hereby granted, free of charge, to any person obtaining a copy 
# of this software and associated documentation files (the "Software"), to deal 
# in the Software without restriction, including without limitation the rights 
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 
# copies of the Software, and to permit persons to whom the Software is 
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all 
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 
# SOFTWARE.
#==================================================================================
# Example 1
#

from __future__ import print_function
import time
import sys
import math
import qwiic_scmd

myMotor = qwiic_scmd.QwiicScmd()

def runExample():
	print("Motor Test.")
	R_MTR = 0
	L_MTR = 1
	FWD = 0
	BWD = 1

	if myMotor.connected == False:
		print("Motor Driver not connected. Check connections.", \
			file=sys.stderr)
		return
	myMotor.begin()
	print("Motor initialized.")
	time.sleep(.250)
	
	# Zero Motor Speeds
	myMotor.set_drive(0,0,0)
	myMotor.set_drive(1,0,0)
	
	myMotor.enable()
	print("Motor enabled")
	time.sleep(.250)


	while True:
		speed = 20
		for speed in range(20,255):
			print(speed)
			myMotor.set_drive(R_MTR,FWD,speed)
			time.sleep(.05)
		for speed in range(254,20, -1):
			print(speed)
			myMotor.set_drive(R_MTR,FWD,speed)
			time.sleep(.05)

if __name__ == '__main__':
	try:
		runExample()
	except (KeyboardInterrupt, SystemExit) as exErr:
		print("Ending example.")
		myMotor.disable()
		sys.exit(0)

Example 2: Dual Motor Test¶

examples/ex2_qwiic_scmd.py¶

#!/usr/bin/env python
#-----------------------------------------------------------------------------
# A simple test to speed up and slow down both motors in opposite directions.
#------------------------------------------------------------------------
#
# Written by Mark Lindemer
# SparkFun Electronics, April 2020
# 
# This python library supports the SparkFun Electroncis qwiic 
# qwiic sensor/board ecosystem on a Raspberry Pi (and compatable) single
# board computers. 
#
# More information on qwiic is at https://www.sparkfun.com/qwiic
#
# Do you like this library? Help support SparkFun. Buy a board!
#
#==================================================================================
# Copyright (c) 2019 SparkFun Electronics
#
# Permission is hereby granted, free of charge, to any person obtaining a copy 
# of this software and associated documentation files (the "Software"), to deal 
# in the Software without restriction, including without limitation the rights 
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 
# copies of the Software, and to permit persons to whom the Software is 
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all 
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 
# SOFTWARE.
#==================================================================================
# Example 1
#

from __future__ import print_function
import time
import sys
import math
import qwiic_scmd

myMotor = qwiic_scmd.QwiicScmd()

def runExample():
	print("Motor Test.")
	R_MTR = 0
	L_MTR = 1
	FWD = 0
	BWD = 1

	if myMotor.connected == False:
		print("Motor Driver not connected. Check connections.", \
			file=sys.stderr)
		return
	myMotor.begin()
	print("Motor initialized.")
	time.sleep(.250)
	
	# Zero Motor Speeds
	myMotor.set_drive(0,0,0)
	myMotor.set_drive(1,0,0)
	
	myMotor.enable()
	print("Motor enabled")
	time.sleep(.250)


	while True:
		speed = 20
		for speed in range(20,255):
			print(speed)
			myMotor.set_drive(R_MTR,FWD,speed)
			myMotor.set_drive(L_MTR,BWD,speed)
			time.sleep(.05)
		for speed in range(254,20, -1):
			print(speed)
			myMotor.set_drive(R_MTR,FWD,speed)
			myMotor.set_drive(L_MTR,BWD,speed)
			time.sleep(.05)

if __name__ == '__main__':
	try:
		runExample()
	except (KeyboardInterrupt, SystemExit) as exErr:
		print("Ending example.")
		myMotor.disable()
		sys.exit(0)