#-----------------------------------------------------------------------------
# qwiic_dual_encoder_reader.py
#
# Python library for the dual encoder reader that is part of the SparkFun Auto pHAT.
#
# https://www.sparkfun.com/products/15083
#
#------------------------------------------------------------------------
#
# Written by SparkFun Electronics, March 2020
#
# This python library supports the SparkFun Electroncis qwiic
# qwiic sensor/board ecosystem
#
# 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.
#==================================================================================
#
# This is mostly a port of existing Arduino functionaly, so pylint is sad.
# The goal is to keep the public interface pthonic, but internal is internal
#
# pylint: disable=line-too-long, too-many-public-methods, invalid-name
#
"""
qwiic_dual_encoder_reader
===============
Python module for the[SparkFun Auto pHAT for Raspberry Pi](https://www.sparkfun.com/products/16328)
This python package enables the user to take count readings from the on-board ATTINY84 that handles reading the dual motor encoders.
The firmware that is used on the ATTiny84 is located in a separate repository here: [SparkFun Dual Encoder Reader Firmware Repository](https://github.com/sparkfun/Qwiic_Dual_Encoder_Reader)
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).
"""
#-----------------------------------------------------------------------------
from __future__ import print_function
import struct
import qwiic_i2c
# Define the device name and I2C addresses. These are set in the class defintion
# as class variables, making them avilable without having to create a class instance.
# This allows higher level logic to rapidly create a index of qwiic devices at
# runtine
#
# The name of this device
_DEFAULT_NAME = "SparkFun Qwiic Dual Encoder Reader"
# Some devices have multiple availabel addresses - this is a list of these addresses.
# NOTE: The first address in this list is considered the default I2C address for the
# device.
_AVAILABLE_I2C_ADDRESS = [0x73, 0x74] # open ADR jumper (default) = 0x73, closed ADR jumper = 0x74
# Register codes for the SparkFun Dual Encoder Reader
QDER_ID = 0x00
QDER_STATUS = 0x01 #2 - button clicked, 1 - button pressed, 0 - encoder moved
QDER_VERSION = 0x02
QDER_ENABLE_INTS = 0x04 #1 - button interrupt, 0 - encoder interrupt
QDER_COUNT1 = 0x05
QDER_DIFFERENCE1 = 0x07
QDER_COUNT2 = 0x09
QDER_DIFFERENCE2 = 0x0B
QDER_LAST_ENCODER_EVENT = 0x0D #Millis since last movement of encoder
QDER_TURN_INT_TIMEOUT = 0x0F
QDER_CHANGE_ADDRESS = 0x11
QDER_LIMIT = 0x12
_statusEncoderMovedBit = 0
_enableInterruptEncoderBit = 0
# define the class that encapsulates the device being created. All information associated with this
# device is encapsulated by this class. The device class should be the only value exported
# from this module.
[docs]class QwiicDualEncoderReader(object):
"""
QwiicDualEncoderReader
:param address: The I2C address to use for the device.
If not provided, the default address is used.
:param i2c_driver: An existing i2c driver object. If not provided
a driver object is created.
:return: The QwiicDualEncoderReader device object.
:rtype: Object
"""
# Constructor
device_name = _DEFAULT_NAME
available_addresses = _AVAILABLE_I2C_ADDRESS
# Constructor
def __init__(self, address=None, i2c_driver=None):
# Did the user specify an I2C address?
self.address = address if address is not None else self.available_addresses[0]
# load the I2C driver if one isn't provided
if i2c_driver is None:
self._i2c = qwiic_i2c.getI2CDriver()
if self._i2c is None:
print("Unable to load I2C driver for this platform.")
return
else:
self._i2c = i2c_driver
# ----------------------------------
# isConnected()
#
# Is an actual board connected to our system?
[docs] def is_connected(self):
"""
Determine if a device is conntected to the system..
:return: True if the device is connected, otherwise False.
:rtype: bool
"""
return qwiic_i2c.isDeviceConnected(self.address)
connected = property(is_connected)
# ----------------------------------
# begin()
#
# Initialize the system/validate the board.
[docs] def begin(self):
"""
Initialize the operation of the Dual Encoder Reader module
:return: Returns true of the initializtion was successful, otherwise False.
:rtype: bool
"""
# Basically return True if we are connected...
return self.is_connected()
#----------------------------------------------------------------
# clear_interrupts()
#
# Clears the moved bit
[docs] def clear_interrupts(self):
"""
Clears the moved bit
:return: No return Value
"""
self._i2c.writeByte(self.address, QDER_STATUS, 0)
#----------------------------------------------------------------
# get_count1()
#
# Returns the number of "ticks" the encoder1 has turned
[docs] def get_count1(self):
"""
Returns the number of "ticks" the encoder1 has turned
:return: number of encoder pulses
:rtype: word as integer
"""
c1 = self._i2c.readWord(self.address, QDER_COUNT1)
# encoder reader returns a SIGNED 16 bit int
# python receives this as simply 16 bits of data
# we need to accept negative values
if c1 > 32767:
c1 -= 65536
return c1
#----------------------------------------------------------------
# get_count2()
#
# Returns the number of "ticks" the encoder2 has turned
[docs] def get_count2(self):
"""
Returns the number of "ticks" the encoder2 has turned
:return: number of encoder pulses
:rtype: word as integer
"""
c2 = self._i2c.readWord(self.address, QDER_COUNT2)
# encoder reader returns a SIGNED 16 bit int
# python receives this as simply 16 bits of data
# we need to accept negative values
if c2 > 32767:
c2 -= 65536
return c2
#----------------------------------------------------------------
# set_count1()
#
# Set the encoder count1 to a specific amount
[docs] def set_count1(self, amount):
"""
Set the encoder count1 to a specific amount
:param amount: the value to set the counter to
:return: no return value
"""
return self._i2c.writeWord(self.address, QDER_COUNT1, amount)
#----------------------------------------------------------------
# set_count2()
#
# Set the encoder count2 to a specific amount
[docs] def set_count2(self, amount):
"""
Set the encoder count2 to a specific amount
:param amount: the value to set the counter to
:return: no return value
"""
return self._i2c.writeWord(self.address, QDER_COUNT2, amount)
count1 = property(get_count1, set_count1)
count2 = property(get_count2, set_count2)
#----------------------------------------------------------------
# get_limit()
#
# Returns the limit of allowed counts before wrapping. 0 is disabled
[docs] def get_limit(self):
"""
Returns the limit of allowed counts before wrapping. 0 is disabled
:return: The limit
:rtype: integer
"""
return self._i2c.readWord(self.address, QDER_LIMIT)
#----------------------------------------------------------------
# set_limit()
#
# Set the encoder count limit to a specific amount
[docs] def set_limit(self, amount):
"""
Set the encoder count limit to a specific amount
:param amount: the value to set the limit to
:return: no return value
"""
return self._i2c.writeWord(self.address, QDER_LIMIT, amount)
limit = property(get_limit, set_limit)
#----------------------------------------------------------------
# get_diff()
#
# Returns the number of ticks since last check
[docs] def get_diff(self, clear_value=False):
"""
Returns the number of ticks since last check
:param clearValue: Set to True to clear the current value. Default is False
:return: the difference
:rtype: integer
"""
difference = self._i2c.readWord(self.address, QDER_DIFFERENCE1)
if clear_value:
self._i2c.writeWord(self.address, QDER_DIFFERENCE1, 0)
return difference
#----------------------------------------------------------------
# has_moved()
#
# Returns true if encoder has moved
[docs] def has_moved(self):
"""
Returns true if encoder has moved
:return: Moved state
:rtype: Boolean
"""
status = self._i2c.readByte(self.address, QDER_STATUS)
self._i2c.writeByte(self.address, QDER_STATUS, \
status & ~(1 << _statusEncoderMovedBit))
return (status & (1 << _statusEncoderMovedBit)) != 0
moved = property(has_moved)
#----------------------------------------------------------------
# since_last_movement()
#
# Returns the number of milliseconds since the last encoder movement
# By default, clear the current value
[docs] def since_last_movement(self, clear_value=True):
"""
Returns the number of milliseconds since the last encoder movement
By default, clear the current value
:param clearValue: Clear out the value? True by default
:return: time since last encoder movement
:rtype: integer
"""
time_elapsed = self._i2c.readWord(self.address, QDER_LAST_ENCODER_EVENT)
# Clear the current value if requested
if clear_value:
self._i2c.writeWord(QDER_LAST_ENCODER_EVENT, 0)
return time_elapsed
#----------------------------------------------------------------
# get_version()
#
# Returns a int of the firmware version number
[docs] def get_version(self):
"""
Returns a integer of the firmware version number
:return: The firmware version
:rtype: integer
"""
return self._i2c.readWord(self.address, QDER_VERSION)
version = property(get_version)
#----------------------------------------------------------------
# set_int_timeout()
#
# Set number of milliseconds that elapse between end of encoder turning and interrupt firing
[docs] def set_int_timeout(self, timeout):
"""
Set number of milliseconds that elapse between end of encoder turning and interrupt firing
:param timeout: the timeout value in milliseconds
:return: No return value
"""
self._i2c.writeWord(self.address, QDER_TURN_INT_TIMEOUT, timeout)
#----------------------------------------------------------------
# get_int_timeout()
#
# Get number of milliseconds that elapse between end of encoder turning and interrupt firing
[docs] def get_int_timeout(self):
"""
Get number of milliseconds that elapse between end of encoder turning and interrupt firing
:return: the timeout value
:rtype: integer
"""
return self._i2c.readWord(self.address, QDER_TURN_INT_TIMEOUT)
int_timeout = property(get_int_timeout, set_int_timeout)