CHIP_IO

A CHIP GPIO library

Debian File Installation:

There are now pre-compiled binary deb files for the CHIP that do not require any build tools on a CHIP/CHIP Pro.

Go to this page: https://github.com/xtacocorex/CHIP_IO/releases/latest Or Go to this page: https://xtacocorex.github.io/chip_io_releases/index.html

Download the .deb file for the version of Python you are running. Then install with dpkg, like the following example:

sudo dpkg -i python-chip-io_0.5.9-1_armhf.deb

Manual Installation::

For Python2.7::

sudo apt-get update
sudo apt-get install git build-essential python-dev python-pip flex bison chip-dt-overlays -y
git clone git://github.com/xtacocorex/CHIP_IO.git
cd CHIP_IO
sudo python setup.py install
cd ..

For Python3::

sudo apt-get update
sudo apt-get install git build-essential python3-dev python3-pip flex bison chip-dt-overlays -y
git clone git://github.com/xtacocorex/CHIP_IO.git
cd CHIP_IO
sudo python3 setup.py install
cd ..

PyPi Installation::

For Python2.7::

sudo apt-get update
sudo apt-get install git build-essential python-dev python-pip flex bison chip-dt-overlays -y
sudo pip install CHIP-IO

For Python3::

sudo apt-get update
sudo apt-get install git build-essential python3-dev python3-pip flex bison chip-dt-overlays -y
sudo pip3 install CHIP-IO

Usage

Using the library is very similar to the excellent RPi.GPIO library used on the Raspberry Pi. Below are some examples.

All scripts that require GPIO, PWM (HW and/or SW), and Overlay Manager need to be run with super user permissions!

Allowable Pin Names for the Library

The following "table" is the allowable pin names that are able to be used by the library. The Name column is the normal name used on the CHIP Headers, the Alt Name column is the value used by the PocketCHIP header (if it's broken out), and the Key is the Header and Pin Number the the Pin is physically located. Either of these 3 means is able to specify a pin in CHIP_IO.

+------------------+--------------------------+----------------+-----------------+-----------------+ | CHIP (Main Name) | PocketCHIP/CHIP Pro Name | Key (Alt Name) | HW Support | Edge Detect | +------------------+--------------------------+----------------+-----------------+-----------------+ | TWI1-SDA | KPD-I2C-SDA | U13_9 | CHIP/CHIP PRO | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | TWI1-SCK | KPD-I2C-SCL | U13_11 | CHIP/CHIP PRO | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | LCD-D2 | UART2-TX | U13_17 | CHIP/CHIP PRO | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | PWM0 | PWM0 | U13_18 | CHIP/CHIP PRO | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | PWM1 | PWM1 | EINT13 | CHIP PRO | YES | +------------------+--------------------------+----------------+-----------------+-----------------+ | LCD-D4 | UART2-CTS | U13_19 | CHIP/CHIP PRO | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | LCD-D3 | UART2-RX | U13_20 | CHIP/CHIP PRO | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | LCD-D6 | LCD-D6 | U13_21 | CHIP | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | LCD-D5 | UART2-RTS | U13_22 | CHIP/CHIP PRO | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | LCD-D10 | LCD-D10 | U13_23 | CHIP | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | LCD-D7 | LCD-D7 | U13_24 | CHIP | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | LCD-D12 | LCD-D12 | U13_25 | CHIP | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | LCD-D11 | LCD-D11 | U13_26 | CHIP | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | LCD-D14 | LCD-D14 | U13_27 | CHIP | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | LCD-D13 | LCD-D13 | U13_28 | CHIP | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | LCD-D18 | LCD-D18 | U13_29 | CHIP | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | LCD-D15 | LCD-D15 | U13_30 | CHIP | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | LCD-D20 | LCD-D20 | U13_31 | CHIP | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | LCD-D19 | LCD-D19 | U13_32 | CHIP | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | LCD-D22 | LCD-D22 | U13_33 | CHIP | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | LCD-D21 | LCD-D21 | U13_34 | CHIP | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | LCD-CLK | LCD-CLK | U13_35 | CHIP | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | LCD-D23 | LCD-D23 | U13_36 | CHIP | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | LCD-VSYNC | LCD-VSYNC | U13_37 | CHIP | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | LCD-HSYNC | LCD-HSYNC | U13_38 | CHIP | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | LCD-DE | LCD-DE | U13_40 | CHIP | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | UART1-TX | UART-TX | U14_3 | CHIP/CHIP PRO | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | UART1-RX | UART-RX | U14_5 | CHIP/CHIP PRO | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | LRADC | ADC | U14_11 | CHIP/CHIP PRO | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | XIO-P0 | XIO-P0 | U14_13 | CHIP | YES | +------------------+--------------------------+----------------+-----------------+-----------------+ | XIO-P1 | XIO-P1 | U14_14 | CHIP | YES | +------------------+--------------------------+----------------+-----------------+-----------------+ | XIO-P2 | GPIO1 | U14_15 | CHIP | YES | +------------------+--------------------------+----------------+-----------------+-----------------+ | XIO-P3 | GPIO2 | U14_16 | CHIP | YES | +------------------+--------------------------+----------------+-----------------+-----------------+ | XIO-P4 | GPIO3 | U14_17 | CHIP | YES | +------------------+--------------------------+----------------+-----------------+-----------------+ | XIO-P5 | GPIO4 | U14_18 | CHIP | YES | +------------------+--------------------------+----------------+-----------------+-----------------+ | XIO-P6 | GPIO5 | U14_19 | CHIP | YES | +------------------+--------------------------+----------------+-----------------+-----------------+ | XIO-P7 | GPIO6 | U14_20 | CHIP | YES | +------------------+--------------------------+----------------+-----------------+-----------------+ | AP-EINT1 | KPD-INT | U14_23 | CHIP/CHIP PRO | YES | +------------------+--------------------------+----------------+-----------------+-----------------+ | AP-EINT3 | AP-INT3 | U14_24 | CHIP/CHIP PRO | YES | +------------------+--------------------------+----------------+-----------------+-----------------+ | TWI2-SDA | I2C-SDA | U14_25 | CHIP/CHIP PRO | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | TWI2-SCK | I2C-SCL | U14_26 | CHIP/CHIP PRO | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | CSIPCK | SPI-SEL | U14_27 | CHIP/CHIP PRO | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | CSICK | SPI-CLK | U14_28 | CHIP/CHIP PRO | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | CSIHSYNC | SPI-MOSI | U14_29 | CHIP/CHIP PRO | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | CSIVSYNC | SPI-MISO | U14_30 | CHIP/CHIP PRO | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | CSID0 | D0 | U14_31 | CHIP/CHIP PRO | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | CSID1 | D1 | U14_32 | CHIP/CHIP PRO | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | CSID2 | D2 | U14_33 | CHIP/CHIP PRO | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | CSID3 | D3 | U14_34 | CHIP/CHIP PRO | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | CSID4 | D4 | U14_35 | CHIP/CHIP PRO | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | CSID5 | D5 | U14_36 | CHIP/CHIP PRO | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | CSID6 | D6 | U14_37 | CHIP/CHIP PRO | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | CSID7 | D7 | U14_38 | CHIP/CHIP PRO | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | I2S-MCLK | EINT19 | 21 | CHIP PRO | YES | +------------------+--------------------------+----------------+-----------------+-----------------+ | I2S-BCLK | I2S-BCLK | 22 | CHIP PRO | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | I2S-LCLK | I2S-LCLK | 23 | CHIP PRO | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | I2S-DO | EINT19 | 24 | CHIP PRO | NO | +------------------+--------------------------+----------------+-----------------+-----------------+ | I2S-DI | EINT24 | 25 | CHIP PRO | YES | +------------------+--------------------------+----------------+-----------------+-----------------+

GPIO Setup

Import the library, and setup as GPIO.OUT or GPIO.IN::

import CHIP_IO.GPIO as GPIO
GPIO.setup("CSID0", GPIO.OUT)

You can also refer to the pin number::

GPIO.setup("U14_31", GPIO.OUT)

You can also refer to the bin based upon its alternate name::

GPIO.setup("GPIO1", GPIO.IN)

GPIO Miscellaneous

Debug can be enabled/disabled by the following command::

# Enable Debug
GPIO.toggle_debug()

You can determine if the hardware is a CHIP/CHIP Pro using the following::

# Determine hardware
# 0 For CHIP
# 1 For CHIP Pro
GPIO.is_chip_pro()

GPIO Output

Setup the pin for output, and write GPIO.HIGH or GPIO.LOW. Or you can use 1 or 0.::

import CHIP_IO.GPIO as GPIO
GPIO.setup("CSID0", GPIO.OUT)
GPIO.output("CSID0", GPIO.HIGH)

GPIO Input

Inputs work similarly to outputs.::

import CHIP_IO.GPIO as GPIO
GPIO.setup("CSID0", GPIO.IN)

Other options when setting up pins::

# Specify pull up/pull down settings on a pin
GPIO.setup("CSID0", GPIO.IN, pull_up_down=GPIO.PUD_UP)

# Specify initial value for an output
GPIO.setup("CSID0", GPIO.OUT, initial=1)

Pull Up/Down values are only for pins that are provided by the R8, the XIO are not capable of this. The allowable values are: PUD_OFF, PUD_UP, and PUD_DOWN.

Polling inputs::

if GPIO.input("CSID0"):
    print("HIGH")
else:
    print("LOW")

Read lots of data::

# Get 8 bits of data in one shot
mybyte = GPIO.read_byte("LCD-D3")

# Get 16 bits of data in one shot
myword = GPIO.read_word("XIO-P4")

This code was initially added by brettcvz and I cleaned it up and expanded it.

You can quickly change a pins direction::

GPIO.direction("XIO-P3", GPIO.OUT)
GPIO.direction("XIO-P3", GPIO.IN)

You can also re-setup a pin in order to change direction, note that this is a slower operation::

GPIO.setup("XIO-P3", GPIO.OUT)
GPIO.setup("XIO-P3", GPIO.IN)

The edge detection code below only works for the AP-EINT1, AP-EINT3, and XPO Pins on the CHIP.

Waiting for an edge (GPIO.RISING, GPIO.FALLING, or GPIO.BOTH::

GPIO.wait_for_edge(channel, GPIO.RISING)

Detecting events::

GPIO.setup("XIO-P0", GPIO.IN)
GPIO.add_event_detect("XIO-P0", GPIO.FALLING)
#your amazing code here

#detect wherever:
if GPIO.event_detected("XIO-P0"):
    print "event detected!"

CHIP_IO can also handle adding callback functions on any pin that supports edge detection. Note that only one callback function can be specified per Pin, if you try to set more, an exception will be thrown.::

def mycallback(channel):
    print("we hit the edge we want")

GPIO.setup("GPIO3", GPIO.IN)

# Add Event Detect and Callback Separately for Falling Edge
GPIO.add_event_detect("GPIO3", GPIO.FALLING)
GPIO.add_event_callback("GPIO3", mycallback)

# Add Event Detect and Callback Separately for Rising Edge
GPIO.add_event_detect("GPIO3", GPIO.RISING)
GPIO.add_event_callback("GPIO3", mycallback)

# Add Callback for Both Edges using the add_event_detect() method
GPIO.add_event_detect("GPIO3", GPIO.BOTH, mycallback)

# Remove callback with the following
GPIO.remove_event_detect("GPIO3")

# bouncetime is also able to be set for both GPIO.add_event_detect() and GPIO.add_event_callback()
GPIO.add_event_detect("GPIO3", GPIO.FALLING, bouncetime=300)
GPIO.add_event_callback("GPIO3", GPIO.RISING, mycallback, bouncetime=300)

GPIO Cleanup

To clean up the GPIO when done, do the following::

# Clean up every exported GPIO Pin
GPIO.cleanup()

# Clean up a single pin (keeping everything else intact)
GPIO.cleanup("XIO-P0")

PWM::

Hardware PWM requires a DTB Overlay loaded on the CHIP to allow the kernel to know there is a PWM device available to use. :: import CHIP_IO.PWM as PWM

Determine hardware

# 0 For CHIP
# 1 For CHIP Pro
PWM.is_chip_pro()

# Enable/Disable Debug
PWM.toggle_debug()

#PWM.start(channel, duty, freq=2000, polarity=0)
#duty values are valid 0 (off) to 100 (on)
PWM.start("PWM0", 50)
PWM.set_duty_cycle("PWM0", 25.5)
PWM.set_frequency("PWM0", 10)

# To stop PWM
PWM.stop("PWM0")
PWM.cleanup()

#For specific polarity: this example sets polarity to 1 on start:
PWM.start("PWM0", 50, 2000, 1)

SOFTPWM::

import CHIP_IO.SOFTPWM as SPWM
# Determine hardware
# 0 For CHIP
# 1 For CHIP Pro
SPWM.is_chip_pro()

# Enable/Disable Debug
SPWM.toggle_debug()

#SPWM.start(channel, duty, freq=2000, polarity=0)
#duty values are valid 0 (off) to 100 (on)
#you can choose any pin
SPWM.start("XIO-P7", 50)
SPWM.set_duty_cycle("XIO-P7", 25.5)
SPWM.set_frequency("XIO-P7", 10)

# To Stop SPWM
SPWM.stop("XIO-P7")

# Cleanup
SPWM.cleanup()

#For specific polarity: this example sets polarity to 1 on start:
SPWM.start("XIO-P7", 50, 2000, 1)

Use SOFTPWM at low speeds (hundreds of Hz) for the best results. Do not use for anything that needs high precision or reliability.

If using SOFTPWM and PWM at the same time, import CHIP_IO.SOFTPWM as SPWM or something different than PWM as to not confuse the library.

SERVO::

import CHIP_IO.SERVO as SERVO
# Determine hardware
# 0 For CHIP
# 1 For CHIP Pro
SERVO.is_chip_pro()

# Enable/Disable Debug
SERVO.toggle_debug()

#SPWM.start(channel, angle=0, range=180)
#angle values are between +/- range/2)
#you can choose any pin except the XIO's
SERVO.start("CSID4", 50)
SERVO.set_angle("CSID4", 25.5)
SERVO.set_range("CSID4", 90)

# To Stop Servo
SERVO.stop("CSID4")

# Cleanup
SERVO.cleanup()

The Software Servo control only works on the LCD and CSI pins. The XIO is too slow to control.

LRADC::

The LRADC was enabled in the 4.4.13-ntc-mlc. This is a 6 bit ADC that is 2 Volt tolerant. Sample code below details how to talk to the LRADC.::

import CHIP_IO.LRADC as ADC
# Enable/Disable Debug
ADC.toggle_debug()

# Check to see if the LRADC Device exists
# Returns True/False
ADC.get_device_exists()

# Setup the LRADC
# Specify a sampling rate if needed
ADC.setup(rate)

# Get the Scale Factor
factor = ADC.get_scale_factor()

# Get the allowable Sampling Rates
sampleratestuple = ADC.get_allowable_sample_rates()

# Set the sampling rate
ADC.set_sample_rate(rate)

# Get the current sampling rate
currentrate = ADC.get_sample_rate()

# Get the Raw Channel 0 or 1 data
raw = ADC.get_chan0_raw()
raw = ADC.get_chan1_raw()

# Get the factored ADC Channel data
fulldata = ADC.get_chan0()
fulldata = ADC.get_chan1()

SPI::

SPI requires a DTB Overlay to access. CHIP_IO does not contain any SPI specific code as the Python spidev module works when it can see the SPI bus.

Overlay Manager::

The Overlay Manager enables you to quickly load simple Device Tree Overlays. The options for loading are: PWM0, SPI2, CUST. The Overlay Manager is smart enough to determine if you are trying to load PWM on a CHIP Pro and will fail due to the base DTB for the CHIP Pro supporting PWM0/1 out of the box.

Only one of each type of overlay can be loaded at a time, but all three options can be loaded simultaneously. So you can have SPI2 without PWM0, but you cannot have SPI2 loaded twice. :: import CHIP_IO.OverlayManager as OM

The toggle_debug() function turns on/off debug printing

OM.toggle_debug()

# To load an overlay, feed in the name to load()
OM.load("PWM0")

# To verify the overlay was properly loaded, the get_ functions return booleans
OM.get_pwm_loaded()
OM.get_spi_loaded()

# To unload an overlay, feed in the name to unload()
OM.unload("PWM0")

To use a custom overlay, you must build and compile it properly per the DIP Docs: http://docs.getchip.com/dip.html#development-by-example There is no verification that the Custom Overlay is setup properly, it's fire and forget :: import CHIP_IO.OverlayManager as OM

The full path to the dtbo file needs to be specified

OM.load("CUST","/home/chip/projects/myfunproject/overlays/mycustomoverlay.dtbo")

# You can check for loading like above, but it's really just there for sameness
OM.get_custom_loaded()

# To unload, just call unload()
OM.unload("CUST")

OverlayManager requires a 4.4 kernel with the CONFIG_OF_CONFIGFS option enabled in the kernel config.

Utilties::

CHIP_IO now supports the ability to enable and disable the 1.8V port on U13. This voltage rail isn't enabled during boot.

To use the utilities, here is sample code::

import CHIP_IO.Utilities as UT
# Enable/Disable Debug
UT.toggle_debug()

# Enable 1.8V Output
UT.enable_1v8_pin()

# Set 2.0V Output
UT.set_1v8_pin_voltage(2.0)

# Set 2.6V Output
UT.set_1v8_pin_voltage(2.6)

# Set 3.3V Output
UT.set_1v8_pin_voltage(3.3)

# Disable 1.8V Output
UT.disable_1v8_pin()

# Get currently-configured voltage (returns False if the pin is not enabled as output)
UT.get_1v8_pin_voltage()

# Unexport Everything
UT.unexport_all()

# Determine if you are running a CHIP/CHIP Pro
# This returns True if the computer is a CHIP Pro and False if it is a CHIP
UT.is_chip_pro()

Running tests

Install py.test to run the tests. You'll also need the python compiler package for py.test.::

# Python 2.7
sudo apt-get install python-pytest
# Python 3
sudo apt-get install python3-pytest

To run the tests, do the following.::

# If only one version of Python is installed
# Python 2
sudo make pytest2
# Python 3
sudo make pytest3
# If more than one version of Python, run through both
sudo make test

Credits

The CHIP IO Python library was originally forked from the Adafruit Beaglebone IO Python Library. The BeagleBone IO Python library was originally forked from the excellent MIT Licensed RPi.GPIO library written by Ben Croston.

License

CHIP IO port by Robert Wolterman, released under the MIT License. Beaglebone IO Library Written by Justin Cooper, Adafruit Industries. BeagleBone IO Python library is released under the MIT License.