Open-source I2C expansion board library for PiMotics. The target for this project is to make a plugin that extended GPIO pins are treated as general GPIO pins.
- Perform a system update/upgrade
sudo apt-get update && sudo apt-get upgrade
- Install the I2C packages (installs i2c-tools & 12c-tools)
sudo apt-get install python-smbus
- Configure your Raspberry Pi to support SPI
sudo raspi-config ==> select 'advance options' ==> Enable SPI and Enable it as default boot option
- Configure your Raspberry Pi to support I2C
sudo raspi-config ==> select 'advance options' ==> Enable I2C and Enable it as default boot option
- Finish the change
Finish ==> reboot
- Add the required users to the IC2 eco system
sudo adduser pi i2c
sudo adduser root i2c
sudo adduser pim i2c
- Detecting the I2C onboard raspberry pi module: (
i2c-1= 1)
root@raspberrypi:~# sudo i2cdetect -l
i2c-1 i2c 3f804000.i2c I2C adapter
-
Detecting your expansion board
- When the board is NOT detected OR connected
root@raspberrypi:~# sudo i2cdetect -y 1 0 1 2 3 4 5 6 7 8 9 a b c d e f 00: -- -- -- -- -- -- -- -- -- -- -- -- -- 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 70: -- -- -- -- -- -- -- --- When the board IS detected AND connected
root@raspberrypi:~# sudo i2cdetect -y 1 0 1 2 3 4 5 6 7 8 9 a b c d e f 00: -- -- -- -- -- -- -- -- -- -- -- -- -- 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20: 20 21 -- -- -- -- -- -- -- -- -- -- -- -- -- -- 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 70: -- -- -- -- -- -- -- --This shows that two I2C addresses are in use – 0x20 and 1x21.
- Detecting a button press
In [1]: import sys
In [2]: sys.path.append('/opt/pimotics/pimotics/extensions/plugins/ABElectronics_Python_Libraries/library')
In [3]: from GPIOExpander import GPIOExpander
# Button IS NOT pressed
In [4]: GPIOExpander().read(7, 0x20, "input")
Out[4]: 0
# Button IS pressed
In [5]: GPIOExpander().read(7, 0x20, "input")
Out[5]: 1
- Toggling a component
In [7]: GPIOExpander().toggle(2, 0x20)
Out[7]: 1
In [8]: GPIOExpander().toggle(2, 0x20)
Out[8]: 0
- Reading a component it's current status
In [9]: GPIOExpander().read(2, 0x20)
Out[9]: 0
# Toggling a component for test purposes
In [10]: GPIOExpander().toggle(2, 0x20)
Out[10]: 1
In [11]: GPIOExpander().read(2, 0x20)
Out[11]: 1