PiGPIO

Pharo interface to PiGPIO library for Raspberry Pi

PiGPIO (http://abyz.me.uk/rpi/pigpio/index.html) is used to control the GPIO pins on a Raspberry Pi. This Pharo interface uses the socket interface to the pigpiod daemon. This has four advantages:

• as the daemon runs as su, no privilege is needed for the Pharo code.
• it allows PWM and servo on all pins.
• the Pharo image can be run on the Pi using the local daemon or remote over TCP/IP.
• (last but not least) it is simple to implement

To use it, you must first start the daemon on the Pi: $ sudo pigpiod

An instance of the driver is created with: myPiController := PiGPIO onIP: '192.168.1.55' port: 8888

The IP address is an example; use 127.0.0.1 when running on the Rapberry Pi itself. . The default port number is 8888. Now you can do things like:

myPiController version.
myPiController pin: 5 value: 1.
x := myPiController digitalRead: 2.
myPiController pin: 14 pwmWrite: 128. "range default 0 - 255"
myPiController pin: 15 servoPulseWidth: 1500. "in microseconds"

I2C communication:

i2cConnectionn := myPiController openI2C: 16r68. "the I2C address of the device e.g. the DS1307 real time clock"
month := i2cConnection read8BitsAt: 5. "register 5, in this example the month in BCD format"

Announcements

Callbacks have been implemented using pharo's announcement framework. This feature is not enabled by default. It must be started with:

myPiController startEventLoop

To get notified of level changes:

myPiController pinsToWatch: #(12 13). "list of gpio's to monitor"
on: PiGPIOPinChange do: [ :event | .... ].

PiGPIOPinChange has accessors #pinNr, #newLevel, #tick. The latter represents the internal clock of the pigpiod daemon, with an accuracy of some microseconds.

Miscellaneous

Load with:

Metacello new 
	baseline: 'PiGPIO';
	repository: 'github://robvanlopik/PiGPIO';
	load .