WiringPi in Julia

Raspberry Pi 5 support for GPIO, SPI, I2C (will also work on older models)

NOTE: You must run Julia as root (or fiddle with permissions), to allow direct memory acces to GPIO.

NOTE: More documentation can be found at https://github.com/WiringPi/WiringPi/

NOTE: Will only run on a Raspberry Pi (tested on a Raspberry Pi 5). Remember to enable SPI and I2C using "sudo raspi-config".

Install Julia by running: curl -fsSL https://install.julialang.org | sh

Run julia by typing: sudo $HOME/.juliaup/bin/julia

It's even possible to generate code via Gemini (Google AI Studio). Example prompt: "Generate julia code: Draw image on SSH1106 connected to a Raspberry Pi 5 using WiringPi.jl"

Examples:

using WiringPi

# You can cut & paste simple examples in C and run it
wiringPiSetupGpio();
pinMode(17, INPUT);
pullUpDnControl(17, PUD_DOWN);

value = digitalRead(17)

Data acquisition

# Connect an ADS1115 to the I2C bus (several more chips are supported)
using WiringPi

#Pin base is where the virtual pins should start (4 of them for an ADS1115). This is almost like a variable name
pinBase=100
i2cAddress=0x48 # Default for ADS1115
ads1115Setup(pinBase, i2cAddress)

#Sets gain to ADS gain 6
digitalWrite(100, ADS1115_GAIN_6)

#Sets data rate
digitalWrite(101, ADS1115_DR_64)


value1 = analogRead(100)
value2 = analogRead(101)
value3 = analogRead(102)
value4 = analogRead(103)

voltages=[6.144,4.096,2.048,1.024,0.512,0.256]

# ADS1115_GAIN_6 = 6.144 volt
volt1=(value1/32767)*voltages[ADS1115_GAIN_6+ 1 ]

Working with interrupts:

using WiringPi

wiringPiSetupGpio();
pinMode(17, INPUT);
pullUpDnControl(17, PUD_UP);


function myInterrupt()::Cvoid
       println("Triggered")
end

 const myInterruptC = @cfunction(myInterrupt, Cvoid, ())

wiringPiISR(17, INT_EDGE_FALLING, myInterruptC)

SPI

using WiringPi
using Random

wiringPiSPISetup(0, 1000000)


myData = Vector{Cuchar}(undef, 4096)
size = 4096

# Populate the data with some random info. Normally you would not overwrite the vector above.
myData = rand(UInt8, 4096)

# A copy
sentData = deepcopy(myData)

wiringPiSPIDataRW(0, myData, size)

# If you connect MOSI to MISO, the buffer will have the same data as sent. Otherwise it will be zeroes

sentData == myData

Full example where WiringPi is driving an e-paper display, and draws a diagram using Makie. Can also be used for displaying SVG.

WiringPi.jl drive an e-paper display