gpio

The gpio module drives hardware on single-board computers such as the Raspberry Pi: digital pins (with internal pull-up/down and blocking edge waits), hardware PWM, and the I²C and SPI buses. Pins and buses are referenced by an integer handle. Import it with import gpio.

Digital pins

Function	Signature	Description
`init`	`gpio.init() → bool`	Initialize the GPIO subsystem
`open`	`gpio.open(name: string) → int`	Open a pin by name (e.g. `"GPIO18"`); `-1` if unknown
`name`	`gpio.name(h: int) → string`	The pin’s name (`""` if unknown)
`output`	`gpio.output(h: int, initLevel?: int) → bool`	Set as output; optional initial level `0`/`1` (defaults low)
`input`	`gpio.input(h: int, pull?: string) → bool`	Set as input; `pull` is `"up"`, `"down"`, or `"float"`
`read`	`gpio.read(h: int) → int`	Read the level (`0` or `1`)
`write`	`gpio.write(h: int, level: int) → bool`	Drive the level (`0` or `1`)
`waitEdge`	`gpio.waitEdge(h: int, edge: string, timeoutMs: int) → bool`	Block for an edge (`"rising"`, `"falling"`, `"both"`); `false` on timeout
`close`	`gpio.close(h: int) → bool`	Release the pin

gpio.pwm

Hardware PWM on the BCM2835 channels (GPIO12/13/18/19 on the Pi).

Function	Signature	Description
`set`	`gpio.pwm.set(h: int, dutyPct, freqHz) → bool`	Start PWM at a duty cycle (percent) and frequency
`stop`	`gpio.pwm.stop(h: int) → bool`	Stop PWM on the pin

gpio.i2c

Function	Signature	Description
`open`	`gpio.i2c.open(busNum: int) → int`	Open an I²C bus; `-1` on error
`write`	`gpio.i2c.write(h: int, addr: int, bytes: string) → bool`	Write bytes to a device
`read`	`gpio.i2c.read(h: int, addr: int, n: int) → string`	Read `n` bytes from a device
`tx`	`gpio.i2c.tx(h: int, addr: int, tx: string, nRead: int) → string`	Combined write-then-read with a repeated start (register-pointer sensors)
`close`	`gpio.i2c.close(h: int) → bool`	Close the bus

gpio.spi

Function	Signature	Description
`open`	`gpio.spi.open(bus: int, cs: int, speedHz: int, mode: int) → int`	Open an SPI device; `-1` on error
`transfer`	`gpio.spi.transfer(h: int, txBytes: string) → string`	Full-duplex transfer; returns the received bytes
`close`	`gpio.spi.close(h: int) → bool`	Close the device

Example

import gpio
import time

gpio.init()

// blink an LED on GPIO18
let led = gpio.open("GPIO18")
gpio.output(led)

let i = 0
while i < 10 {
    gpio.write(led, 1)
    time.timer.sleep(250)
    gpio.write(led, 0)
    time.timer.sleep(250)
    i += 1
}

// read a button on GPIO23 with an internal pull-up, wait for a press
let btn = gpio.open("GPIO23")
gpio.input(btn, "up")
if gpio.waitEdge(btn, "falling", 5000) {
    println("pressed")
}

gpio.close(led)
gpio.close(btn)

Standard library · View as Markdown · llms-full.txt