Juniper

module Blink
open(Io)

let boardLed : uint16 = 13

let mut tState = Time:state
let mut ledState = low()

fun loop() = {
    let timerSig = Time:every(1000, inout tState)
    let ledSig =
        Signal:foldP(
            (currentTime, lastState) =>
                Io:toggle(lastState),
            inout ledState, timerSig)
    Io:digOut(boardLed, ledSig)
}

fun setup() =
    Io:setPinMode(boardLed, Io:output())