BeagleBone Blink - Maps work but Arrays don't?

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Nicholas L

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Dec 27, 2018, 12:44:13 AM12/27/18

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Hello everyone, still learning golang and tried to play around with an LED on a custom cape. I am perplexed by the following issue I am facing when doing a simple blink example:

When I used maps to store the LedDrivers of each GPIO corresponding to the colour, the code worked perfectly, was able to get my LED to blink.

package main

import (
    "gobot.io/x/gobot"
    "gobot.io/x/gobot/drivers/gpio"
    "gobot.io/x/gobot/platforms/beaglebone"
)

// BBB LED Pins
const gpioRed = "P8_9"    // GPIO_69
const gpioGreen = "P8_12" // GPIO_44
const gpioBlue = "P8_11"  // GPIO_45
const gpioPower = "P9_14" // GPIO_50

func main() {
    beagleboneAdaptor := beaglebone.NewAdaptor()

    ledPower := gpio.NewLedDriver(beagleboneAdaptor, gpioPower)
    ledColors := map[string]*gpio.LedDriver{
        "red":   gpio.NewLedDriver(beagleboneAdaptor, gpioRed),
        "green": gpio.NewLedDriver(beagleboneAdaptor, gpioGreen),
        "blue":  gpio.NewLedDriver(beagleboneAdaptor, gpioBlue),
    }

    work := func() {

        // init
        ledPower.Off()
        ledColors["red"].On()
        ledColors["blue"].On()
        ledColors["green"].On()
        //
        ledColorSwitch("blue", ledColors)

        gobot.Every(1*time.Second, func() {
            ledPower.Toggle()
        })
    }

    robot := gobot.NewRobot("blinkBot",
        []gobot.Connection{beagleboneAdaptor},
        []gobot.Device{ledPower, ledColors["red"], ledColors["green"], ledColors["blue"]},
        work,
    )
    robot.Start()
}

func ledColorSwitch(color string, mLed map[string]*gpio.LedDriver) {
    switch color {
    case "red":
        mLed["red"].Off()
    case "green":
        mLed["green"].Off()
    case "blue":
        mLed["blue"].Off()
    case "cyan":
        mLed["red"].Off()
        mLed["green"].Off()
    case "magenta":
        mLed["red"].Off()
        mLed["blue"].Off()
    case "yellow":
        mLed["green"].Off()
        mLed["blue"].Off()
    case "white":
        mLed["red"].Off()
        mLed["green"].Off()
        mLed["blue"].Off()
    default:
    }
}

However when I tried to use an array, nothing seemed to work. I tried to read up on the data types but i could not get any idea where i went wrong still. Trying to understand where i went wrong or if i am not using it correctly.

package main

import (
    "gobot.io/x/gobot"
    "gobot.io/x/gobot/drivers/gpio"
    "gobot.io/x/gobot/platforms/beaglebone"
)

// BBB LED Pins
const pinRed = "P8_9"    // GPIO_69
const pinGreen = "P8_12" // GPIO_44
const pinBlue = "P8_11"  // GPIO_45
const pinPower = "P9_14" // GPIO_50

func main() {
    beagleboneAdaptor := beaglebone.NewAdaptor()

    gpioPower := gpio.NewLedDriver(beagleboneAdaptor, pinPower)
    gpioColorArray := [3]*gpio.LedDriver{
        gpio.NewLedDriver(beagleboneAdaptor, pinRed),
        gpio.NewLedDriver(beagleboneAdaptor, pinGreen),
        gpio.NewLedDriver(beagleboneAdaptor, pinBlue),
    }

    work := func() {

        // init
        gpioPower.Off()
        gpioColorArray[0].On()
        gpioColorArray[1].On()
        gpioColorArray[2].On()

        // blue LED
        gpioColorArray[2].Off()

        gobot.Every(1*time.Second, func() {
            gpioPower.Toggle()
        })
    }

    robot := gobot.NewRobot("blinkBot",
        []gobot.Connection{beagleboneAdaptor},
        []gobot.Device{gpioPower, gpioColorArray[0], gpioColorArray[1], gpioColorArray[2]},
        work,
    )
    robot.Start()
}