func main() {
// get a pin by name. You could also just use the logical pin number, but this is
// more readable. On BeagleBone, USR0 is an on-board LED.
ledPin, err := hwio.GetPin("USR1")
// Generally we wouldn't expect an error, but perhaps someone is running this a
if err != nil {
fmt.Println(err)
os.Exit(1)
}
// Set the mode of the pin to output. This will return an error if, for example,
// we were trying to set an analog input to an output.
err = hwio.PinMode(ledPin, hwio.OUTPUT)
if err != nil {
fmt.Println(err)
os.Exit(1)
}
// Run the blink forever
for {
hwio.DigitalWrite(ledPin, hwio.HIGH)
hwio.Delay(1000)
hwio.DigitalWrite(ledPin, hwio.LOW)
hwio.Delay(1000)
}
}
func main() {
// Get the pins we're going to use. These are on a beaglebone.
dataPin, _ := hwio.GetPin("P8.3") // connected to pin 14
clockPin, _ := hwio.GetPin("P8.4") // connected to pin 11
storePin, _ := hwio.GetPin("P8.5") // connected to pin 12
// Make them all outputs
hwio.PinMode(dataPin, hwio.OUTPUT)
hwio.PinMode(clockPin, hwio.OUTPUT)
hwio.PinMode(storePin, hwio.OUTPUT)
data := 0
// Set the initial state of the clock and store pins to low. These both
// trigger on the rising edge.
hwio.DigitalWrite(clockPin, hwio.LOW)
hwio.DigitalWrite(storePin, hwio.LOW)
for {
// Shift out 8 bits
hwio.ShiftOut(dataPin, clockPin, uint(data), hwio.MSBFIRST)
// You can use this line instead to clock out 16 bits if you have
// two 74HC595's chained together
// hwio.ShiftOutSize(dataPin, clockPin, uint(data), hwio.MSBFIRST, 16)
// Pulse the store pin once
hwio.DigitalWrite(storePin, hwio.HIGH)
hwio.DigitalWrite(storePin, hwio.LOW)
// Poor humans cannot read binary as fast as the machine can display it
hwio.Delay(100)
data++
}
}