Orange Pi Zero TTP224

buttons.go

package main

import (
	"fmt"
	"github.com/davecheney/gpio"
	"os"
	"os/signal"
	"time"
)

type Buttons struct {
	pins []gpio.Pin
}

func NewButtons(numbers ...int) (*Buttons, error) {
	buttons := &Buttons{
		pins: make([]gpio.Pin, len(numbers)),
	}
	for no, number := range numbers {
		pin, err := gpio.OpenPin(number, gpio.ModeInput)
		if err != nil {
			return nil, err
		}
		buttons.pins[no] = pin
	}
	return buttons, nil
}

func (b *Buttons) Watch(callback func(no int, pressed bool)) error {
	for n, p := range b.pins {
		no := n
		pin := p
		if err := pin.BeginWatch(gpio.EdgeBoth, func() {
			callback(no, pin.Get())
		}); err != nil {
			return err
		}
	}
	return nil
}

func (b *Buttons) Close() error {
	for _, pin := range b.pins {
		if err := pin.EndWatch(); err != nil {
			return err
		}
		if err := pin.Close(); err != nil {
			return err
		}
	}
	return nil
}

//                 3.3V+  [1] (2)  5V+   ==> TTP224 VCC
//      IIC SDA / GPIO12  (3) (4)  5V+
//      IIC SCL / GPIO11  (5) (6)  GND   ==> TTP224 GND
//                 GPIO6  (7) (8)  GPIO198 / UART2 TX
//                   GND  (9) (10) GPIO199 / UART2 RX
// TTP224 OUT2 <== GPIO1 (11) (12) GPIO7 ==> TTP224 OUT1
// TTP224 OUT3 <== GPIO0 (13) (14) GND
// TTP224 OUT4 <== GPIO3 (15) (16) GPIO19
//                 3.3V+ (17) (18) GPIO18
//                GPIO15 (19) (20) GND
//                GPIO16 (21) (22) GPIO2
//                GPIO14 (23) (24) GPIO13
//                   GND (25) (26) GPIO10
func main() {
	buttons, err := NewButtons(gpio.GPIO7, gpio.GPIO1, gpio.GPIO0, gpio.GPIO3)
	if err != nil {
		fmt.Printf("Error init buttons: %s\n", err)
		return
	}

	// clean up on exit
	c := make(chan os.Signal, 1)
	signal.Notify(c, os.Interrupt)
	go func() {
		for _ = range c {
			fmt.Println("Closing buttons and terminating program.")
			buttons.Close()
			os.Exit(0)
		}
	}()

	err = buttons.Watch(func(no int, pressed bool) {
		fmt.Printf("Button #%d: ", no)
		if pressed {
			fmt.Println("pressed.")
		} else {
			fmt.Println("released.")
		}
	})
	if err != nil {
		fmt.Printf("Unable to watch buttons: %s\n", err.Error())
		os.Exit(1)
	}
	fmt.Printf("Now watching buttons:\n")

	for {
		time.Sleep(2000 * time.Millisecond)
	}
}