example_test.go

// Copyright 2018 The Periph Authors. All rights reserved.
// Use of this source code is governed under the Apache License, Version 2.0
// that can be found in the LICENSE file.

package spi_test

import (
	"fmt"
	"log"

	"periph.io/x/conn/v3/driver/driverreg"
	"periph.io/x/conn/v3/physic"
	"periph.io/x/conn/v3/spi"
	"periph.io/x/conn/v3/spi/spireg"
)

func Example() {
	// Make sure periph is initialized.
	// TODO: Use host.Init(). It is not used in this example to prevent circular
	// go package import.
	if _, err := driverreg.Init(); err != nil {
		log.Fatal(err)
	}

	// Use spireg SPI port registry to find the first available SPI bus.
	p, err := spireg.Open("")
	if err != nil {
		log.Fatal(err)
	}
	defer p.Close()

	// Convert the spi.Port into a spi.Conn so it can be used for communication.
	c, err := p.Connect(physic.MegaHertz, spi.Mode3, 8)
	if err != nil {
		log.Fatal(err)
	}

	// Write 0x10 to the device, and read a byte right after.
	write := []byte{0x10, 0x00}
	read := make([]byte, len(write))
	if err := c.Tx(write, read); err != nil {
		log.Fatal(err)
	}
	// Use read.
	fmt.Printf("%v\n", read[1:])
}

func ExamplePins() {
	// Make sure periph is initialized.
	// TODO: Use host.Init(). It is not used in this example to prevent circular
	// go package import.
	if _, err := driverreg.Init(); err != nil {
		log.Fatal(err)
	}

	// Use spireg SPI port registry to find the first available SPI bus.
	p, err := spireg.Open("")
	if err != nil {
		log.Fatal(err)
	}
	defer p.Close()

	// Convert the spi.Port into a spi.Conn so it can be used for communication.
	c, err := p.Connect(physic.MegaHertz, spi.Mode3, 8)
	if err != nil {
		log.Fatal(err)
	}

	// Prints out the gpio pin used.
	if p, ok := c.(spi.Pins); ok {
		fmt.Printf("  CLK : %s", p.CLK())
		fmt.Printf("  MOSI: %s", p.MOSI())
		fmt.Printf("  MISO: %s", p.MISO())
		fmt.Printf("  CS  : %s", p.CS())
	}
}