Initial support for MAX7219 (gpio) led driver

drivers/gpio/max7219_driver.go

@@ -0,0 +1,155 @@
+package gpio
+
+import (
+	"gobot.io/x/gobot"
+)
+
+const (
+	MAX7219Digit0 = 0x01
+	MAX7219Digit1 = 0x02
+	MAX7219Digit2 = 0x03
+	MAX7219Digit3 = 0x04
+	MAX7219Digit4 = 0x05
+	MAX7219Digit5 = 0x06
+	MAX7219Digit6 = 0x07
+	MAX7219Digit7 = 0x08
+
+	MAX7219DecodeMode  = 0x09
+	MAX7219Intensity   = 0x0a
+	MAX7219ScanLimit   = 0x0b
+	MAX7219Shutdown    = 0x0c
+	MAX7219DisplayTest = 0x0f
+)
+
+// MAX7219Driver is the gobot driver for the MAX7219 LED driver
+//
+// Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX7219-MAX7221.pdf
+type MAX7219Driver struct {
+	pinClock   *DirectPinDriver
+	pinData    *DirectPinDriver
+	pinCS      *DirectPinDriver
+	name       string
+	count      uint
+	connection gobot.Connection
+	gobot.Commander
+}
+
+// NewMAX7219Driver return a new MAX7219Driver given a gobot.Connection, pins and how many chips are chained
+func NewMAX7219Driver(a gobot.Connection, clockPin string, dataPin string, csPin string, count uint) *MAX7219Driver {
+	t := &MAX7219Driver{
+		name:       gobot.DefaultName("MAX7219Driver"),
+		pinClock:   NewDirectPinDriver(a, clockPin),
+		pinData:    NewDirectPinDriver(a, dataPin),
+		pinCS:      NewDirectPinDriver(a, csPin),
+		count:      count,
+		connection: a,
+		Commander:  gobot.NewCommander(),
+	}
+
+	/* TODO : Add commands */
+
+	return t
+}
+
+// Start initializes the max7219, it uses a SPI-like communication protocol
+func (a *MAX7219Driver) Start() (err error) {
+	a.pinData.On()
+	a.pinClock.On()
+	a.pinCS.On()
+
+	a.All(MAX7219ScanLimit, 0x07)
+	a.All(MAX7219DecodeMode, 0x00)
+	a.All(MAX7219Shutdown, 0x01)
+	a.All(MAX7219DisplayTest, 0x00)
+	a.ClearAll()
+	a.All(MAX7219Intensity, 0x0f&0x0f)
+
+	return
+}
+
+// Halt implements the Driver interface
+func (a *MAX7219Driver) Halt() (err error) { return }
+
+// Name returns the MAX7219Drivers name
+func (a *MAX7219Driver) Name() string { return a.name }
+
+// SetName sets the MAX7219Drivers name
+func (a *MAX7219Driver) SetName(n string) { a.name = n }
+
+// Connection returns the MAX7219Driver Connection
+func (a *MAX7219Driver) Connection() gobot.Connection {
+	return a.connection
+}
+
+// SetIntensity changes the intensity (from 1 to 7) of the display
+func (a *MAX7219Driver) SetIntensity(level byte) {
+	if level > 15 {
+		level = 15
+	}
+	a.All(MAX7219Intensity, level&level)
+}
+
+// ClearAll turns off all LEDs of all modules
+func (a *MAX7219Driver) ClearAll() {
+	for i := 1; i <= 8; i++ {
+		a.All(byte(i), 0)
+	}
+}
+
+// ClearAll turns off all LEDs of the given module
+func (a *MAX7219Driver) ClearOne(which uint) {
+	for i := 1; i <= 8; i++ {
+		a.One(which, byte(i), 0)
+	}
+}
+
+// sendData is an auxiliary function to send data to the MAX7219Driver module
+func (a *MAX7219Driver) sendData(address byte, data byte) {
+	a.pinCS.Off()
+	a.send(address)
+	a.send(data)
+	a.pinCS.On()
+}
+
+// send writes data on the module
+func (a *MAX7219Driver) send(data byte) {
+	var i byte
+	for i = 8; i > 0; i-- {
+		mask := byte(0x01 << (i - 1))
+
+		a.pinClock.Off()
+		if data&mask > 0 {
+			a.pinData.On()
+		} else {
+			a.pinData.Off()
+		}
+		a.pinClock.On()
+	}
+}
+
+// All sends the same data to all the modules
+func (a *MAX7219Driver) All(address byte, data byte) {
+	a.pinCS.Off()
+	var c uint
+	for c = 0; c < a.count; c++ {
+		a.send(address)
+		a.send(data)
+	}
+	a.pinCS.On()
+}
+
+// One sends data to a specific module
+func (a *MAX7219Driver) One(which uint, address byte, data byte) {
+	a.pinCS.Off()
+	var c uint
+	for c = 0; c < a.count; c++ {
+		if c == which {
+			a.send(address)
+			a.send(data)
+		} else {
+			a.send(0)
+			a.send(0)
+		}
+	}
+	a.pinCS.On()
+}

drivers/gpio/max7219_driver_test.go

@@ -0,0 +1,52 @@
+package gpio
+
+import (
+	"strings"
+	"testing"
+
+	"gobot.io/x/gobot"
+	"gobot.io/x/gobot/gobottest"
+)
+
+var _ gobot.Driver = (*MAX7219Driver)(nil)
+
+// --------- HELPERS
+func initTestMAX7219Driver() (driver *MAX7219Driver) {
+	driver, _ = initTestMAX7219DriverWithStubbedAdaptor()
+	return
+}
+
+func initTestMAX7219DriverWithStubbedAdaptor() (*MAX7219Driver, *gpioTestAdaptor) {
+	adaptor := newGpioTestAdaptor()
+	return NewMAX7219Driver(adaptor, "1", "2", "3", 1), adaptor
+}
+
+// --------- TESTS
+func TestMAX7219Driver(t *testing.T) {
+	var a interface{} = initTestMAX7219Driver()
+	_, ok := a.(*MAX7219Driver)
+	if !ok {
+		t.Errorf("NewMAX7219Driver() should have returned a *MAX7219Driver")
+	}
+}
+
+func TestMAX7219DriverStart(t *testing.T) {
+	d := initTestMAX7219Driver()
+	gobottest.Assert(t, d.Start(), nil)
+}
+
+func TestMAX7219DriverHalt(t *testing.T) {
+	d := initTestMAX7219Driver()
+	gobottest.Assert(t, d.Halt(), nil)
+}
+
+func TestMAX7219DriverDefaultName(t *testing.T) {
+	d := initTestMAX7219Driver()
+	gobottest.Assert(t, strings.HasPrefix(d.Name(), "MAX7219Driver"), true)
+}
+
+func TestMAX7219DriverSetName(t *testing.T) {
+	d := initTestMAX7219Driver()
+	d.SetName("mybot")
+	gobottest.Assert(t, d.Name(), "mybot")
+}

examples/firmata_gpio_max7219.go

@@ -0,0 +1,66 @@
+// +build example
+//
+// Do not build by default.
+
+/*
+ How to setup
+ This examples requires you to daisy-chain 4 led matrices based on MAX7219.
+ It will turn on one led at a time, from the first led at the first matrix to the last led of the last matrix.
+
+ How to run
+ Pass serial port to use as the first param:
+
+	go run examples/firmata_gpio_max7219.go /dev/ttyACM0
+*/
+
+package main
+
+import (
+	"os"
+	"time"
+
+	"gobot.io/x/gobot"
+	"gobot.io/x/gobot/drivers/gpio"
+	"gobot.io/x/gobot/platforms/firmata"
+)
+
+func main() {
+	firmataAdaptor := firmata.NewAdaptor(os.Args[1])
+	max := gpio.NewMAX7219Driver(firmataAdaptor, "11", "10", "9", 4)
+
+	var digit byte = 1 // digit address goes from 0x01 (MAX7219Digit0) to 0x08 (MAX7219Digit8)
+	var bits byte = 1
+	var module uint
+	count := 0
+
+	work := func() {
+		gobot.Every(100*time.Millisecond, func() {
+			max.ClearAll()
+			max.One(module, digit, bits)
+			bits = bits << 1
+
+			count++
+			if count > 7 {
+				count = 0
+				digit++
+				bits = 1
+				if digit > 8 {
+					digit = 1
+					module++
+					if module >= 4 {
+						module = 0
+						count = 0
+					}
+				}
+			}
+		})
+	}
+
+	robot := gobot.NewRobot("Max7219Bot",
+		[]gobot.Connection{esp8266},
+		[]gobot.Device{max},
+		work,
+	)
+
+	robot.Start()
+}