Shiftregister implementation (#135)

* Basic support of SIPO shift register

* typo

* add example of shiftregister for arduino and nucleo

* Fix build flag for nucleof103rb

* Fix wrong data pin configuration

* Change README.md for Shift registers

* Add API for individual register's output pin

* Rewrite shift register example to show ShiftPin usage

* Fix target for shiftregister example smoke test

* Fix type in makefile

* Add shiftregister compatble IC

* Edit comment and readme

Makefile

@@ -121,5 +121,7 @@ smoke-test:
 	@md5sum ./build/test.hex
 	tinygo build -size short -o ./build/test.hex -target=arduino-nano33 ./examples/l9110x/speed/main.go
 	@md5sum ./build/test.hex
+	tinygo build -size short -o ./build/test.hex -target=nucleo-f103rb ./examples/shiftregister/main.go
+	@md5sum ./build/test.hex
 
 test: clean fmt-check smoke-test

README.md

@@ -87,7 +87,8 @@ The following 44 devices are supported.
 | [PCD8544 display](http://eia.udg.edu/~forest/PCD8544_1.pdf) | SPI |
 | [Resistive Touchscreen (4-wire)](http://ww1.microchip.com/downloads/en/Appnotes/doc8091.pdf) | GPIO |
 | [Semihosting](https://wiki.segger.com/Semihosting) | Debug |
-| [Shift register](https://en.wikipedia.org/wiki/Shift_register#Parallel-in_serial-out_\(PISO\)) | GPIO |
+| [Shift register (PISO)](https://en.wikipedia.org/wiki/Shift_register#Parallel-in_serial-out_\(PISO\)) | GPIO |
+| [Shift registers (SIPO)](https://en.wikipedia.org/wiki/Shift_register#Serial-in_parallel-out_(SIPO)) | GPIO |
 | [SHT3x Digital Humidity Sensor](https://www.sensirion.com/fileadmin/user_upload/customers/sensirion/Dokumente/0_Datasheets/Humidity/Sensirion_Humidity_Sensors_SHT3x_Datasheet_digital.pdf) | I2C |
 | [SSD1306 OLED display](https://cdn-shop.adafruit.com/datasheets/SSD1306.pdf) | I2C / SPI |
 | [SSD1331 TFT color display](https://www.crystalfontz.com/controllers/SolomonSystech/SSD1331/381/) | SPI |

examples/shiftregister/main.go

@@ -0,0 +1,124 @@
+package main
+
+import (
+	"machine"
+	"time"
+
+	"tinygo.org/x/drivers/shiftregister"
+)
+
+func main() {
+	d := shiftregister.New(
+		shiftregister.EIGHT_BITS,
+		machine.PA6, // D12 Pin latch connected to ST_CP of 74HC595 (12)
+		machine.PA7, // D11 Pin clock connected to SH_CP of 74HC595 (11)
+		machine.PB6, // D10 Pin data connected to DS of 74HC595 (14)
+	)
+	d.Configure()
+
+	for {
+
+		// Examples using masks. This method writes all pins state at once.
+
+		// All pins High
+		d.WriteMask(0xFF)
+		delay()
+
+		// All pins Low
+		d.WriteMask(0x00)
+		delay()
+
+		// Some fun with masks
+		for _, pattern := range patterns {
+			d.WriteMask(pattern)
+			shortDelay()
+		}
+		delay()
+		d.WriteMask(0x00)
+
+		// Examples using individually addressable pin API. This method is slower than using mask
+		// because all register's pins state are send for is p.Set() call.
+
+		// Set register's pin #4
+		d.GetShiftPin(4).High()
+		delay()
+		d.GetShiftPin(4).Low()
+		delay()
+
+		// Get an individual pin and use it
+		pin := d.GetShiftPin(7)
+		pin.High()
+		delay()
+		pin.Low()
+		delay()
+
+		// Prepare an array of pin attached to the register
+		pins := [8]*shiftregister.ShiftPin{}
+		for p := 0; p < 8; p++ {
+			pins[p] = d.GetShiftPin(p)
+		}
+
+		for p := 7; p >= 0; p-- {
+			pins[p].Low()
+			shortDelay()
+			pins[p].High()
+		}
+
+		for p := 7; p >= 0; p-- {
+			pins[p].High()
+			time.Sleep(100 * time.Millisecond)
+			pins[p].Low()
+		}
+		delay()
+	}
+}
+
+func delay() {
+	time.Sleep(500 * time.Millisecond)
+}
+func shortDelay() {
+	time.Sleep(100 * time.Millisecond)
+}
+
+var patterns = []uint32{
+	0b00000001,
+	0b00000010,
+	0b00000100,
+	0b00001000,
+	0b00010000,
+	0b00100000,
+	0b01000000,
+	0b10000000,
+	0b10000001,
+	0b10000010,
+	0b10000100,
+	0b10001000,
+	0b10010000,
+	0b10100000,
+	0b11000000,
+	0b11000001,
+	0b11000010,
+	0b11000100,
+	0b11001000,
+	0b11010000,
+	0b11100000,
+	0b11100001,
+	0b11100010,
+	0b11100100,
+	0b11101000,
+	0b11110000,
+	0b11110001,
+	0b11110010,
+	0b11110100,
+	0b11111000,
+	0b11111001,
+	0b11111010,
+	0b11111100,
+	0b11111101,
+	0b11111110,
+	0b11111111,
+	0b00000000,
+	0b11111111,
+	0b00000000,
+	0b11111111,
+}

shiftregister/shiftregister.go

@@ -0,0 +1,93 @@
+// Package shiftregister is for 8bit shift output register using 3 GPIO pins like SN74ALS164A, SN74AHC594, SN74AHC595, ...
+package shiftregister
+
+import (
+	"machine"
+)
+
+type NumberBit int8
+
+// Bit number of the register
+const (
+	EIGHT_BITS     NumberBit = 8
+	SIXTEEN_BITS   NumberBit = 16
+	THIRTYTWO_BITS NumberBit = 32
+)
+
+// Device holds pin number
+type Device struct {
+	latch, clock, out machine.Pin // IC wiring
+	bits              NumberBit   // Pin number
+	mask              uint32      // keep all pins state
+}
+
+// ShiftPin is the implementation of the ShiftPin interface.
+// ShiftPin provide an interface like regular machine.Pin
+type ShiftPin struct {
+	mask uint32  // Bit representing the pin
+	d    *Device // Reference to the register
+}
+
+// New returns a new shift output register device
+func New(Bits NumberBit, Latch, Clock, Out machine.Pin) *Device {
+	return &Device{
+		latch: Latch,
+		clock: Clock,
+		out:   Out,
+		bits:  Bits,
+	}
+}
+
+// Configure set hardware configuration
+func (d *Device) Configure() {
+	d.latch.Configure(machine.PinConfig{Mode: machine.PinOutput})
+	d.clock.Configure(machine.PinConfig{Mode: machine.PinOutput})
+	d.out.Configure(machine.PinConfig{Mode: machine.PinOutput})
+	d.latch.High()
+}
+
+// WriteMask applies mask's bits to register's outputs pin
+// mask's MSB set Q1, LSB set Q8 (for 8 bits mask)
+func (d *Device) WriteMask(mask uint32) {
+	d.mask = mask // Keep the mask for individual addressing
+	d.latch.Low()
+	for i := 0; i < int(d.bits); i++ {
+		d.clock.Low()
+		d.out.Set(mask&1 != 0)
+		mask = mask >> 1
+		d.clock.High()
+	}
+	d.latch.High()
+}
+
+// GetShiftPin return an individually addressable pin
+func (d *Device) GetShiftPin(pin int) *ShiftPin {
+	if pin < 0 || pin > int(d.bits) {
+		panic("invalid pin number")
+	}
+	return &ShiftPin{
+		mask: 1 << pin,
+		d:    d,
+	}
+
+}
+
+// Set changes the value of this register pin.
+func (p ShiftPin) Set(value bool) {
+	d := p.d
+	if value {
+		d.WriteMask(d.mask | p.mask)
+	} else {
+		d.WriteMask(d.mask & ^p.mask)
+	}
+}
+
+// High sets this shift register pin to high.
+func (p ShiftPin) High() {
+	p.Set(true)
+}
+
+// Low sets this shift register pin to low.
+func (p ShiftPin) Low() {
+	p.Set(false)
+}