added driver for ST7789 TFT color display (#76)

Makefile

@@ -38,6 +38,7 @@ smoke-test:
 	tinygo build -size short -o ./build/test.elf -target=microbit ./examples/ssd1306/i2c_128x32/main.go
 	tinygo build -size short -o ./build/test.elf -target=microbit ./examples/ssd1306/spi_128x64/main.go
 	tinygo build -size short -o ./build/test.elf -target=microbit ./examples/st7735/main.go
+	tinygo build -size short -o ./build/test.elf -target=microbit ./examples/st7789/main.go
 	tinygo build -size short -o ./build/test.elf -target=circuitplay-express ./examples/thermistor/main.go
 	tinygo build -size short -o ./build/test.elf -target=itsybitsy-m0 ./examples/vl53l1x/main.go
 	tinygo build -size short -o ./build/test.elf -target=microbit ./examples/waveshare-epd/epd2in13/main.go

README.md

@@ -78,6 +78,7 @@ func main() {
 | [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 |
 | [ST7735 TFT color display](https://www.crystalfontz.com/controllers/Sitronix/ST7735R/319/) | SPI |
+| [ST7789 TFT color display](https://cdn-shop.adafruit.com/product-files/3787/3787_tft_QT154H2201__________20190228182902.pdf) | SPI |
 | [Thermistor](https://www.farnell.com/datasheets/33552.pdf) | ADC |
 | [VL53L1X time-of-flight distance sensor](https://www.st.com/resource/en/datasheet/vl53l1x.pdf) | I2C |
 | [Waveshare 2.13" e-paper display](https://www.waveshare.com/w/upload/e/e6/2.13inch_e-Paper_Datasheet.pdf) | SPI |

examples/st7789/main.go

@@ -0,0 +1,34 @@
+package main
+
+import (
+	"machine"
+
+	"image/color"
+
+	"tinygo.org/x/drivers/st7789"
+)
+
+func main() {
+	machine.SPI0.Configure(machine.SPIConfig{
+		Frequency: 8000000,
+		Mode:      3,
+	})
+	display := st7789.New(machine.SPI0, machine.P6, machine.P7, machine.P8)
+	display.Configure(st7789.Config{Rotation: st7789.NO_ROTATION})
+
+	width, height := display.Size()
+
+	white := color.RGBA{255, 255, 255, 255}
+	red := color.RGBA{255, 0, 0, 255}
+	blue := color.RGBA{0, 0, 255, 255}
+	green := color.RGBA{0, 255, 0, 255}
+	black := color.RGBA{0, 0, 0, 255}
+
+	display.FillScreen(black)
+
+	display.FillRectangle(0, 0, width/2, height/2, white)
+	display.FillRectangle(width/2, 0, width/2, height/2, red)
+	display.FillRectangle(0, height/2, width/2, height/2, green)
+	display.FillRectangle(width/2, height/2, width/2, height/2, blue)
+	display.FillRectangle(width/4, height/4, width/2, height/2, black)
+}

st7789/registers.go

@@ -0,0 +1,54 @@
+package st7789
+
+// Registers
+const (
+	NOP        = 0x00
+	SWRESET    = 0x01
+	RDDID      = 0x04
+	RDDST      = 0x09
+	SLPIN      = 0x10
+	SLPOUT     = 0x11
+	PTLON      = 0x12
+	NORON      = 0x13
+	INVOFF     = 0x20
+	INVON      = 0x21
+	DISPOFF    = 0x28
+	DISPON     = 0x29
+	CASET      = 0x2A
+	RASET      = 0x2B
+	RAMWR      = 0x2C
+	RAMRD      = 0x2E
+	PTLAR      = 0x30
+	COLMOD     = 0x3A
+	MADCTL     = 0x36
+	MADCTL_MY  = 0x80
+	MADCTL_MX  = 0x40
+	MADCTL_MV  = 0x20
+	MADCTL_ML  = 0x10
+	MADCTL_RGB = 0x00
+	MADCTL_BGR = 0x08
+	MADCTL_MH  = 0x04
+	RDID1      = 0xDA
+	RDID2      = 0xDB
+	RDID3      = 0xDC
+	RDID4      = 0xDD
+	FRMCTR1    = 0xB1
+	FRMCTR2    = 0xB2
+	FRMCTR3    = 0xB3
+	INVCTR     = 0xB4
+	DISSET5    = 0xB6
+	PWCTR1     = 0xC0
+	PWCTR2     = 0xC1
+	PWCTR3     = 0xC2
+	PWCTR4     = 0xC3
+	PWCTR5     = 0xC4
+	VMCTR1     = 0xC5
+	PWCTR6     = 0xFC
+	GMCTRP1    = 0xE0
+	GMCTRN1    = 0xE1
+
+	NO_ROTATION  Rotation = 0
+	ROTATION_90  Rotation = 1 // 90 degrees clock-wise rotation
+	ROTATION_180 Rotation = 2
+	ROTATION_270 Rotation = 3
+)