drivers: add driver for IS31FL3731 matrix LED driver (#370)

IS31FL3731: add driver for IS31FL3731 matrix LED driver

examples/is31fl3731/main.go

@@ -0,0 +1,51 @@
+package main
+
+import (
+	"time"
+
+	"machine"
+
+	"tinygo.org/x/drivers/is31fl3731"
+)
+
+// I2CAddress -- address of led matrix
+var I2CAddress uint8 = is31fl3731.I2C_ADDRESS_74
+
+func main() {
+	bus := machine.I2C0
+	err := bus.Configure(machine.I2CConfig{})
+	if err != nil {
+		println("could not configure I2C:", err)
+		return
+	}
+
+	// Create driver for Adafruit 15x7 CharliePlex LED Matrix FeatherWing
+	// (CharlieWing): https://www.adafruit.com/product/3163
+	ledMatrix := is31fl3731.NewAdafruitCharlieWing15x7(bus, I2CAddress)
+
+	err = ledMatrix.Configure()
+	if err != nil {
+		println("could not configure is31fl3731 driver:", err)
+		return
+	}
+
+	// Fill the whole matrix on the frame #0 (visible by default)
+	ledMatrix.Fill(is31fl3731.FRAME_0, uint8(3))
+
+	// Draw couple pixels on the frame #1 (not visible yet)
+	ledMatrix.DrawPixelXY(is31fl3731.FRAME_1, uint8(0), uint8(0), uint8(10))
+	ledMatrix.DrawPixelXY(is31fl3731.FRAME_1, uint8(14), uint8(6), uint8(10))
+
+	// There are 8 frames available, it's a good idea to draw on an invisible
+	// frame and then switch to that frame to reduce flickering. Switch between
+	// frame #0 and #1 in a loop to show animation:
+	for {
+		println("show frame #0...")
+		ledMatrix.SetActiveFrame(is31fl3731.FRAME_0)
+		time.Sleep(time.Second * 3)
+
+		println("show frame #1...")
+		ledMatrix.SetActiveFrame(is31fl3731.FRAME_1)
+		time.Sleep(time.Second * 3)
+	}
+}