Remove microbit matrix (#319)

* Remove matrix code from bbc:microbit, and move it to a driver

src/examples/microbit-blink/microbit-blink.go

@@ -1,4 +1,4 @@
-// blink program for the BBC micro:bit that uses the entire LED matrix
+// blink program for the BBC micro:bit
 package main
 
 import (
@@ -6,14 +6,19 @@ import (
 	"time"
 )
 
+// The LED matrix in the micro:bit is a multiplexed display: https://en.wikipedia.org/wiki/Multiplexed_display
+// Driver for easier control: https://github.com/tinygo-org/drivers/tree/master/microbitmatrix
 func main() {
-	machine.InitLEDMatrix()
-
+	ledrow := machine.GPIO{machine.LED_ROW_1}
+	ledrow.Configure(machine.GPIOConfig{Mode: machine.GPIO_OUTPUT})
+	ledcol := machine.GPIO{machine.LED_COL_1}
+	ledcol.Configure(machine.GPIOConfig{Mode: machine.GPIO_OUTPUT})
+	ledcol.Low()
 	for {
-		machine.ClearLEDMatrix()
+		ledrow.Low()
 		time.Sleep(time.Millisecond * 500)
 
-		machine.SetEntireLEDMatrixOn()
+		ledrow.High()
 		time.Sleep(time.Millisecond * 500)
 	}
 }

src/machine/board_microbit.go

@@ -2,11 +2,6 @@
 
 package machine
 
-import (
-	"device/nrf"
-	"errors"
-)
-
 // The micro:bit does not have a 32kHz crystal on board.
 const HasLowFrequencyCrystal = false
 
@@ -79,65 +74,3 @@ const (
 	LED_ROW_2 = 14
 	LED_ROW_3 = 15
 )
-
-// matrixSettings has the legs of the LED grid in the form {row, column} for each LED position.
-var matrixSettings = [5][5][2]uint8{
-	{{LED_ROW_1, LED_COL_1}, {LED_ROW_2, LED_COL_4}, {LED_ROW_1, LED_COL_2}, {LED_ROW_2, LED_COL_5}, {LED_ROW_1, LED_COL_3}},
-	{{LED_ROW_3, LED_COL_4}, {LED_ROW_3, LED_COL_5}, {LED_ROW_3, LED_COL_6}, {LED_ROW_3, LED_COL_7}, {LED_ROW_3, LED_COL_8}},
-	{{LED_ROW_2, LED_COL_2}, {LED_ROW_1, LED_COL_9}, {LED_ROW_2, LED_COL_3}, {LED_ROW_3, LED_COL_9}, {LED_ROW_2, LED_COL_1}},
-	{{LED_ROW_1, LED_COL_8}, {LED_ROW_1, LED_COL_7}, {LED_ROW_1, LED_COL_6}, {LED_ROW_1, LED_COL_5}, {LED_ROW_1, LED_COL_4}},
-	{{LED_ROW_3, LED_COL_3}, {LED_ROW_2, LED_COL_7}, {LED_ROW_3, LED_COL_1}, {LED_ROW_2, LED_COL_6}, {LED_ROW_3, LED_COL_2}}}
-
-// InitLEDMatrix initializes the LED matrix, by setting all of the row/col pins to output
-// then calling ClearLEDMatrix.
-func InitLEDMatrix() {
-	set := 0
-	for i := LED_COL_1; i <= LED_ROW_3; i++ {
-		set |= 1 << uint8(i)
-	}
-	nrf.GPIO.DIRSET = nrf.RegValue(set)
-	ClearLEDMatrix()
-}
-
-// ClearLEDMatrix clears the entire LED matrix.
-func ClearLEDMatrix() {
-	set := 0
-	for i := LED_COL_1; i <= LED_COL_9; i++ {
-		set |= 1 << uint8(i)
-	}
-	nrf.GPIO.OUTSET = nrf.RegValue(set)
-	nrf.GPIO.OUTCLR = (1 << LED_ROW_1) | (1 << LED_ROW_2) | (1 << LED_ROW_3)
-}
-
-// SetLEDMatrix turns on a single LED on the LED matrix.
-// Currently limited to a single LED at a time, it will clear the matrix before setting it.
-func SetLEDMatrix(x, y uint8) error {
-	if x > 4 || y > 4 {
-		return errors.New("Invalid LED matrix row or column")
-	}
-
-	// Clear matrix
-	ClearLEDMatrix()
-
-	nrf.GPIO.OUTSET = (1 << matrixSettings[y][x][0])
-	nrf.GPIO.OUTCLR = (1 << matrixSettings[y][x][1])
-
-	return nil
-}
-
-// SetEntireLEDMatrixOn turns on all of the LEDs on the LED matrix.
-func SetEntireLEDMatrixOn() error {
-	set := 0
-	for i := LED_ROW_1; i <= LED_ROW_3; i++ {
-		set |= 1 << uint8(i)
-	}
-	nrf.GPIO.OUTSET = nrf.RegValue(set)
-
-	set = 0
-	for i := LED_COL_1; i <= LED_COL_9; i++ {
-		set |= 1 << uint8(i)
-	}
-	nrf.GPIO.OUTCLR = nrf.RegValue(set)
-
-	return nil
-}