reelboard: support Reel Board (nrf52840 dev board)

Signed-off-by: Ron Evans <ron@hybridgroup.com>

src/machine/board_reelboard.go

@@ -0,0 +1,35 @@
+// +build reelboard
+
+package machine
+
+const HasLowFrequencyCrystal = true
+
+// LEDs on the reel board
+const (
+	LED        = LED1
+	LED1       = LED_YELLOW
+	LED2       = LED_RED
+	LED3       = LED_GREEN
+	LED4       = LED_BLUE
+	LED_RED    = 11
+	LED_GREEN  = 12
+	LED_BLUE   = 41
+	LED_YELLOW = 13
+)
+
+// User "a" button on the reel board
+const (
+	BUTTON = 7
+)
+
+// UART pins
+const (
+	UART_TX_PIN = 6
+	UART_RX_PIN = 8
+)
+
+// I2C pins
+const (
+	SDA_PIN = 26
+	SCL_PIN = 27
+)