Added Gopher ARCADE board

GNUmakefile

@@ -795,6 +795,8 @@ endif
 	@$(MD5SUM) test.hex
 	$(TINYGO) build -size short -o test.hex -target=gopher-badge      examples/blinky1
 	@$(MD5SUM) test.hex
+	$(TINYGO) build -size short -o test.hex -target=gopher-arcade      examples/blinky1
+	@$(MD5SUM) test.hex
 	$(TINYGO) build -size short -o test.hex -target=ae-rp2040           examples/echo
 	@$(MD5SUM) test.hex
 	$(TINYGO) build -size short -o test.hex -target=thumby              examples/echo

src/machine/board_gopher-arcade.go

@@ -0,0 +1,22 @@
+//go:build gopher_arcade
+
+package machine
+
+// Return the current CPU frequency in hertz.
+func CPUFrequency() uint32 {
+	return 8000000
+}
+
+const (
+	P5 Pin = PB0
+	P6 Pin = PB1
+	P7 Pin = PB2
+	P2 Pin = PB3
+	P3 Pin = PB4
+	P1 Pin = PB5
+
+	LED          = P1
+	BUTTON_LEFT  = P7
+	BUTTON_RIGHT = P5
+	SPEAKER      = P6
+)

targets/gopher-arcade.json

@@ -0,0 +1,10 @@
+{
+	"inherits": ["attiny85"],
+	"build-tags": ["gopher_arcade"],
+	"ldflags": [
+		"--defsym=_bootloader_size=2180",
+		"--defsym=_stack_size=128"
+	],
+	"flash-command": "avrdude -c usbasp -p t85 -B 10 -U flash:w:{hex}:i",
+	"emulator": "simavr -m attiny85 -f 16000000 {}"
+}