atsame5x: add support for CAN

src/examples/can/feather-m4-can.go

@@ -0,0 +1,15 @@
+// +build feather_m4_can
+
+package main
+
+import (
+	"machine"
+)
+
+func init() {
+	// power on the CAN Transceiver
+	// https://learn.adafruit.com/adafruit-feather-m4-can-express/pinouts#can-bus-3078990-8
+	boost_en := machine.BOOST_EN
+	boost_en.Configure(machine.PinConfig{Mode: machine.PinOutput})
+	boost_en.High()
+}