Add parallel port comms to arduino

arduino/kbd/parallel.h

@@ -0,0 +1,14 @@
+#pragma once
+
+#include <stdint.h>
+
+/** Returns the byte present on D0~D7 */
+uint8_t readParallel();
+
+/** Writes a nibble on status pins */
+void writeParallel(uint8_t nibble);
+
+void setupParallel();
+
+/** Returns true and sets the byte if a strobe was received */
+bool strobeOccurred(uint8_t &byte);