Yesterday we finally got the IRQ-handler working on the stage 2 board! 

That means that all features of stage 2 is tested and working properly. My son is now focusing on writing a SREC parser for our serial routines so we can simplifying testing of applications. No more flashing and swapping EEProms! And the final thing to test is the PS2 interface I built as an expansion for the Stage 1 board. At least I was smart to build the PS2 board so it would be possible to test stand alone, without any computer connected to it so I can test it without starting the Stage 1 board again! That one is relegated to the dusty shelf of history now!