RE: [Rcxemul-discussion] Strange things afoot

[David E. <d.a...@du...>]

Finally figured it out!

A bug in my bit operation instructions meant that instead of changing a
bit in the byte at a specified memory address, it would read a word from
this memory address and use that word as the address of the byte to
alter. It just so happened that at that moment, 0xA00A was in the word
at that memory address, so it cleared a bit in the byte at 0xA00A. Hence
0x1D became 0x15. The offending instruction was in a periodic update of
the LCD.

My next job is to work out if the firmware is being executed. If it is,
I'll need to have a look at the lejos code to work out what should
happen after it has been downloaded.