RetroChallenge 2017/10 – More clues but what do they mean?

So here we are, two thirds of the way through the month and the Nascom-1 is looking just as it did when I started 🙂

But now, take a look at this picture…

This is the Nascom with a ROM in it that fills the screen with NULLs. I’ve just pressed reset.


Now look at this photo…

This is a different ROM. This  one fills the screen with ‘*’s. Again I’ve just pressed reset.

Their behaviour with these ROMs after reset is pretty consistant but not guaranteed.

But what does it mean?

I don’t know, but I’m sure it means something. It could mean I’ve mucked up the ROMs. As 2708s are hard to find and program, I’m using a 2716 in a little adapter that I made myself but they look fine.

With the alternative ROMs in place, we’re only using the screen RAM and the addressing logic, buffers etc.

 

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