[SiriusHardware]

Hmm, and we imposed at least one major spec change pretty late on, namely the ability for any control input to respond to a change in state of TOP PAGE half way down the screen.

The changes you are considering making to de-shudder the graphics mode I think I understand in principle - leave it at the higher baud rate and use two serial bits to represent each pixel although presumably that means you would have to pre-store a further 256 +256 'characters' (the high and low nibbles of each possible bit pattern, with each pixel represented by 2 bits?).

If you wanted to say 'Look, just use the 877 and forget about the 877A' I don't think we would quibble too much about that as long as that requirement, and the unsuitability of the 877A, was made clear in the project documentation.

Can I ask, though, if you have a theory as to why this was not a problem even on the 877A in your first two released firmware versions? No shudder in those versions, and I have only used the 877A throughout.