(incidentally, why has the title of this thread mutated? ;-) ) On Fri, 11 Nov 1994 11:24:04 +0000 (GMT), Simon Cooke said: > Simple -- it would require a sum total of about... ooh let me think... > approximately 16-18 more pins for access to the memory by the ASIC...
Well, in that case the ASIC could have been split into two, with one being purely for the screen and the other for everything else (well I'm not an ASIC expert so I don't actually know what I'm talking about...). But anyway, even if it was just 32K of memory in a separate chip (refreshed by the Z80 itself, perhaps), it would have been nice to have somewhere to put routines where they wouldn't have the timing messed about with (which reminds me... my PLAY command seems to work, but now I think about it I didn't do any compensating in the timing routine for this contended memory lark so if it works properly it's just a fluke, and it will need adjusting if it is placed in ROM...). If it were to be arranged properly, it might even allow a Spectrum emulator to have the ROM in a non-contended page (although that's a bit more difficulat than it should be because the Sam doesn't allow sections A and B to be paged separately). > The only reason the SAM doesn't have more colours in its palette is because > of lack of pins. The same with most things you can think of that are missing > on it -- Bruce ran out of pins on the ASIC and had to cut stuff out. And he still didn't prefer a separate graphics processor? imc PS the directory where I put the files for you has a 30-day expire period, so don't leave it too long, Si. :-)
