On Fri, 10 Feb 1995 14:01:20 +0000 (GMT), [EMAIL PROTECTED] said: > If we are going to the trouble of shadow ram and all > the paging and refreshing nonsense that that involves, > why not just build a faster video display - just modes > 3 and 4 for simplicity. Then there's no need to replace > the RAM, and the colour encoder is already there.
"faster video display" - what's that? Clearly it has to output the picture at the same speed if it wants a TV to understand it, and since it needs to read 4 bytes of the display every 8 T-states, allowing the CPU one read every 8 cycles is probably quite generous. Besides which, you seem to be forgetting that if you want to use the Sam's existing RAM in a way which does not cause delays then you will have to work quite hard to prevent the ASIC from introducing WAIT states. imc
