On Thu, 22 Jun 2000 14:24:31 +0200 (CEST), ag0ny wrote:
>> One solution is to use dual ported RAM (RAM ICs that can handle two
>> accesses at the same time). I heard this type of RAM is expensive, but I'm
>> not sure if that's also true for small amounts (128K).
>Padial uses a *1Kb* biport memory chip for his Z380 board, so Z80 and Z380
>can communicate. This memory is VERY expensive, so I think this is not a
>good solution to the problem.
Ademir has already make a solution and it works. It's not expensive and
it's very fast! You do not need to access memory twice at the same time.
The time V99x8 "hangs" the memory is very little. There a big "window" of
time to Z80/Z180/Z380 access video ram. Everything is needed is a fast
static ram and a good circuit to sinchronize everything. This is the way
Ademir has done it.
>> In my view, there is only one big disadvantage of direct VRAM access:
>> existing MSXes don't have it.
>I agree. :)
In ADVRAM case, you'll just need to install it. And I can speek
for ya: if you need to use RAM->VRAM copy, you'll make these operations
at least TWICE FASTER even on 3.57 Z80. I'm talking AT LEAST. Real
numbers. (-:
----- Abra�OS/2, Daniel Caetano ([EMAIL PROTECTED])
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...Programar e' a arte de organizar zeros e uns de forma que eles produzam trabalho
util!
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