[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Installing GS RAM card in slots 1-7
"Alex Freed" <alex_news@mirrow.com> wrote in message
news:hti2lt$jlf$1@adenine.netfront.net...
>>
>> To maybe answer my own question: I suppose the CB card is
>> picking up the writes that a program is making to the video
>> memory and using that to generate the VGA output. If that is the
>> case then I needn't be concerned with the concurrent accesses to
>> AUX memory and main memory.
>>
>
> Correct. The CB card has its own memory and very fast one at that.
> And wide.
> All the video data written by the 6502 appears on the same bus and
> goes into the odd and even banks depending on the soft switches
> that the CB also understands.
Thanks for confirming that.
> So displaying DHR graphics by CB is not too difficult - the basic
> timing is mostly the same as the 80 col text mode. The reason I
> didn't implement it was that I didn't have time to implement the
> color mapping.
> Not trivial if one wants to mimic the artifacts, etc.
I'm finding that out :-)
> Wanted to do it later but had too much real work to do.
I hate when that happens,
Charlie