27 Feb
2006
27 Feb
'06
2:58 a.m.
In message <m1FDSKS-000IyVC at p850ug1>
ard at p850ug1.demon.co.uk (Tony Duell) wrote:
So not fast enough to get 2fps on an Alife simulator. Drat.
Looks like I need to make my homebrew LCD controller 6502-bus-compatible
then. 480x256 monochrome - it's not much, but it should work pretty well. It
would be even nicer if I could get Hitachi to give me a copy of the specsheet
for the SP21H002-Z1A display. I've been told it's a 640x200 RGB display with
a touchscreen, but nobody seems to have a specsheet and all the controller
chips are chip-on-glass. The sales guy at Hitachi can't even be bothered to
either return my calls or reply to the email I sent... natch.
I wonder how
fast I can refresh an 80x24 VT display over a 19200 Baud RS232
link...
Well, if you hae to re-write the entire screen each time :
19200, assuming 10 bits per character (start, 8 data, 1 stop) is 1920
characters/second. Your screen has 1920 characters. So one full screen
per second, maximum second. In fact the PERQ easily beat it -- the peak
speed, assuming all
you were doing was displaying things on the screen, was nearer 10 full
screens per second, and that's a full PERQ secreen, which displays
something like 80*66 characters.
Wow. Not bad. That said, the VRAM would have been memory-mapped, so I would
have expected a decent write speed anyway.
Thanks.
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