From: Marko Mäkelä (marko.makela_at_hut.fi)
Date: 2002-06-14 20:47:19
Andre Fachat wrote:
> do you also think that it is not possible to write "decent" video
> code on a 6545?
No, quite the contrary: a couple of weeks ago, I said in a Finnish news
group that a decent PET demo needs to be written. The fact that there
are no programmable characters makes things more challenging, but there
sure is a way to write fully synchronized raster interrupts.
> Well, depends on the definition of "decent", but
> I did some cycle-exact timing with the 6545 in the PET although
> it does not have a register to read (besides light pen which I
> do not use...) ;-))
It indeed has a readable "register": the IRQ output. The ULA in the
Tangerine Oric-1 doesn't have even that; it just reads stuff from memory
and is completely unobservable by the processor. Well, unless you used
open address space (the Oric equivalent of the C64 $de00-$dfff) to track
the video accesses.
> http://www.6502.org/users/andre/petindex/crtctest/pet/index.html
I see only screen shots there, but no links to the test programs. By
replacing the "index.html" in the URL with a guessed file name
"crtc1.a65", I got some source code, but I was unable to see precompiled
binaries. Could you mail those to me off the list? Preferrably before
Monday, since I won't take my 8032-SK with me to Adelaide.
Marko
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