Re: C2N232 on the Oric-1

From: Marko Mäkelä (
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.


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.


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