From: Jeri Ellsworth (
Date: 2000-09-27 06:15:45

    I am having a hard time deciding where to plug this thing in.  I
actually started the project AS a super C64 on a chip or two.  Mostly my
design has been around VIC compatible registers on a much faster buss.  If I
hack this into a C64 then I'm stuck with that configuration(memory map) in
the S-C64.

    Any help people can give with the original VIC internals will be very

----- Original Message -----
From: Richard Atkinson <>
To: <>
Sent: Tuesday, September 26, 2000 8:43 PM
Subject: Re: VHDL

> Jeri,
> Very interesting project. I and several others talked about VIC-II
> reverse-engineering projects for several months and it comes up quite
> frequently on csc in the form of the "someone should do a c64 on a chip"
> thread. However, it was only in the past few weeks that I actually started
> on my VIC-II in Verilog project in earnest. My new job at
> had something to do with it... It's not really got to
> anything like the stage yours has, of course.
> Anyway, I'm interested in adding VIC-II compatibility to your design, but
> some fundamental decisions have to be made. Originally I proposed an FPGA
> with some pins that were plug-in replacements for the real VIC, but made
> no attempt to provide an analogue interface (of course). Instead, a 4 bit
> (or possibly 8 bit) digital output for the colour numbers at the current
> pixel (the extra 4 bits being for the line above which is relevant in a
> PAL emulation) was the plan. Then I thought about integrating a "RAMDAC"
> too, with some method of changing the default colour allocations in case
> the user didn't like them.
> What's your ultimate aim for your video chip project? Will it be a plug-in
> replacement for the VIC-II or a hybrid similar to mine or a second display
> like the one in the SID socket at the Expo? Leaving aside C64-on-a-chip
> concerns for now, I think the VIC-II is the first hurdle. PAL/NTSC and
> revision selection are easy enough to implement, hence I included them in
> my original spec. What I left open (although thinking about them for a
> while) were enhancements to the VIC-II; particularly a second memory
> interface for high speed video accesses (hires video modes etc) and the
> precise details of how the analogue video interface would work. I
> certainly had connection to an RGB 15kHz television-style monitor in mind,
> though. VGA was not in my original plan.
> Richard.
> -
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