Search found 98 matches

by sjgray
Wed Jan 17, 2018 3:08 pm
Forum: Hardware and Tech
Topic: 40 80 column cards
Replies: 16
Views: 281

Re: 40 80 column cards

Steve, thanks for your interest in completing the project. I'm really the "buy a ready-to-use commercial product only" kind of guy, so I hope your work will inspire someone in bringing forth a 40/80 card for the 21st Century :) . That's totally fine. I'm actually the same way, since I don...
by sjgray
Wed Jan 17, 2018 11:47 am
Forum: Hardware and Tech
Topic: 40 80 column cards
Replies: 16
Views: 281

Re: 40 80 column cards

I have completed a preliminary design of the VIC-20 version of my VYMS64 cart. This includes V9958 Video with 64K VRAM, YM2413 Audio, 6551 ACIA RS-232, plus 32K RAM for main VIC memory. Schematics and info is available on my VYMS web page: http://www.6502.org/users/sjgray/projects/vyms64/index.html ...
by sjgray
Mon Jan 15, 2018 5:31 pm
Forum: Hardware and Tech
Topic: 40 80 column cards
Replies: 16
Views: 281

Re: 40 80 column cards

It looks lke Eslapion's ram expander uses one 32K chip and a single LS'08... Yes. The Ultimate Expander used a 62256 SRAM IC or equivalent and a 74LS08. Since the BLK 1,2,3 and 5 areas represent 8kBytes each, it is required to re-encode these signals for compatibility with a single 32kBytes memory ...
by sjgray
Mon Jan 15, 2018 1:01 pm
Forum: Hardware and Tech
Topic: 40 80 column cards
Replies: 16
Views: 281

Re: 40 80 column cards

Well, I've sorted out the cartridge edge connector footprint. Just need to add the RAM. Anyone know of schematics for a simple 1-ram-chip circuit? I think I have room for a skinny-dip ram and one more chip. It looks lke Eslapion's ram expander uses one 32K chip and a single LS'08... The PCB is alrea...
by sjgray
Sat Jan 13, 2018 6:04 pm
Forum: Hardware and Tech
Topic: 40 80 column cards
Replies: 16
Views: 281

Re: 40 80 column cards

A quick look on ebay shows plenty of V9958 chips available in quantity. In the past I've purchased parts from G&C and Polida2008 without any problems. Also funkward-tech can put together the V9958 with whatever supports components you need for a fairly reasonable price (look for "yamaha v99...
by sjgray
Fri Jan 12, 2018 8:23 pm
Forum: Hardware and Tech
Topic: 40 80 column cards
Replies: 16
Views: 281

Re: 40 80 column cards

I started an 80-column cartridge for the C64 here: http://www.6502.org/users/sjgray/projects/vyms64/index.html This cartridge uses a Yamaha video chip like used in the MSX2 computers, a Yamaha sound chip, and a Link-232 inspired RS-232 circuit. I designed this to learn about the Yamaha V9958 video c...
by sjgray
Mon Nov 13, 2017 3:33 pm
Forum: Hardware and Tech
Topic: VIC-2000 Expander. Modern Power Using Retro Parts!
Replies: 132
Views: 3717

Re: VIC-2000 Expander. Modern Power Using Retro Parts!

Brad, I have a project to generate 256 colours on the PET. While looking into DACs I saw this on your page: http://www.lucidscience.com/projects/VGA%20Video%20Generator/3.jpg I wonder why you use 6 resistors and 6 diodes for Intensity. Could you not just use 2 resistors joined, then split into 3 wit...
by sjgray
Mon Nov 13, 2017 11:25 am
Forum: Hardware and Tech
Topic: VIC-2000 Expander. Modern Power Using Retro Parts!
Replies: 132
Views: 3717

Re: VIC-2000 Expander. Modern Power Using Retro Parts!

Hey Brad, Have you considered demonstrating your stuff at a show? World of Commodore is coming up in December, in Toronto, and there are lots of Denial members coming to the show. I reserved two tables, but now it looks like I may not be able to use one. I bet people would like to see your stuff in ...
by sjgray
Mon Nov 06, 2017 10:55 am
Forum: Hardware and Tech
Topic: VIC-2000 Expander. Modern Power Using Retro Parts!
Replies: 132
Views: 3717

Re: VIC-2000 Expander. Modern Power Using Retro Parts!

Had an hour free this evening, and decided to try my crazy "Remote 6560" idea. I will admit that I only gave this a 75% chance of working. Started by soldering a socket to the ZIF socked so I could attach 40 wires. The idea was that the 6560 could live outside the VIC-20 and at the same t...
by sjgray
Tue Jul 11, 2017 11:54 am
Forum: General Topics
Topic: Additional Sound Chip Suggestions...
Replies: 16
Views: 511

Re: Additional Sound Chip Suggestions...

I love chip tunes. I know the SID is the big king in these parts (and for good reason) but that doesn't stop me from loving other sound chips like the AY-3-8910 and the SN76489. I also love being "period accurate" as much as I can. Meaning, a 64 voice polyphony sound system on a VIC-20 wo...
by sjgray
Sun Apr 23, 2017 8:37 am
Forum: Programming
Topic: Updated BASIC and KERNAL disassembly
Replies: 28
Views: 1991

Re: Updated BASIC and KERNAL disassembly

srowe wrote:
sjgray wrote:Here's another version with combined VIC/64 source:


This is very useful for comparing VIC vs C64 code. Any ideas which C64 ROM version this is?

Simon


It's version 3 as seen at line 17283.

Steve
by sjgray
Sat Apr 22, 2017 3:55 pm
Forum: Programming
Topic: Updated BASIC and KERNAL disassembly
Replies: 28
Views: 1991

Re: Updated BASIC and KERNAL disassembly

Here's another version with combined VIC/64 source:

https://github.com/sjgray/cbm-edit-rom/ ... rtKirk.asm

My site, but contributed by Edilbert. Included in one of my github projects.

Steve
by sjgray
Mon Mar 27, 2017 12:50 pm
Forum: General Topics
Topic: What is this adapter for?
Replies: 13
Views: 799

Re: What is this adapter for?

tokra wrote:I think it is supposed to work like this project:

http://www.go4retro.com/projects/converter/

However, as far as I can see, Jim never finished this one.


Actually, Jim had a few of these at a WOC show a few years back. I was able to pick one up.

Steve
by sjgray
Mon Feb 27, 2017 5:18 pm
Forum: Programming
Topic: Maxi-/Uber-Edit
Replies: 35
Views: 1991

Re: Maxi-/Uber-Edit

Steve, In short: this tool is great as wedge, not so as KERNAL patch. A program that uses this tool needs to be fully aware of it anyway. In principle, it gains its merits just like any of the known BASIC extensions - you invest some memory into the wedge to simplify some other aspects in your own ...
by sjgray
Mon Feb 27, 2017 1:58 pm
Forum: Programming
Topic: Maxi-/Uber-Edit
Replies: 35
Views: 1991

Re: Maxi-/Uber-Edit

I did a little investigating, and there is a potential problem putting this in ROM: The VIC-20 has a screen line-link table in zero page ($D9-$F1), that tracks when you print to the last character on the line, and if so updates the table to "link" the line to the next. That's how it knows ...

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