Search found 699 matches

by Kakemoms
Mon May 30, 2016 12:44 pm
Forum: Hardware and Tech
Topic: S-Video conversion possible as plug-and-play solution?
Replies: 87
Views: 79959

Re: S-Video conversion possible as plug-and-play solution?

Well, I finally got around to install it on a 1983 Vic-20 I bought from Italy that has WG C serial and a socket on the VIC chip. I also have another 1983 model without serial that doesn't have a socket.. quite strange. Both machines are PAL, but the WG C has a "thinner" VIC 20 on its logo....
by Kakemoms
Thu May 26, 2016 2:10 pm
Forum: Hardware and Tech
Topic: Making a 65C02 based unit
Replies: 46
Views: 9221

Re: Making a 65C02 based unit

I managed to run a short program on the 65C02 that modifies the memory while another program runs in the Vic-20 and plots that memory location to the screen. Unfortunately it stops within a few cycles, so not very stable at the moment.. Anyway, it seems to work! Which is a nice feeling :) Its appare...
by Kakemoms
Thu May 26, 2016 6:58 am
Forum: Hardware and Tech
Topic: Making a 65C02 based unit
Replies: 46
Views: 9221

Re: Making a 65C02 based unit

eslapion wrote:@kakemoms
Did you check your claims about timing with a logic analyzer or scope?

Doesn't seem right at all to me.
Yea i did. It looks like I have to rethink the WE logic for the SRAM (see above).
by Kakemoms
Thu May 26, 2016 6:58 am
Forum: Hardware and Tech
Topic: Making a 65C02 based unit
Replies: 46
Views: 9221

Re: Making a 65C02 based unit

I am not sure I understand. As far as I know, all 65(C)02 variants write during CLK2=hi, and they read data essentially on the falling edge of CLK2 (so, at the end of the cycle). I think there is something else going on. You can drop a 65C02 into a 4040 drive, and it will work find, and that drive ...
by Kakemoms
Tue May 24, 2016 1:21 pm
Forum: Hardware and Tech
Topic: Making a 65C02 based unit
Replies: 46
Views: 9221

Re: Making a 65C02 based unit

Short update: I finally managed to track down two problems that affected the design. It took a 16ch logical analyzer (a cheap one from china) and some time to find that the timing has several problems: For the NMOS 6502 in Vic-20 you only read or write data in the clk2 being high. The address reques...
by Kakemoms
Fri May 20, 2016 1:54 am
Forum: Programming
Topic: Ultimem boot and file manager
Replies: 4
Views: 1758

Re: Ultimem boot and file manager

This is very impressive! I am able to get 37K into my Vic (by including IO2/3) and it might be possible to sequeeze some extra bytes out around the VIA registers as well. But with paging and Ultimem you probably don't need to bother with that.. How much is the bitmap, gfx routines and overhead when ...
by Kakemoms
Mon May 16, 2016 1:12 am
Forum: Collecting and History
Topic: Vic-20 PET on ebay
Replies: 1
Views: 1055

Vic-20 PET on ebay

Just wanted to hint of a Vic-20 with PET keyboard on ebay right now.
by Kakemoms
Sat May 14, 2016 9:09 am
Forum: Other Systems
Topic: Amiga 1000 keyboard
Replies: 6
Views: 1941

Amiga 1000 keyboard

I just bought an Amiga 1000 without keyboard. The keyboards seems to be hard to come by for some reason so I am just wondering if anyone here had an original A1000 keyboard laying around that they don't need. Even something with a few keys missing would be ok.
by Kakemoms
Tue May 10, 2016 6:17 am
Forum: Hardware and Tech
Topic: 6562/6563 datasheet
Replies: 33
Views: 2968

Re: 6562/6563 datasheet

Multiplexing is a terminology that has nothing to do with RAM and was used even before anyone made DRAM. In fact, the first DRAM didn´t even use multiplexing. If you had read the links I sent, you would have known that: "Time-division multiplexing is used primarily for digital signals, but may ...
by Kakemoms
Tue May 10, 2016 2:35 am
Forum: Hardware and Tech
Topic: FPGA replacement for VIC I chip?
Replies: 217
Views: 24305

Re: FPGA replacement for VIC I chip?

I've just discovered these: http://www.google.com/patents/US4551682 http://www.google.com/patents/US4561659 Judging by the dates and the content (e.g. sprites), they appear to be more applicable to the VIC-II chip. But I'm really hoping there will be a few nuggets in there that apply to the VIC-I c...
by Kakemoms
Tue May 10, 2016 1:56 am
Forum: Hardware and Tech
Topic: 6562/6563 datasheet
Replies: 33
Views: 2968

Re: 6562/6563 datasheet

The Vic-20 uses SRAM and has a time-division-multiplexing between the 6502 and 6561. So yes, it has multiplexing. Say what??? The 6502 uses one half of every clock cycle while the 6560/61 uses the other half. This is not multiplexing, unless you desperately want to confuse everyone. No I don't conf...
by Kakemoms
Mon May 09, 2016 11:38 am
Forum: Hardware and Tech
Topic: 6562/6563 datasheet
Replies: 33
Views: 2968

Re: 6562/6563 datasheet

The Vic-20 uses SRAM and has a time-division-multiplexing between the 6502 and 6561. So yes, it has multiplexing. DRAM multiplexing is only to reduce the number of address lines by alernating the LSB and MSB. You still need to do time-division multiplexing to allow two IC's to access it, but differe...
by Kakemoms
Mon May 09, 2016 10:15 am
Forum: Hardware and Tech
Topic: Making a 65C02 based unit
Replies: 46
Views: 9221

Re: Making a 65C02 based unit

Another update: I changed some components, added AND and XOR chips and revised the logic, so now all memory works on the 6502 side. The 65C02 seems to be ok, but I may need to fix some more timing issues before I solder in a programmable oscillator (SOIC). Future fixes may include an assymetric clk2...
by Kakemoms
Sun May 08, 2016 4:00 pm
Forum: Hardware and Tech
Topic: 6562/6563 datasheet
Replies: 33
Views: 2968

Re: 6562/6563 datasheet

Every C64 can run Max cartridges in "Max" mode, so it would incur that they work the same way when this mode is enabled. As the first Max had 6566 video it is anyway interesting as for the evolution of the Vic-I chip?
by Kakemoms
Sun May 08, 2016 8:38 am
Forum: Buy, Sell, and Trade
Topic: Commodore Max
Replies: 3
Views: 1249

Re: Commodore Max

Price of a MAX has gone slowly up over the years (I paid about $400 for my complete one more than a decade ago) but no way $1500 now. Just for reference, I paid 625 Euros for my complete Vic-1001, also a decade ago. I think the Max is overpriced. I mean, its as common as a Commodore 116 (about 5000...