Denial

tokra wrote: ↑Thu Apr 13, 2023 3:36 pm I don't think you need an invitation, just register here:

You are correct - I saw the box for the invitation link and I ran away, as I didn't have an invitation link. Turns out you don't need that, just a bit of C64 knowledge.

If anyone out there in Denial Land could PM me an invitation to Forum64 so I can create an account, I'd be grateful.

Well, I thought I'd use the VICE Vic-20 colour palette for NTSC - except I don't understand the encoding in the structure. Take the two colours, Cyan and Green. First, there are some defines: #define ANGLE_RED 112.5f #define ANGLE_GRN -112.5f #define ANGLE_BLU 0.0f #define ANGLE_ORN -45.0f Then the ...

I have three 6560 chips - lovingly named "Red", "Green" and "Blue" - not because of any particular colour cast they have or anything like that, but because each one has a dot of that color stuck to it so I can identify them, for example, "Green" has a faulty r...

Thanks for replying. I'm using an original power supply, I've not had any obvious problems with it so far, but it does sound similar to one or two problems in threads I've found on this forum. I noticed they power supplies are very expensive to replace on eBay :( Is there any ways to tell if the po...

In theory all dark colours (2-8) should have roughly 2*L amplitude and all light colours (9-15) should have L amplitude, where L is the amplitude of the colour burst signal. But again this does not really work in practice. You're all going to hate my NTSC colour tables. Note that I am definitely no...

On the 6561 a line is not 64µs, rather 4*71/fsc, where fsc is the colour burst frequency. So slightly above 64µs. It's only out by 0.09%, which if it were independent of everything else wouldn't be an issue in the slightest, I'm sure. How you avoid the carrier being in lock with the horizontal line...

I'm looking into what I must do to support PAL on the 6561 FPGA. I'm going to be assuming PAL G / I parameters for the video are: 25 frames/second 50 fields/second 625 scan lines/frame 312.5 scan lines/field 288/576 visible lines per field/frame .576ms vert sync length 4.43361875 MHz colour subcarri...

I'd start by blaming the power supply. Are you using the original power supply from way back or a modern replacement?

If you are going to use a VIC-2020, be aware that you need real, genuine ICs for the 74 series logic, not random re-labelled knock-offs, and of the right family (e.g. if the parts list calls for LS then do not try HCT etc.) - his timing is very tight, and "only the best will do".

Also check with JLCPCB - they may be cheaper.

This product bought through Amazon worked for me without interference - make sure you give it a good ground connection. This is either 110 or 240V compatible: https://www.amazon.com/gp/product/B005T6UJBU/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 And this is the 9V AC transformer I used ***...

Nice video. Thanks. Looking forward to future episodes... I should have made a video about the board I've been working on to interface with the new FPGA development board I'm switching to. It would involve such epic scenes as "why are their connectors numbered backwards? There is no physical w...

The VIC (6560/6561) in fact has sepearate luma resistors for each colour, see for example this thread (partly in German) https://www.forum64.de/index.php?thread/110862-helligkeiten-der-c64-pal-palette-zum-100-mal/&postID=1699320#post1699320 I guess in the world that is FPGAs, I can say, "f...

History and technical info about what I've done so far: https://www.youtube.com/watch?v=fZqIlUJzN74