Search found 229 matches

by JonBrawn
Sat Jun 01, 2024 2:43 pm
Forum: Hardware and Tech
Topic: Kung Fu Flash - like device?
Replies: 0
Views: 1

Kung Fu Flash - like device?

Wotcha! So I asked about banked EEPROMs, and they don't seem to really exist in a form in which I could use them. So how about something like the Kung Fu Flash, which pretends to be a floppy drive by taking over some of the vectors from the KERNAL, pulling data off a microSD card super fast, and rea...
by JonBrawn
Sat Jun 01, 2024 12:08 am
Forum: Hardware and Tech
Topic: Victor Progress
Replies: 2
Views: 83

Victor Progress

For those of you with pachydermal memories, you may recall that I was using an FPGA to develop a replacement for the 6560/61 VIC chip. This project stalled for quite a while because of ill health and another project I wanted to finish. I'm now restarting work on Victor, and the next task is to creat...
by JonBrawn
Fri May 31, 2024 11:49 pm
Forum: Hardware and Tech
Topic: Paged EEPROM
Replies: 5
Views: 104

Re: Paged EEPROM

Are these available pre-built and firmware flashed?
by JonBrawn
Fri May 31, 2024 11:17 pm
Forum: General Topics
Topic: Victor at VCFSW (June 14-16th 2024)
Replies: 0
Views: 70

Victor at VCFSW (June 14-16th 2024)

If you are in Dallas for Vintage Computer Festival South West this year, I'll be demonstrating Victor.

(mod: see www.vcfsw.org)
by JonBrawn
Fri May 31, 2024 11:16 pm
Forum: Hardware and Tech
Topic: Paged EEPROM
Replies: 5
Views: 104

Paged EEPROM

I don't suppose there exists an expansion cartridge that is one (or preferably more) largest EEPROMs setup to map into the $A000-$AFFF and $B000-$BFFF spaces, but with banking registers so you can select which block of EEPROM appears in each of the ranges?
by JonBrawn
Fri May 31, 2024 11:11 pm
Forum: Hardware and Tech
Topic: Audio to expansion port
Replies: 5
Views: 249

Re: Audio to expansion port

You could design a cartridge with a SID in it and feed the output back using pin Y so that it comes out through the regular AV DIN connector on the back of the machine.
by JonBrawn
Wed Feb 14, 2024 4:16 pm
Forum: Programming
Topic: Playing better notes
Replies: 1
Views: 1585

Playing better notes

I read, somewhere, of a program that toggles between two values in a sound register to produce frequencies closer to real notes - do any of you know what I'm talking about and where I could get it from?
by JonBrawn
Tue Feb 13, 2024 5:49 pm
Forum: Hardware and Tech
Topic: Powering a C64 (or VIC-20) with a USB Power Bank
Replies: 9
Views: 5251

Re: Powering a C64 (or VIC-20) with a USB Power Bank

Something's not firing on all cylinders - Denial has just emailed me to notify me that Mike made that post!
by JonBrawn
Sat Feb 03, 2024 8:35 pm
Forum: Hardware and Tech
Topic: Victor 6560 Replacement - Added graphics ops, just for fun
Replies: 5
Views: 2036

Re: Victor 6560 Replacement - Added graphics ops, just for fun

...you might want to take a sharp look at my ellipse routine (snippet taken from one of my example programs for MINIGRAFIK): If you're following in my footsteps, you might need to know that the range of some of those variables is somewhat larger than you'd imagine: For a resolution of 172x184, e(-5...
by JonBrawn
Wed Jan 24, 2024 10:10 pm
Forum: Hardware and Tech
Topic: Victor 6560 Replacement - Added graphics ops, just for fun
Replies: 5
Views: 2036

Re: Victor 6560 Replacement - Added graphics ops, just for fun

I'm assuming (MX,MY) is the center point and that A and B are the major and minor radii? What you have here looks very similar to the code I have in Victor, give or take the ellipsy bits. I'll stare at this for a while and see if I can get it going. Thanks! Rounded rectangles would be neat, but that...
by JonBrawn
Tue Jan 23, 2024 6:30 pm
Forum: Hardware and Tech
Topic: Victor 6560 Replacement - Added graphics ops, just for fun
Replies: 5
Views: 2036

Victor 6560 Replacement - Added graphics ops, just for fun

I've not been working on Victor, the 6560/61 replacement FPGA, for a little while due to health issues. To break myself back into working on it I implemented some graphics primitives, just for fun. Drawing points, lines, boxes, rectangles, circles and filled circles: https://www.youtube.com/watch?v=...
by JonBrawn
Sun Jan 07, 2024 10:40 am
Forum: Hardware and Tech
Topic: Vic 20 Rev D, low voltage across the board, black screen
Replies: 16
Views: 8051

Re: Vic 20 Rev D, low voltage across the board, black screen

It's worth noting that 74LS series chips aren't as plentiful as they used to be, and unscrupulous dealers will sell you re-marked 74HC chips (or is it HCT?), claiming them to be LS. They'll often work for the job in hand, but you need the real thing occasionally, especially in crystal oscillator clo...
by JonBrawn
Sun Jan 07, 2024 10:15 am
Forum: Programming
Topic: Pixel, pixel, on the wall - who's the squarest of them all?
Replies: 3
Views: 3773

Pixel, pixel, on the wall - who's the squarest of them all?

Wotcha!

When you are writing games or other graphics routines for your VIC-20 you'll sometimes need to compensate for the pixels being rectangular rather than square. My question is:

What aspect ratio do you assume for pixels in your code?