#retrocomptuing — Public Fediverse posts

Il VDC del C128 è una cosa strana. E' un clone Commodore delle schede CGA per PC, con una sua memoria interna che può usare solo il VDC perché la macchina non "la vede" (una "memoria d'ombra"), e che può essere espansa fino a 64k in totale con i kit appropriati. Espanso al limite, il VDC può a risoluzioni folli per questa fascia di macchine, fino a 800x600 monocromatico in certe demo.

@computer @giochi

https://www.youtube.com/watch?v=X95wK7FS5NY

#c128 #retrocomptuing #commodore #videogiochi #retrocomputer

So, it looks like I can fit the “core system” (CPU, RAM, ROM, address decoding) on one standard size #Z50Bus card.

#retrocomptuing #electronics

There’s also an #RCBus version

https://www.tindie.com/products/tindiescx/sc701-rcbus-80pin-backplane-kit/

#retrocomptuing #electronics

I like this one with built in power and reset

https://www.tindie.com/products/tindiescx/sc513-modular-backplane-kit-for-z50bus/

#Z50Bus #retrocomptuing #electronics

So, after looking at backplane kits on Tindie, I think one designed for the #Z50Bus will work. If I remove all the Z80 specific pins that don't have 6502 equivalents, that leave enough room for all my IO_SELECT signals.

#retrocomptuing #electronics

Picking this thread back up while I wait on my chili to simmer.

I’m considering buying an existing backplane kit like an #rc2014 and just using it for my own purposes (ignore the official pin outs).

Then I could build dev modules of my system and connect using that.

#retrocomptuing #electronics

I’m still prototyping component of this system (sound generation, mass storage etc), so I’m not ready for the final design.

My question is, what is the best interim design?

I could build modules that connect to a backplane that shares the main system bus.

I could build a partial single-board system with pin headers for the system bus.

Or is there a better way to approach this?

2/2

#retrocomptuing #electronics

I think I’m at the point where I would like to make a PCB out of my 6502 machine. It started life as the Ben Eater 6502 kit, but I’ve made several changes from the original design.

The end goal is to have a ~1980 era home computer form-factor. Everything on a single board inside the keyboard housing like an Apple II, Atari 800, or Commodore 64.

1/x

#retrocomptuing #electronics

Or maybe this one would be more super? #retrocomptuing #supercard #HyperCard

I just wrote an xmodem receiver routine for my homebrew 6502 computer. Now I’ll be able to test programs without having to pull the EEPROM every time.

#retrocomptuing

Achievement unlocked: I burned my finger grabbing an IC off the breadboard that was running hot.
#retrocomptuing

We’ll, I’m back on my #fpga video processor for my 6502 computer. Today, I’m adding color to my text mode. I have 3 bits per R/G/B, which makes for 9-bit color values. Not really ideal for an 8-bit computer.

I’m thinking of only using 2 bits for B, but to get consistent color mixing, I want to use the same resistor DAC for each color.

My plan now is to ignore the low bit except when both upper bits are set.

Does this make sense?
#retrocomptuing

Inspired by @vwestlife I thought it would be fun to try OS/5 on my Amstrad PPC640 with its mono LCD.

It does indeed work fine! Slow, as you'd expect on a V30! Great fun.

https://youtu.be/T4OG4FsLPTE

#retrocomptuing

Ok, first stupid mistake corrected: I forgot to wire VCC and GND to my new SRAM IC. 🤦🏻‍♂️

Still not working. More to go.

#retrocomptuing #electronics

Calling all #retrocomptuing #Apple #macOS enthusiasts - help needed for debugging Tetris Max on System 6 👀

https://www.bigmessowires.com/2023/07/28/tetris-max-2-9-1-and-macintosh-system-6-0-8-bugs/

(latest research is in the post comments, make sure to check those out)

I’m thinking about the memory layout for my 6502 system. I’m going to have at least 64K of RAM, which means bank-switching. My question is: is is more preferable to have many small banks or few large banks?

#retrocomptuing

Absolutely cannot wait for the demo of CRT7 from @AmicableAnimal to drop in 4 days

https://store.steampowered.com/app/2096780/CRT7/

Looks drop dead #retrocomptuing #gaming aesthetic gorgeous, with the care and attention to sound and puzzles I've come to love/expect from the creator of SOLAS 128 (which I also highly recommend! https://store.steampowered.com/app/1257850/SOLAS_128/)

You shouldn't want to use a huge instance like mastodon.social. Those instances are impossible to moderate properly, and have no central theme to build themselves around other than "we aren't Twitter", which is a fine thing in and of itself, but is not sufficient cause to build a community.

So when I say that "black twitter" needs to have their own instances, I am not suggesting segregation, I'm suggesting that they be in charge of their own rules, be fully empowered to protect themselves and each other, to build the community the way they want it. I certainly wouldn't use an instance that refused to federate to them, I value their voices -- but the fact is that what serves the interests of, say, #retrocomptuing, will not necessarily always be what serves the interests of some other topic that an instance might focus on, and that's just how Masto has to be.