Mega65

I want this so bad, but it doesn't look like it'll ever get finished. Does anyone know of any existing alternatives?

mega65.org

Other urls found in this thread:

contiki.sourceforge.net/docs/2.6/index.html
zimmers.net/anonftp/pub/cbm/documents/projects/memory/vic20/32kB.html
en.wikipedia.org/wiki/Lunix
personalpages.tds.net/~rcarlsen/cbm/vic20/vic20.txt
mainbyte.com/vic20/manuals.html
jaycar.com.au/80w-desoldering-station/p/TS1513)
jaycar.com.au/metal-desolder-tool/p/TH1862
twitter.com/SFWRedditImages

Looks interesting, OP. Details?

Their git seems like its still getting updates, so I wouldn't throw the baby out with the bathwater just yet, but I must ask, why would anyone want something as niche as this and what is it's practical purpose?

Pretty sure this sort of thing isn't supposed to have a practical purpose.
What I wonder is why would anyone buy this instead of an actual C64 or Atari and have a large amount of software available, especially considering you can get one of those for $100 or less, and this thing will probably cost a small fortune.

Those are both over 30 years old

It's still 8-bit software we're talking about. There's no reason why you'd need modern hardware to use a thirty year old architecture. I genuinely don't know who this thing's for; retro coputer folks already have their favorite toys, and I don't imagine many coders are interested in 8-bit software that only they and 10 other people could run.

That being said, it would be cool to have one, and would probably spend some shekels on it, if only to dick around with and have fun coding for, if the price isn't much higher than buying an old-but-proven computer.

forgive my ignorance. can this thing do tcp/ip and shit? can 8bit technology connect to like muds and such run telnet? I want one.

If you want to build your own computer, there are plenty of kits out there already. I bought a Z80 kit last year. Maybe when I get around to it, I'll write some games for it and write them to the ROM.

The world of web design!

I doubt you can have TCP/IP stack in 64k RAM, but those machines were often used with analog modem to connect to a BBS or Unix shell account, and from there you could do Internet stuff.
Anyway the 8-bit systems are interesting in their own right, especially if you want to learn assembly language and make games or demos. Heck, they're even fun just for coding in BASIC (sometimes coupled with machine language inserted via POKE instructions) and playing games on.

Why is Holla Forums's /g/ so fucking ignorant?

github.com/jaseg/avr-uip

Someone hasn't heard of Contiki.

contiki.sourceforge.net/docs/2.6/index.html

OP here, yeah, at this point I may just get my old Vic 20 "geared up" with some modern peripherals and see what nerdiness I can do with it. First I have to grab an a/v cable, then a sd2iec adapter, then hopefully a wimodem once the creator re-releases it.

I mades me a 32kB RAM expansion for my VIC20 just yesterday...

Oh shit, that's pretty awesome.

And what exactly are you going to do with that in 64k, other than ping some hosts? Maybe telnet and IRC (with the most basic of clients). Possibly gopher. But modern web stuff won't work on such a machine, and neither will anything that requires crypto (ssh, https).

Nice.

Quads.

Mostly for fun, a lot of enthusiasts have bbs's running on their old machines, I might do the same. One guy wrote a news aggregator that'll connect to CBC news and display stories.

It's the design from zimmers.net/anonftp/pub/cbm/documents/projects/memory/vic20/32kB.html

Having a wire-wrap tool makes such a difference.. and I can easily add more projects and just wire them in-- I'm thinking another 6522 or 6521 PIA to give the 16 I/Os needed for a 8-bit IDE interface, and a 1kB EPROM area from the /IO3 for its bootstrap code ("sys40000").

As a 1980s kid, I feel it's more "because it could have". In the early 1990s, when TCP/IP became a thing, we had to finally drop our 8-bitters for the machines that had Trumpet Winsock and the like.

Hey I just remembered that this exists:
en.wikipedia.org/wiki/Lunix
So you can have your SLIP or PPP and all that jazz, on your C64.
I kinda wish I'd kept my own 8-bit computer throughout the 90's. Would have just used it as a terminal though. It had a nice 80 column display and green monitor that was nice and sharp (the one in pic looks fucked-up though). But I fell for the upgrade meme...

That screen, colors... My first computer was a VIC-20.

Did you eat a lot of porridge?

3583 BYTES FREE

:3

Update on my VIC20 hacking...

I've added a 2kB EPROM to the 32kB RAM expansion board-- this appears in the 1kB "/IO3" area from $9C00-$9FFF, with a switch on the EPROM's A10 address line to choose which 1kB half of the ROM is used (i.e: alternate versions of code).

In spite of the wiring mess, it worked first go!

And to try it out, I programmed my RS232 bootstrap protocol code into the EPROM. Now I can download to any area of RAM. (..and without having to worry about overwriting the bootloader).

Fuck that $200 'Vic 20 Penultimate cartridge' that's being shilled across retrocomputer social media. I made something else from spare parts.

Wish I knew how this shit works. Looks cool though, nice job

This is an 8-bit machine. A person who is truly interested should have the aptitude to wire together a Mega65 machine by themselves.

What gauge are those? Looks nice and hair thin, is it solid or braided? Where did you get it? Ever heard of wire wrapping?

"I have too many I/O interfaces" said no Computer ever.

I actually made it to the end of this hardware project without any fuck-ups. This last bit is adding a 3rd 6522 parallel interface IC to the system. The Vic 20 has two of them internally-- one is used for the keyboard, and the 2nd is the User/Serial/Peripheral ports. Adding a 3rd gives 16 GPIO pins, which is just enough for adding a bit-bang "8 bit" IDE HDD interface too...

...and it's a lot fucking easier to code for than Arduino!

(line 20: set all of Port A to be outputs, lines 30 and 50 frob the first GPIO line with the LED on it, if it wasn't obvious)

Photo #2 is a project from ~6 years ago where I got an IDE harddrive going on a 6502-based Synertek VIM1/SYM1 system from 1978--- so I have all the stuff already to get a HDD on a VIC 20...

nice hacks user

I should probably verify that everything works (..and in the process discovered that the 6522 in the previous photos had a dead pin on Port B-- fortunately I've got a replacement IC..)

...

bump

Oh, I'm about to save this thread from page 10...

I've now written much of the code for the "6522IDE" VIC20 interface, and it's now doing listings, loading, and saving files to/from the IDE interface.

It works!

Some more photos taken during development... (posted to twitter)

#1 The first time successfully reading a sector from a Compact Flash card-- sector #3 was filled with 0x03.. which appears as "C" in the VIC20's screen memory.

#2+#3 .. A goal for the project is to get 6522IDE working out of a 1kB EPROM, and without using any of the VIC20's main program memory (for buffers or etc.), while still making 'good' use of the gigantic-by-8-bitter-standards storage devices. That meant having to roll a filesystem from scratch, as FAT et.al. would've just been impossible. I came up with something, while only having to sacrifice the VIC's cassette buffer memory area-- a few programs stored machine code routines in that area... but it's a compromise, and will still let most programs, on expanded or unexpanded VICs work.

#1+#2 .. Loading files from IDE working!

#3 ..and saving to IDE working-- managed that tonight.

...and this is the plan for 6522IDE commands. It's looking like a few nice commands like Directory listing won't make it into the 1kB EPROM... but I think I've got a way to to keep the necessary features around in a usable way.

Photo#2 -- the next project.. That's an SD Card breakout Arduino 'shield' that has 3.3v-5v level converters. This could be wired up to the VIC's User port easily (a _lot_ easier than making a 6522IDE...) and it would just be a matter of replacing the IDE ReadSector/WriteSector code with SPI versions... Then it would a bit more useful and anyone else wanting to build their own VIC/C64/C128 storage project.

(Yes, there's dozens of off-the-eBay products out there like Penultimate Cartridge, IEC2SD just wait for your wallet... but some men just want an excuse to develop their own thing on these cute little computers in CURRENT_YEAR)

The point is that there aren't any more new ones being made and many are dead or dying. It's new manufacture, not "zombg upgraedz".

You absolute madman

Hey, uh
Since we're on the topic of the VIC-20 - I picked one up a while ago and it just spits out these garbled characters. I've already re-seated the socketed IC's. Is this indicative of a common issue, or am I going to have to do some more in-depth troubleshooting?

Are those solid yellow characters, or yellow and cyan? Either way, the memory being fetched by the VIC video chip is coming in as 0x0F ("O"=15 in PETSCII, colour 7=yellow, 15=yellow+cyan multicolour).

Could be the lower-4-bits SRAM chip (is only being read as 0b1111), the VIC chip, or the (RAM) address decoding (74LS138, 74LS139), at fault...

This could help as well: personalpages.tds.net/~rcarlsen/cbm/vic20/vic20.txt

Another trick is to check the temperature of ICs. If they're >50C/really-hot-to-the-touch only ~20 seconds after powering on, that's the likely culprit.

Hmm.. actually.. with the colour screen being configured (22x23 display, cyan border), we can know that the CPU and general RAM & ROM is okay.

Both the colour and screen contents are affected, so it's not a single 2114 fault.

There's the 4066 IC (UD1) and 74LS198(UC4) involved with the video chip's RAM fetching. Might be them.

Note: I'm using the VIC20"CR" ICs circuit and names. The schematics are on mainbyte.com/vic20/manuals.html

Try typing this blind on the keyboard:

POKE36878,15
POKE36876,200

If you get a tone sound, then it's more likely the 4066/LS198, and the Video (..and audio) chip is okay. Maybe.

I wasn't expecting such a helpful answer; thank you so much, user
The characters are solid yellow, occasionally if I turn it on they'll come in as solid cyan. I'll be sure to check the IC's you mentioned, and thank you for the links.

No tone sound, but I get a pop after entering the first poke command.
Probably the video chip then, right?

The first poke is the volume control, so a pop is good. Maybe try 36874 and 36875, the other tone channels. Poke values should be 128-255.

The VIC20 I'm doing all this stuff on at the moment was a rescue job as well, so this is all fresh in my head. You can see in this photo all the ICs I ended up testing/socketing/replacing (I think in the end just the left-most 6522 was bung).

Yeah, there's still a chance that the mussed-up data bus signals are happening inside the video chip, and then swapping in another 6560/6561 would be the thing to do. I expect you don't have one though :)

Still missing a tone, sadly.
Do you mind if I ask what kind of symptoms you were getting with the bad 6522? I doubt it's an issue with mine, but I'm just curious.


I've got an older VIC-20 that I can't test; I'll do some research and see if I can try a swap. Thanks again

The symptom was a 'white' (or rather bright-black) screen, and no signs of life from the CPU or other signal-making chips... so I socketed and test-swapped the CPU, the Video Chip, a 2kB RAM chip that got hot-to-touch, and when the /RESET line wasn't going high, the 74LS04 controlling that. With no better ideas, I resocketed the two 6522s, and it turned out one of them was faulty and always holding /RESET low.

When I got this VIC20 I had a bit of cash and went out and bought a full-on desoldering vacuum gun (jaycar.com.au/80w-desoldering-station/p/TS1513) and a circuit-board holder which made the job a lot easier with the ~200 pins all-up involved. In the following week I repaired 4 other VIC20 and C64s for a friend and it practically paid for itself :) .. Otherwise, just a regular (but good quality) soldering tool like jaycar.com.au/metal-desolder-tool/p/TH1862 is what you'd be up for if you're game to go beyond swapping socketed ICs. (Although a bit of skill with a soldering iron is needed so to not fuck up the PCB..)

more pics from the Resto..

First photo is the VIC20's motherboard before I started work.

Second is an early Made-in-Japan "9VAC" VIC20 (sadly, not a VIC-1001!) that I also repaired. You can see everything was already socketed-- it was a dead 6502 in this one I think. The Video chip was one of the earliest 6561s produced and the video output was really odd.

oops..

I bought a Commodore 64C awhile ago. I had an opportunity to get a Vic-20 instead, but decided to go for the 64 because I figured at the time I'd get more retro software support. Now I severely regret not going for the Vic-20 because a Commodore 64C from 1988 is barely "retro" to me and I wish I had gotten the Vic-20 for the whole "collectors" novelty aspect

Today's project was making an adapter for replacing the VIC's Kernal 8kB ROM (a 2364 chip) with a 27C64 EPROM (which has a slightly different pinout) so I can do customized ROM firmware-- to make 6522IDE easier to use & etc.

This is just buggering around.

Where's the Board Owner...

Late night hackings ... I've now got a cut-down verson of the 6522IDE code in a 1kB EPROM, making the VIC20 Harddrive system entirely 'self hosting' and available from a cold start, without having to bootstrap things like in

The largest VIC20 game I can find-- a 25kB version of Pooyan-- loads and starts in less than 3 seconds!

Fucking this.

Dear Blog,

Something I did with the SYM-1 harddrive 10 years ago was port FIG-FORTH to it, and used the 6522IDE to load and save FORTH's block files.

I certainly want to get this working on the VIC-20... however the standard editor in FIG-FORTH works on 64x16 'screens', and the VIC has 22x23. Also, from my experience coding in FORTH, source code needs at least a 32 column width to not look like an IOCCC entry ...so I'll need to write a basic text editor in machine code.

The VIC can have a maximum screen size of about 27x27, and there's no reason I can't make a 32x16 editor 'window' onto that. Possibly could make the FORTH run on large screen by default.

So this is a quick&dirty check to see what it would look like...