Search found 794 matches

by Rasputin
Tue Aug 09, 2016 5:27 am
Forum: HELP!
Topic: AX-80 O.S. hacking co-op?
Replies: 89
Views: 21263

Re: AX-80 O.S. hacking co-op?

I can now decode tape dumps, so if anyone wants to develop a patch editor then I can give you a couple files to play with and the technical details / file format.
by Rasputin
Fri Aug 05, 2016 6:41 pm
Forum: HELP!
Topic: AX-80 O.S. hacking co-op?
Replies: 89
Views: 21263

Re: AX-80 O.S. hacking co-op?

Well... Frankenstein is at least twitching on the operating table in the laboratory of the mad scientist. I added SysEx out to the firmware and the good news is data transferred and it didn't (seem to) break the Tape/Save function. The bad news is that my h4x0r skills are not l337 enough because it ...
by Rasputin
Fri Aug 05, 2016 2:22 pm
Forum: HELP!
Topic: AX-80 O.S. hacking co-op?
Replies: 89
Views: 21263

Re: AX-80 O.S. hacking co-op?

Problem is the keyboard is 30 miles away. I assume I need the version letter of the CEM chips? How to pick the problem CEM IC? Either that or know your ROM version. If the EPROM has a letter "I" then you need version B chips and letter "K" for version C. If you know the date the AX80 was made you c...
by Rasputin
Thu Aug 04, 2016 6:17 pm
Forum: HELP!
Topic: AX-80 O.S. hacking co-op?
Replies: 89
Views: 21263

Re: AX-80 O.S. hacking co-op?

Amazing work on the CPU, by the way! Why, thank you :) Latest update on the project is that I've coded the SysEx out and it should only take about 25-30 bytes in practice. If SysEx in works to be the same then we're in under our mark. I'm having trouble finding ways to optimize and shave it down, b...
by Rasputin
Wed Aug 03, 2016 3:42 am
Forum: HELP!
Topic: AX-80 O.S. hacking co-op?
Replies: 89
Views: 21263

Re: AX-80 O.S. hacking co-op?

If IC1 is the problem and it's truly cooked (not just fed bad power, etc.) then you're pretty well sunk without another AX80 to cannibalize, at least so far as I know. It would be nigh impossible to replace the keyscan CPU. Main CPU would be a tremendous hassle too, but IC1? Forget it. Though this ...
by Rasputin
Wed Aug 03, 2016 1:29 am
Forum: HELP!
Topic: AX-80 O.S. hacking co-op?
Replies: 89
Views: 21263

Re: AX-80 O.S. hacking co-op?

Problem is keys with no sound. It is always 8 keys apart. Are you testing this by playing random things or are you always testing the keyboard chromatically? I ask because it would behave like that if one voice was out and you were just going up (or down) the keyboard one note at a time. If you pla...
by Rasputin
Mon Jul 25, 2016 7:32 pm
Forum: HELP!
Topic: AX-80 O.S. hacking co-op?
Replies: 89
Views: 21263

Re: AX-80 O.S. hacking co-op?

I have the majority of the code broken up in to general regions and am making lots of progress as far as identifying/documenting functions. Making slight progress on the memory address issue, but it's still the bugbear. By my estimate, there are about 74 bytes free to cram some new features into, as...
by Rasputin
Mon Jul 25, 2016 1:32 am
Forum: HELP!
Topic: AX-80 O.S. hacking co-op?
Replies: 89
Views: 21263

Re: AX-80 O.S. hacking co-op?

Still getting the story from Akai that details of the AX-80 OS are long lost/destroyed. Next plan is to create a board with a small microprocessor and a bunch of tri-state buffers that can halt the CPU in the synth and do a 'body snatcher' like invasion of the RAM, translate the patches into MIDI a...
by Rasputin
Sat Jul 23, 2016 9:04 am
Forum: HELP!
Topic: AX-80 O.S. hacking co-op?
Replies: 89
Views: 21263

Re: AX-80 O.S. hacking co-op?

Judging by what I've seen so far, it may be feasible to dump patches via MIDI. Sections of the code I can identify are a couple memory initialization routines (Internal RAM being one), port configuration, serial port configuration, interrupt masking configuration, and timer configuration. Other sect...
by Rasputin
Thu Jul 21, 2016 8:00 pm
Forum: HELP!
Topic: AX-80 O.S. hacking co-op?
Replies: 89
Views: 21263

Re: AX-80 O.S. hacking co-op?

Okay, that's interesting. Could make this whole shindig pretty tricky, but on the other hand, if they have different firmware revisions, then either they'd have to replace the CPU as well, or it just contains data that wouldn't need to change between revisions (interrupt vectors, lookup tables for ...
by Rasputin
Thu Jul 21, 2016 7:40 pm
Forum: HELP!
Topic: AX-80 O.S. hacking co-op?
Replies: 89
Views: 21263

Re: AX-80 O.S. hacking co-op?

Well friends, you can thank insomnia that I dumped the ROM earlier today :D Akai AX80 Revision K ROM in its 8KB glory: https://drive.google.com/file/d/0B44NKm9yPA1bWjVuMzlPYXdrN2M/view?usp=sharing Took a quick peek at it and I have to say that it's not structured that closely to what I anticipated. ...
by Rasputin
Thu Jul 21, 2016 8:20 am
Forum: HELP!
Topic: AX-80 O.S. hacking co-op?
Replies: 89
Views: 21263

Re: AX-80 O.S. hacking co-op?

Well, that depends on what the differences between the firmware versions were. Unless they were made to support, say, two board revisions that change the architecture in a meaningful way, you'd presumably just do the hack on the latest version and assume that anybody who's going to be applying it w...
by Rasputin
Thu Jul 21, 2016 6:56 am
Forum: HELP!
Topic: AX-80 O.S. hacking co-op?
Replies: 89
Views: 21263

Re: AX-80 O.S. hacking co-op?

If someone wants to make a dump of the ROM (IC4) I could at least poke around a little. I don't have the binary yet, but I plan on dumping the ROM by the end of the weekend. No promises. One (of the many) problems with the OS hack idea is that I believe there were three different versions of firmwa...
by Rasputin
Thu Jul 21, 2016 5:30 am
Forum: HELP!
Topic: AX-80 O.S. hacking co-op?
Replies: 89
Views: 21263

Re: AX-80 O.S. hacking co-op?

I have neither the time nor inclination to complete this project all by myself, but I have some experience with this CPU and also Tape Out formats. If anyone is currently working on or planning to tackle this idea then feel free to respond here and I will offer what help and direction I can. But be ...