Synth-DIY Yahoo! Groups Archives

Thread

Demodulating and Encoding the Audio/Tape Data

2015-05-27 by compufart@...

Hi,

Does anyone know if the encoding scheme for the audio/"Tape" program or sequence data is publicly known? I recently pulled out my Poly800 for tinkering and modding, and I was thinking I might try to figure it out if nobody's done so already.

Thanks.

- Alex

Re: [korgpolyex] Demodulating and Encoding the Audio/Tape Data

2015-05-28 by Michael Hawkins

I can provide the tape assembler code to you if you would be interested in looking at it. But honestly, why?

/Mike

From: "compufart@... [korgpolyex]" <korgpolyex@yahoogroups.com>
To: korgpolyex@yahoogroups.com
Sent: Tuesday, May 26, 2015 8:54 PM
Subject: [korgpolyex] Demodulating and Encoding the Audio/Tape Data

Re: [korgpolyex] Demodulating and Encoding the Audio/Tape Data

2015-05-28 by compufart@...

Hi Mike,

I figured it might be good to have for a librarian or 'high-latency editor'. "Hey why not?"

I'm not putting too much time into this any time really soon, but if you want to share some of the source assembly, that would be helpful for sure.

- Alex

Re: [korgpolyex] Demodulating and Encoding the Audio/Tape Data

2015-05-29 by Michael Hawkins

Here is the tape disassembly as far as I took it. The main routines are labelled but the guts of each function is a mystery to me. Personally, I didn't see the point in trying to continue to use the tape function at all. So I didn't pursue disassembly any further than the basic entry point, functions and exit.

If anyone wants to pursue this I can provide a memory map of HW IO and memory.

But I would seriously suggest that any time spent on Poly would be better spent elsewhere. Just my two cents.

/Mike

From: "compufart@... [korgpolyex]" <korgpolyex@yahoogroups.com>
To: korgpolyex@yahoogroups.com
Sent: Thursday, May 28, 2015 12:23 AM
Subject: Re: [korgpolyex] Demodulating and Encoding the Audio/Tape Data

Re: [korgpolyex] Demodulating and Encoding the Audio/Tape Data [1 Attachment]

2015-05-29 by Gordonjcp

On Fri, May 29, 2015 at 12:56:04PM +0000, Michael Hawkins korgpolyex800@... [korgpolyex] wrote:

> Here is the tape disassembly as far as I took it. The main routines are labelled but the guts of each function is a mystery to me. Personally, I didn't see the point in trying to continue to use the tape function at all. So I didn't pursue disassembly any further than the basic entry point, functions and exit.
>
> If anyone wants to pursue this I can provide a memory map of HW IO and memory.
> But I would seriously suggest that any time spent on Poly would be better spent elsewhere. Just my two cents.
>

Tell you what I'd like to do is fix the patch corruption bug in the Poly 800 original firmware, and maybe graft in sysex patch dumping. I'd like to keep the rest of it the same though.

--
Gordonjcp MM0YEQ

Re: [korgpolyex] Demodulating and Encoding the Audio/Tape Data

2015-05-29 by Michael Hawkins

If I remember correctly, the patch corruption is caused by a stack overflow that pushes the stack up into the patch memory when MIDI comes into fast for Poly to process.

And sysex was left out of the Poly code because it can't fit with the keyboard and joystick code. So the EX-800 had sysex because it had no keyboard or joystick. I calculated fitting some sysex functions in to where the tape code was. But the tape code is actually quite small. So no luck there either. Bottom line is, there is no room.

And as you all know, I myself poured over the assembler years ago contemplating these problems. There is literally only 6 bytes unused out 8,192. It's a real shame that Korg chose to design the Poly with only an 8K ROM. Had they added just one socket for another 8K ROM, they could have dramatically improved the Poly and charged say $100 bucks for the upgrade.

So due to the space limitation, neither of your wishes can be granted.

/Mike

From: "Gordonjcp gordon@... [korgpolyex]" <korgpolyex@yahoogroups.com>
To: "Michael Hawkins korgpolyex800@... [korgpolyex]" <korgpolyex@yahoogroups.com>
Sent: Friday, May 29, 2015 8:58 AM
Subject: Re: [korgpolyex] Demodulating and Encoding the Audio/Tape Data

On Fri, May 29, 2015 at 12:56:04PM +0000, Michael Hawkins korgpolyex800@... [korgpolyex] wrote:
> Here is the tape disassembly as far as I took it. The main routines are labelled but the guts of each function is a mystery to me. Personally, I didn't see the point in trying to continue to use the tape function at all. So I didn't pursue disassembly any further than the basic entry point, functions and exit.
>
> If anyone wants to pursue this I can provide a memory map of HW IO and memory.
> But I would seriously suggest that any time spent on Poly would be better spent elsewhere. Just my two cents.
>

Tell you what I'd like to do is fix the patch corruption bug in the Poly 800 original firmware, and maybe graft in sysex patch dumping. I'd like to keep the rest of it the same though.

--
Gordonjcp MM0YEQ

Re: [korgpolyex] Demodulating and Encoding the Audio/Tape Data

2015-05-29 by Gordonjcp

On Fri, May 29, 2015 at 04:18:50PM +0000, Michael Hawkins korgpolyex800@... [korgpolyex] wrote:

> If I remember correctly, the patch corruption is caused by a stack overflow that pushes the stack up into the patch memory when MIDI comes into fast for Poly to process.
> And sysex was left out of the Poly code because it can't fit with the keyboard and joystick code. So the EX-800 had sysex because it had no keyboard or joystick. I calculated fitting some sysex functions in to where the tape code was. But the tape code is actually quite small. So no luck there either. Bottom line is, there is no room.
> And as you all know, I myself poured over the assembler years ago contemplating these problems. There is literally only 6 bytes unused out 8,192. It's a real shame that Korg chose to design the Poly with only an 8K ROM. Had they added just one socket for another 8K ROM, they could have dramatically improved the Poly and charged say $100 bucks for the upgrade.
>

What does the memory map look like? Is there room to just stick a 27128 in to replace the 2764? You'd likely need to do something clever with the address decoding but that's no biggie.

The Ensoniq Mirage has 16KB of OS RAM and 4KB of boot ROM - but there's a whopping 825 bytes unused in there! You could have all sorts of boot loader-y fun.

--
Gordonjcp MM0YEQ

Re: [korgpolyex] Demodulating and Encoding the Audio/Tape Data

2015-05-29 by Michael Hawkins

What does the memory map look like? Is there room to just stick a 27128 in to replace the 2764? You'd likely need to do something clever with the address decoding but that's no biggie.

That is what the HAWK does, except that if you're going to add a 27128 then you might as well as the HAWK which adds tons of additional space. So that is what I did. Did you ever buy the HAWK? I forget if you did.

The MDK kit from Korg was about the worst thing I've ever seen in a retrofit kit. It added only some of an additional 8K ROM and the work required to do the install was awful. And only just to add sysex. Wow, that was a bad retrofit kit.

/Mike

From: "Gordonjcp gordon@... [korgpolyex]" <korgpolyex@yahoogroups.com>
To: "Michael Hawkins korgpolyex800@... [korgpolyex]" <korgpolyex@yahoogroups.com>
Sent: Friday, May 29, 2015 1:11 PM
Subject: Re: [korgpolyex] Demodulating and Encoding the Audio/Tape Data

On Fri, May 29, 2015 at 04:18:50PM +0000, Michael Hawkins korgpolyex800@... [korgpolyex] wrote:
> If I remember correctly, the patch corruption is caused by a stack overflow that pushes the stack up into the patch memory when MIDI comes into fast for Poly to process.
> And sysex was left out of the Poly code because it can't fit with the keyboard and joystick code. So the EX-800 had sysex because it had no keyboard or joystick. I calculated fitting some sysex functions in to where the tape code was. But the tape code is actually quite small. So no luck there either. Bottom line is, there is no room.
> And as you all know, I myself poured over the assembler years ago contemplating these problems. There is literally only 6 bytes unused out 8,192. It's a real shame that Korg chose to design the Poly with only an 8K ROM. Had they added just one socket for another 8K ROM, they could have dramatically improved the Poly and charged say $100 bucks for the upgrade.
>

What does the memory map look like? Is there room to just stick a 27128 in to replace the 2764? You'd likely need to do something clever with the address decoding but that's no biggie.

The Ensoniq Mirage has 16KB of OS RAM and 4KB of boot ROM - but there's a whopping 825 bytes unused in there! You could have all sorts of boot loader-y fun.

--
Gordonjcp MM0YEQ

Re: [korgpolyex] Demodulating and Encoding the Audio/Tape Data

2015-05-30 by Gordonjcp

On Fri, May 29, 2015 at 08:56:02PM +0000, Michael Hawkins korgpolyex800@... [korgpolyex] wrote:

> What does the memory map look like? Is there room to just stick a 27128 in to replace the 2764? You'd likely need to do something clever with the address decoding but that's no biggie.
> That is what the HAWK does, except that if you're going to add a 27128 then you might as well as the HAWK which adds tons of additional space. So that is what I did. Did you ever buy the HAWK? I forget if you did.

I haven't. I'm almost ashamed to say my Poly-800 is still sitting in a box with half the keypad not working, having discovered it's one of the IO latches that's failed, and I've done exactly shit all with it for about three years. Once I get a few more projects off the bench I'll dig it out again.

Maybe I'll just stick a 27128 with an EX ROM in one half and a Poly ROM in the other half, and add a toggle switch to jump between them when I want to use it as a keyboard and when I want to use it with MIDI.

I'd like to get a Hawk kit at some point, but again - too many projects!

> The MDK kit from Korg was about the worst thing I've ever seen in a retrofit kit. It added only some of an additional 8K ROM and the work required to do the install was awful. And only just to add sysex. Wow, that was a bad retrofit kit.
>

What was the MDK kit?

--
Gordonjcp MM0YEQ

Re: [korgpolyex] Demodulating and Encoding the Audio/Tape Data

2015-05-30 by Michael Hawkins

The MDK kit was a ROM upgrade for the Poly. It gave the Poly the same sysex dump/receive as the EX-800.The kit was an abomination with dozens of tracks to cut and wires to patch in and a bunch of extra chips.

The 82C55 IO chip has 256 byte static RAM. What they did was shoe horn in another ROM.

See http://www.musictechnologiesgroup.com/files/Poly800-MDK.pdf

/Mike

From: "Gordonjcp gordon@... [korgpolyex]" <korgpolyex@yahoogroups.com>
To: "Michael Hawkins korgpolyex800@... [korgpolyex]" <korgpolyex@yahoogroups.com>
Sent: Saturday, May 30, 2015 5:42 AM
Subject: Re: [korgpolyex] Demodulating and Encoding the Audio/Tape Data

On Fri, May 29, 2015 at 08:56:02PM +0000, Michael Hawkins korgpolyex800@... [korgpolyex] wrote:
> What does the memory map look like? Is there room to just stick a 27128 in to replace the 2764? You'd likely need to do something clever with the address decoding but that's no biggie.
> That is what the HAWK does, except that if you're going to add a 27128 then you might as well as the HAWK which adds tons of additional space. So that is what I did. Did you ever buy the HAWK? I forget if you did.

I haven't. I'm almost ashamed to say my Poly-800 is still sitting in a box with half the keypad not working, having discovered it's one of the IO latches that's failed, and I've done exactly shit all with it for about three years. Once I get a few more projects off the bench I'll dig it out again.

Maybe I'll just stick a 27128 with an EX ROM in one half and a Poly ROM in the other half, and add a toggle switch to jump between them when I want to use it as a keyboard and when I want to use it with MIDI.

I'd like to get a Hawk kit at some point, but again - too many projects!

> The MDK kit from Korg was about the worst thing I've ever seen in a retrofit kit. It added only some of an additional 8K ROM and the work required to do the install was awful. And only just to add sysex. Wow, that was a bad retrofit kit.
>

What was the MDK kit?

--
Gordonjcp MM0YEQ