Jump to content

A full-blown newb on the way to a POKEY synth


Recommended Posts

I've got a software version that basically let's you play notes and push values into the registers manually - I'll post that here as soon as I gert back home next weekend.

are you home yet???  just joking!  i'm in the middle of a move so i won't be able to work on my box for another week or two.  just out of curiosity, can this "POKEY app" support two POKEY modules from one core?  i've built two modules so far but was planning on just building one core and connecting them the same way you would connect the two SID modules...  would that work?  thanks nILS!

Link to comment
Share on other sites

  • Replies 149
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Posted Images

Just got home yesterday ;-) To simplify things, please contact me via skype or ICQ. Dual-pokey support is on the wishlist and planned for, it's not in any way working yet though.

no prob.  i'll need to setup an ICQ or skype account but i won't be able to focus on this for another week or so...  i'm really excited.  i've been messing with RMT to get my fix until i can get my POKEY modules working. ;D  in ICQ, do i just click the "flower" under your name to get your account?  thanks a lot nILS!

Link to comment
Share on other sites

  • 2 weeks later...

Seeing on mikesarcade.com that Pokey is the sound chip on my old favorite, Tempest, I bought a pair of sealed BallBlazer carts through eBay for about $15.00, still a touch less overall than ordering from Mike's, etc. Well...they're soldered in! Not too surprising as they were after durability... My good advice is to just order from Mike's or similar and get them loose, NOS...

I can't wait to add that classic "MONG" tone to my rig  ;D

"Somebody get this duck away from me!" -Strongbad

Link to comment
Share on other sites

Hang in there, people :-) This is  taking me forever, I know, it's just that like most of you guys I don't have an infinty amount of time or money... Be patient, offer help, we'll get there ;D

Link to comment
Share on other sites

@ nILS.  i'm going to be contacting you through ICQ soon.  i just got internet in my new place and i just need to get a hold of a core and PIC etc... i'm going to try and help you as much as i can! ;D  talk to you soon!

Link to comment
Share on other sites

I'm not sure how exactly sound is output from the POKEY, but....

if it goes to a DAC, then you can buffer that, and read it asynchronously from a DAC, to change the pitch. no more problems with exact pitch.

then, a single pokey chip can be used as a four-voice chip.

if it gets output directly, maybe you can reclock the POKEY to change the pitch of the output? good idea?

if the pokey can be reclocked, you can couple it with a simple uC which would run at the same frequency as the pokey (especially when it's being reclocked. then you could have a sram buffer for the control info that gets written to by the 'outside' logic, and have the pokey-glue-uC reading from that sram and sending to the pokey itself.

then, the single pokey chip can be used as a 2/3/4 osc voice. as i understand pokey chips aren't too difficult to find - so this option is cooler imo :) 4 pokey oscillators are something!

hell, you could do ringmod, or maybe even simple FM between them? :)



Link to comment
Share on other sites

  • 3 weeks later...

edit: Latest schem is attached so you actually know what to build :-)

Shit!  i didn't even notice the new schematics until just now!  is the amplifier circuit from the audio out pin the only thing changed from v.0.3 schematics???  i hope so!  well... i've got some de-soldering to do.

Link to comment
Share on other sites

  • 2 months later...

Yes. Boards are being made, my pokey has most likely gone over the Jordan and I need to get a new one (anyone wanna donate one?) some minor testing routines have been implemented.

Everything is moving along... Slowly.

I think I might have a spare (ie, I have two total) in the batch I ordered a few years back.  Let me take a look for it.  Whereabouts would I be shipping to?

Link to comment
Share on other sites

Hmmm I had an idea.  So since the POKEY can accept pots and keyboard, would it be possible to build in a keyboard, and pots for parameter tweaking.  Then this would also solve my midi keyboard issue too! :P  I'm very uneducated so I don't know if it would work.  Thoughts?

the problem with that is this:

POKEY register table

16 pokey registers - $D200–$D20F

Register Write                                       Read

           Name         Description              Name    Description

$D200 AUDF1 channel 1 frequency   POT0 potentiometer 0

$D201 AUDC1 channel 1 generator   POT1 potentiometer 1

$D202 AUDF2 channel 2 frequency   POT2 potentiometer 2

$D203 AUDC2 channel 2 generator   POT3 potentiometer 3

$D204 AUDF3 channel 3 frequency   POT4 potentiometer 4

$D205 AUDC3 channel 3 generator   POT5 potentiometer 5

$D206 AUDF4 channel 4 frequency   POT6 potentiometer 6

$D207 AUDC4 channel 4 generator   POT7 potentiometer 7

$D208 AUDCTL control over audio channels POTSTAT read of all 8 potentiometers port lines

$D209 STIMER timer start KBCODE last pressed key code

$D20A SKRES serial port status reset RANDOM random number generator value

$D20B POTGO start port scanning sequence


$D20D SEROUT serial port output register SERIN serial port input register

$D20E IRQEN IRQ interrupts activation IRQSTAT IRQ interrupts status

$D20F SKCTL control over serial port SKSTAT serial port status

the same bit registers used for audio are also used for the potentiometers... i.e.  can't use both at the same time but possibly one after the other....  either way, there would have to be a processor that translated all this, including the keyboard (qwerty not musical) key presses, running along side the micro controller already in place with the MIOS app for the handling of the POKEY.  basically, if you want to go the route you are speaking of, you might as well get and atari 8 bit computer and a tracker...  sorry to be a downer.  :'(

[edit] for poor chart alignment. ;D

Link to comment
Share on other sites

well you didn't burst my bubble but I think if you wanted to take an extra amount of time for not much you could do the audio and key/pot with multiple pokeys, and with the one after the other you could tweak a parameter and then set it, and with the qwerty I saw somewhere a guy took the circuit board and fitted musical keys but it still probably is a whole lotta work for a whole lotta nothing! ::)

oh and a quick unrelated question, has somebody made a midibox 64 keyboard?  I think it would be fun to incorporate those into a lot of midibox synths!

and NILS did you say the only way to edit parameters on this thing is with switches (for the shift registers)?

Link to comment
Share on other sites

well you didn't burst my bubble

In that case I will: No pots.

oh and a quick unrelated question, has somebody made a midibox 64 keyboard?

Yes, that has been done, and no it doesn't belong in this thread at all.

and NILS did you say the only way to edit parameters on this thing is with switches (for the shift registers)?

Yeah, you'll have to punch all the binary numbers into the chip in real-time with push-switches ::)

read: No.

edit: Since I don't really feel like shutting down other people's ideas completely: If you really have your heart set on using the Pot-inputs of the pokey, you're more than welcome to implement it in hardware and software. I personally don't see the point as pots and buttons are handled by DINs/AINs so nicely that hacking that into the pokey - which *will* lead to a *lot* of extra work - is extremely pointless.

Link to comment
Share on other sites

  • 3 weeks later...

Hello everyone. I came across this thread while reading about SID programming and thought I might be able to contribute. I've been developing a voltage-controlled synth module that uses the POKEY. Audio demos are on my website at www.skrasoft.com

The four channels are divided into one 8-bit, one 16-bit, and one audio input. The goal was the widest range of sounds possible. It is almost complete, I am just making design changes to tame noise on CV inputs.

I realize my design doesn't fit into the midibox format, but we're both doing musical control of a POKEY.  :)

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...