Quadro Pokey PCB (4x for TMC2)

[jmccorm]

NOTE: If I'm understanding this correctly (and I could very well be wrong -- I'm out of my depth here), it might suggest a cool additional feature, not actually part of the Major Havoc quad pokey but could be built onto a quad POKEY for 8-bit machines: a register which allows the audio channel from the 4th POKEY to replace/modify ground on the other channels?

 

This seems to be even more complicated. So, if someone with some audio electronics skills wants to chime in, here is a ZIP with the Major Havoc schematics (individual pages are in TIFF format). I've pre-digested this document, so to save you the time, here are the good parts:

 

Page 10A contains the Quad POKEY and the surrounding circuit. Find the large IC "QUAD CUSTOM IO" with the four audio outputs in the lower right of the chip. OUT1-3 are tied together and fed into a circuit, and OUT4 gets its own unique circuit. Then it appears that the output of those two circuits are tied together, and then all of it is processed yet again in a way that creates an AUD1 and AUD2 output that goes to the Atari Audio Regulator II board (as an audio amplifier). This is what mytekcontrols and shupac were talking about.

 

Page 02A picks up the AUD signals on the Atari Audio Regulator-II board, which is a standardized PCB (but with multiple revs which certain games will require). It creates speaker level outputs. Notice that the SPKRx-RETURN lines are tied to ground, which later a speaker would normally be connected to the SPKRx and SPKRx-RETURN lines.

 

Page 01B is where we take the SPKR* outputs from the AR-II board and actually feed them into the speakers. The oddity, as described earlier, is that normally, the SPKRx-RETURN lines from the AR-II board are used as audio ground and SPKRx have the audio signal. Instead, here, SPKR1 and SPKR2 are fed to the speakers (with no SPKRx-RETURN lines being used). So that's weird. And as mentioned, the speakers are also oddly wired. One speaker is connected directly to SPKR1 and SPKR2. Then there are two speakers which are connected in series before they are connected to SPKR1 and SPKR2. So this was the oddity on the other side of things that I was talking about.

 

All of this is so incredibly convoluted. Perhaps someone could help us make sense of what is going on here? Perhaps it was a way to select between sets of speakers? [specifically, a way to dynamically balance the output of 3 POKEYs between two channels rather than having two fixed audio channels with 2 unique POKEYs on each side?] Or is it as I originally imagined, a way to put a cool twist on the standard POKEY output without burning CPU? Both? Something entirely different? This one is odd, so some expertise would be appreciated.

 

Possibly worth further examination: how the audio was handled in the official Major Havoc to Tempest conversion PCB kit. The kit made no modification to the cabinet, so it used the more conventional speakers of the Tempest cabinet. (This is how I played Major Havoc. The kit had an authentic Major Havoc PCB, but it included a wiring harness that adapted it to the wiring of a Tempest game's cabinet. It effectively replaced the Tempest arcade PCB.)

Edited March 19, 2018 by jmccorm

[Matej]

Hey guys! Dont develop it. We have it almost done (95%).

[+mytek]

Hey guys! Dont develop it. We have it almost done (95%).

 

Matej I'm seeing individual Pokey chips in your layout. Where are people suppose to get 4 Pokeys in this day and age?

 

Best Electronics will only sell 1 maybe 2 (if you beg) per purchase, and his stock is dwindling fast. I really think it's time to do this via FPGA, and save what Pokeys are left for stock A8's and stereo boards. And it looks like the FPGA solution for quad Pokeys is getting ever closer to reality, just need to integrate the standard SIO, keyboard, and paddle functions to make it complete.

[Matej]

OK so we will make quadpokey for musicians (they love real chips) and you for gamers/users/arcade fans.Thats OK...

I have 20x pokey at home.But yes I am fanatic...FPGA is very good.There are also companies which can make from fpga normal asic chips.So can be interesting for future!!!

[+mytek]

OK so we will make quadpokey for musicians (they love real chips) and you for gamers/users/arcade fans.Thats OK...

I have 20x pokey at home.But yes I am fanatic...FPGA is very good.There are also companies which can make from fpga normal asic chips.So can be interesting for future!!!

 

i love real chips as well . But sometimes due to limited availability you need to substitute newer technology. Do you have a picture of one of your new boards?

[Matej]

Not finished.Developer is playing with smaller footprint and better mixing (gtia+pokeys).But will post first prototype here!

[Matej]

Guys can you than test TMC2 music composer by Jaskier??? There is 4x pokey support. Just few notes each channel... Also maybe release your core under some kind of friendly licence??? Maybe someone will add filters like on C64 are. In future... Thats cool on FPGA that can be upgradable.Maybe downloadable core on Ataribits.Or just well documented...For future.

[electrotrains]

I'm happy to contribute my sources for dual pokey on the MAX10 fpga if this helps get an FPGA version going. The code is largely foft's VHDL pokey implementation, with just a bit of glue code from me to get it working on an Atari cartridge.

 

I may have posted it earlier in the thread (Yes - I did!), but here is my original post about the project, along with some sample sound output from TMC.

https://atariage.com/forums/topic/250996-easter-holiday-project-dual-pokeys-on-an-ultimate-cart/

 

I didn't release the source originally, since it was just a quick hack/experiment, but if there is real desire for a dual/quad pokey implementation on an FPGA, then there's not actually much work to do... Add a few components to the PCB design for audio output, tweak the VHDL, and that's pretty much it. Happy to lend a hand if anyone is up for it...

 

Robin

[+mytek]

Instead of trying to replace the extended functionality of the stock Pokey in our A8's, why not retain it for what it's good for and do something more like this.

 

 

I reserved a pin on the header for perhaps a MONO mode select (would require some analog switches), or perhaps for an additional address line if you wanted to add even more cores.

 

Stock audio still exists on the monitor port.

[Matej]

I like it. How you will do stereo on monitor plug??? Extra pin??? Or have stereojack also in case and some kind of switch between monitor and jack or signal will be outputed to both at same time???

[Matej]

Also in far far future maybe few build in dsp effects will be nice.Like reverb,flanger,echo...Controlable via cpu.I mean effect for one core or choosen channel...

[Matej]

https://m.youtube.com/watch?v=ANxHyCAYGp0

[+mytek]

I like it. How you will do stereo on monitor plug??? Extra pin??? Or have stereojack also in case and some kind of switch between monitor and jack or signal will be outputed to both at same time???

In essence this is no different than the Simple Stereo board, and both left and right audio is brought out to a header for the user to terminate how ever they see fit (i.e., RCA jacks, or unused pin on monitor jack used for right channel). Since the A8's stock Pokey audio output goes through a buffer before connecting to the monitor jack, having that same audio output direct from the stock Pokey chip connected to the mixing circuit on this proposed 4-CH piggyback board allows simultaneous outputs with no switch required. However although it isn't shown, it might be nice to provide electronic switching to allow the stock Pokey's single output to pass through both left and right channels for mono operation (programs that don't support stereo), same as done on 1088XEL or Simple Stereo with U-Switch board added.

 

Speaking of the 1088XEL, a slightly different version of this board could be made to drop into and utilize the onboard mixer of the 1088XEL, thus automatically routing both channels to the 3.5 mm and the DIN-13 jacks.

 

So as it stands right now, the present proposal gives you 8 voices per audio channel output. Of course by adding an additional address line and cores this could be doubled. But at some point you would hit diminishing returns when considering CPU time available for both sound and graphics where games are concerned. A!though in a purely sound oriented application with simple graphics, the additional cores might be nice and put to use creating some great music.

[Vyper68]

As a fan of 8-Bit Chip Music in general and the POKEY in particular 'cos I'm an Atari user, I can see the appeal of just having the Audio section of the POKEY "emulated" having no electronics training i just wondered how realistic is this concept to come to fruition? and when could we maybe expect something to happen as regards production of these type of boards?

They ( POKEY's ) seem to be quite scarce at the moment in Europe and something like this would be great - maybe you could even toggle between Dual or Quad POKEY's via a switch of some type.

[foft]

On 3/19/2018 at 5:03 PM, mytek said:

I hope you don't mind me embedding the schematic image so that it's easier to talk about.

 

 

So I'm curious what P0-P7 are being used for? I realize its a dipswitch input, but to configure what?

 

And why the 3 audio channels into one, with only one channel standing on it's own?

Does anyone here know the full pinout for the quad pokey?

 

I have these from this snippet and from an A042622 photo but am not 100 sure of them!

1 CS1_N

2 RW_N

3 A3

4 A2

5 A1

6 A0

7 D0

8 D1

9 D2

10 SOD on pokey 3

11 CS3_N

12 D3

13 D4

14 D5

15 D6

16 D7

17 5V0

18 P2 on pokey 4 ?

19 CS4_N

20 GND

 

40 NC

39 P1 on pokey 1

38 P0 on pokey 1

37 P3 on pokey 1

36 P2 on pokey 1

35 P5 on pokey 1

34 P4 on pokey 1

33 P7 on pokey 1

32 P6 on pokey 1

31 BCLK on pokey 3

30 SID on pokey 3

29 AUD from pokey 2

28 NC

27 AUD from pokey 3

26 P0 on pokey 4

25 KR2 on pokey 4

24 PHI2

23 AUD from pokey 1

22 CS2_N

21 AUD from pokey 4

 

 

 

 

[foft]

Found a pic of some unpopulated boards, so need to correct a few of those...

[shupac]

18 hours ago, foft said:

Does anyone here know the full pinout for the quad pokey?

The schematic for the Major Havoc arcade game has the correct pinout for the Quad POKEY chip. If memory serves me, it looks like that's the source of the drawing posted by Mytek.

[foft]

19 minutes ago, shupac said:

The schematic for the Major Havoc arcade game has the correct pinout for the Quad POKEY chip. If memory serves me, it looks like that's the source of the drawing posted by Mytek.

Yes thanks, I started with those so good to be more confident in them. I tried to verify these on the eliminator board then I saw that the eliminator board also has some other pins are connected, though I’m not sure if any of the other arcade boards make use of them.

Edited April 29, 2020 by foft

[shupac]

1 minute ago, foft said:

I saw on the eliminator board has some other pins are connected, though I’m not sure if any of the other arcade boards make use of them.

There are four arcade games that use the Quad POKEY: Major Havoc, I Robot, Return of the Jedi, and Firefox. None of them uses any of the "extra" pins (KR2, SID, BCLK). I know of no Atari arcade titles, Quad POKEY or regular POKEY, that use K0-K5, KR1-KR2, the IRQ pin, SOD, SID, ACLK, or BCLK. On the arcade games, POKEY and Quad POKEY are used strictly for sound generation, random numbers, and reading DIP switches (and on one game, Warlords, the paddle controllers) through P0-P7.

[foft]

OK thanks this is good to know. So it sounds not useful to correct the others then (except for VCC!!), but for the record these are what I think I see in that photo (and the same for below):

1 CS1_N

2 RW_N

3 A3

4 A2

5 A1

6 A0

7 D0

8 D1

9 D2

10 SOD on pokey 3

11 CS3_N

12 D3

13 D4

14 D5

15 D6

16 D7

17 SOD on pokey 4

18 IRQ on pokey 4

19 CS4_N

20 GND

 

40 5V0

39 P1 on pokey 1

38 P0 on pokey 1

37 P3 on pokey 1

36 P2 on pokey 1

35 P5 on pokey 1

34 P4 on pokey 1

33 P7 on pokey 1

32 P6 on pokey 1

31 BCLK on pokey 3

30 SID on pokey 3

29 AUD from pokey 2

28 NC

27 AUD from pokey 3

26 BCLK on pokey 4

25 SID on pokey 4

24 PHI2

23 AUD from pokey 1

22 CS2_N

21 AUD from pokey 4

 

If anyone HAS one of these boards be good to check continuity just for knowing ?

Edited April 29, 2020 by foft

[Mathy]

Hello Mark

 

Can you tell me why you are looking for the pinout of the QuadPokey when the "simpler" versions of PokeyMax seem to be ready?  I'd expect that you would know the pinout when the PokeyMaxs are finished.  (I'm just curious!!!)

 

Sincerely

 

Mathy

[Mathy]

Hello guys

 

Can somebody please explain what the extra pins are supposed to do and what advantages using them would have?  And can these be used on the PokeyMax?

 

Sincerely

 

Mathy

Edited April 29, 2020 by Mathy

[foft]

I was pointed to confirmation of some of the pins (Thanks Neil).

Here is a snippet of the schematic for Return of the Jedi.

 

[foft]

3 minutes ago, Mathy said:

Can you tell me why you are looking for the pinout of the QuadPokey when the "simpler" versions of PokeyMax seem to be ready?  I'd expect that you would know the pinout when the PokeyMaxs are finished.  (I'm just curious!!!)

 

Well we're working on the advanced board. I just finished the layout and got interested in this for a bit of light relief. Before continuing with on with the hardware description of the next part:-)

[foft]

12 minutes ago, Mathy said:

Can somebody please explain what the extra pins are supposed to do and what advantages using them would have?  And can these be used on the PokeyMax?

 

This is another chip that Atari made called the 'quad pokey'. It was only used in a few arcade machines and there was only a little documentation on it. It was essentially 4 pokey dies on a single chip as you can see in the picture. You can read a little more on it here http://www.jmargolin.com/firefox/firefox.htm (Thanks Neil again!)

 

The pokeymax comes in a quad version (on a single die, more integrated!). However this is designed to fit into the Atari with the Atari pinout. I thought that perhaps some arcade people might be interested in using it in place of the Atari 'quad pokey', which will require an adaptor board to shift the pins around.

 

Edited April 29, 2020 by foft