(Regular) Pokey in FPGA?

[woj]

20 hours ago, pcrow said:

I'm under the impression that the various replacements for Pokey sometimes have subtle timing issues.

When I was playing around with the MiSTer the Joyride demo would not work, in the process of trying to make it work (IIRC I did not succeed) I ran the ACID 800 tests, and Pokey timing was IIRC the only crucial failure / incompatibility

[+mytek]

35 minutes ago, reifsnyderb said:

They are not one-for-one replacements, either.

Agreed. If they were then they would meet two basic criteria.

1. They would work identical to the original in all regards (e.g., timing, output quality where applicable, ect.), and electrically be indistinguishable from the original it is meant to replace.
2. They would stay within the footprint and height of the original chip (e.g., no overhang, or increase in height).

In all cases the present day replacements fail in at least one or both regards.

[+-^CrossBow^-]

17 hours ago, _The Doctor__ said:

You use the real pokey from the cartridge and install a hokey or pokey 1 in the cartridge.

Now you have a working cartridge and a working Atari 8 bit.

Except that even currently, the HOKEY isn't a total drop in replacement just yet for the games.

[+scorpio_ny]

1 hour ago, mytek said:

Agreed. If they were then they would meet two basic criteria.

1. They would work identical to the original in all regards (e.g., timing, output quality where applicable, ect.), and electrically be indistinguishable from the original it is meant to replace.
2. They would stay within the footprint and height of the original chip (e.g., no overhang, or increase in height).

In all cases the present day replacements fail in at least one or both regards.

While I agree that there is room for improvement, I am still thankful the modern replacements exist. As time goes one, we will hopefully see improvements in performance, footprint and price down the road.

[foft]

Those are anything but basic criteria. The more you dig the more details you find.

https://en.m.wikipedia.org/wiki/Coastline_paradox

Now a cheap microcontroller based one could be done. How much would it save though? The bom of pokeymax 1 was 18USD + pcb (single sided, 2 layer) + soldering.

 

There is also the option of new chips:

https://developers.google.com/silicon

[Overange]

1 hour ago, foft said:

 

 

There is also the option of new chips:

https://developers.google.com/silicon

When will PCBWAY start offering this service?

 

[+mytek]

3 hours ago, foft said:

Those are anything but basic criteria.

 Probably what I should have said is that the criteria about size and functionality should be the target for any replacement chip, with functionality being all important. And obviously size should be such that it can fit into the greatest number of systems that would use it.

 

Below are two example replacements for the infamous C64 SID chip. And as can be seen neither is any bigger than what it is meant to replace. And as far as I understand it because of me being a relative newcomer to the C64 scene, both of these do a fine job of mimicking the functionality of the original chip, albeit minus one feature that never got used (external audio input).

 

 

Bus timing is usually the crucial item when developing a replacement. Ideally that timing should be pretty much spot on and match the original chip from an interface point of view. That's what really makes it a drop-in-solution. Legacy hardware and software shouldn't have to be altered in order to use the replacement or to have it work the same in the application as the original did.

 

3 hours ago, foft said:

The bom of pokeymax 1 was 18USD + pcb (single sided, 2 layer) + soldering.

Based on that, I guess PokeyMax has quite a mark-up by the time it gets to the retail package, which last I heard was hovering around $140. I realize it comes with a lot of bells and whistles (e.g., Stereo, COVOX, maybe even SID emulation), but as the OP who started this post was pointing out, is there a standard Pokey in FPGA (Edit: or could there be), and one that brings that down to a lower price point. Not everyone who needs a Pokey requires all the extras that PokeyMax brings.

 

Edit: The PokeyONE is not a true Pokey replacement for our systems, since it lacks the SIO and likely Paddle inputs.

[+kheller2]

Is it even possible to redo pokey on a single modern programmable chip?  Even PokeyMax required ancillary chips to do pot charges, etc.

 

I think we should just all start wire wrapping this: http://www.retroclinic.com/leopardcats/bbpokey/breadboard_pokey_project.htm

 

 

[foft]

Regarding extra chips. There are level shifters, comparators and the audio output stage.

 

I found after my designs that the fpga has comparators built in for the lvds inputs. I worked out how to use them in the sidmax design. So the lm339s could go I think in my next version, probably. Then I would probably have room to replace the keyboard io expander with real fpga lines, which would allow tighter keyboard polling timing.

 

The lack of 5v tolerance on FPGAs is annoying and needing a voltage regulator for 3.3v. That adds more chips. Interestingly the cpu based ones for c64 do seem to accept 5v, at least I see no level shifters on the backsid. The Armsid is hidden! There are 5v tolerant fpgas but I think not in this size.

 

From what I know Armsid is better than Backsid, though perhaps it improved since the reviews I read.

 

I don’t really like replacing logic chips with cpus, just feels wrong somehow. Though everyone is into that now. I say this as someone who was very into emulation on the handhelds: gp32, gp2x, pandora etc. I prefer logic gates and registers!

 

I wanted to add: pokeymax v3 is much more expensive to made, bigger fpga, 4 layer and 2 side parts. 
Not sure what is going on with v2 pricing. Perhaps some were made with expensive chips at the end of the shortage. I’d expect more like 60-80USD after failure overhead, extras, support costs, markup, though it’s not my department.

[foft]

Two more things.

 

Prices from a few years ago before the chip crisis:

 

It will be more now after inflation but not THAT much more!

 

As for the board size. I thought I did ok relative to the c64 fpga one:

 

My sidmax (2021):

 

Edited March 12 by foft

[foft]

6 hours ago, woj said:

When I was playing around with the MiSTer the Joyride demo would not work, in the process of trying to make it work (IIRC I did not succeed) I ran the ACID 800 tests, and Pokey timing was IIRC the only crucial failure / incompatibility

Joyride runs fine on Pokeymax and EclaireXL. Not sure what is up with the MiSTer since its based on the same logic. Perhaps a drive emulator bug?

 

Edit: Double checking! Errr, pt2 won't load using RespeQt 5.3. OK, I need to check this out, I love this demo! I'll do some tests and provide a new firmware in the coming weeks,

 

Edit 2: Pt2 working on EclaireXL with the same pokey core (I'm testing a new core). Ho hum!

 

Edit 3: Haha, put my original pokey back into my 600XL and it fails at the same point! So its something with RespeQt and my 600XL + joyride. i.e. Not a problem with the pokeymax. Phew.

 

P.S. So EclaireXL to quote NorthridgeFix 'Better than factory' 🤩

Edited March 12 by foft

[+mytek]

1 hour ago, foft said:

My sidmax (2021):

 

That looks sweet 👍

 

Didn't know you were doing stuff for the Commodore. I tried to find the website for Retronics but only found a FaceBook page which appears to require a log-in (I don't do FB). Is there a regular website for this?

[_The Doctor__]

2 hours ago, foft said:

Joyride runs fine on Pokeymax and EclaireXL. Not sure what is up with the MiSTer since its based on the same logic. Perhaps a drive emulator bug?

 

Edit: Double checking! Errr, pt2 won't load using RespeQt 5.3. OK, I need to check this out, I love this demo! I'll do some tests and provide a new firmware in the coming weeks,

 

Edit 2: Pt2 working on EclaireXL with the same pokey core (I'm testing a new core). Ho hum!

 

Edit 3: Haha, put my original pokey back into my 600XL and it fails at the same point! So its something with RespeQt and my 600XL + joyride. i.e. Not a problem with the pokeymax. Phew.

 

P.S. So EclaireXL to quote NorthridgeFix 'Better than factory' 🤩

Sounds like RespeQt might need some TLC, find that thread or their git hub and file a report with all that they need to recreate the issue

[foft]

7 hours ago, mytek said:

That looks sweet 👍

 

Didn't know you were doing stuff for the Commodore. I tried to find the website for Retronics but only found a FaceBook page which appears to require a log-in (I don't do FB). Is there a regular website for this?

https://retronics.eu
 

Yes and no! Pokeymax is not listed that I can see. Also the English version is shorter than the Polish one - for the language agnostic projects.

 

So it’s a secret product! I need to chat a chat with @Duddie clearly in pricing and visibility.

[+DjayBee]

33 minutes ago, foft said:

https://retronics.eu
 

Yes and no! Pokeymax is not listed that I can see. Also the English version is shorter than the Polish one - for the language agnostic projects.

 

So it’s a secret product! I need to chat a chat with @Duddie clearly in pricing and visibility.

And if Pokeymax v1 is so much cheaper than v2, it might be worth a re-release.

[foft]

It has been great having someone push me to:

• improve my product from the abbuc version v1
• make these available
• make labels
• a manual
• design a box
• arrange for construction
• flash them!
• ship them out
• handle customer relations, support them etc etc.

Lets all give a big hand to @Duddie.

 

I'm now leaning towards opening all the design files, once the current vendors sell their existing stock. To be confirmed.

Edited March 13 by foft

[foft]

8 hours ago, _The Doctor__ said:

Sounds like RespeQt might need some TLC, find that thread or their git hub and file a report with all that they need to recreate the issue

I tried the Latest 5.4 release and that failed too. So I checked it with a 1050 and pokeymax - that combination works. Might be that the app has a timing bug rather than a respeqt issue though.

[+DjayBee]

50 minutes ago, foft said:

I tried the Latest 5.4 release and that failed too. So I checked it with a 1050 and pokeymax - that combination works. Might be that the app has a timing bug rather than a respeqt issue though.

I made a posting on the ABBUC forum, pointing to here.

JoSch, the current maintainer of RespeQt, has left AtariAge several years ago.

[+DjayBee]

@foft People on the ABBUC forum ask if this is the demo you had problems with:

https://www.atarimania.com/demo-atari-400-800-xl-xe-joyride_s11309.html

 

If yes, then two members started it successfully via RespeQt.

 

Are you willing to either jump over to the ABBUC forum or on JoSch's discord for RespeQt?

Copying the communication back and forth between ABBUC and here is not really effective.

[woj]

11 minutes ago, DjayBee said:

 

If yes, then two members started it successfully via RespeQt

On my side I can say that it was not as much as starting it (that works even with the SIDE3 ATR emulation IIRC), but rather having the subsequent parts load where the demo loads from the disk *while* playing some Pokey music and animating stuff.

[+DjayBee]

Just for completeness:

Since you are located in Sweden and Switzerland, I suppose that you have PAL machines.

Correct?

[woj]

10 minutes ago, DjayBee said:

Just for completeness:

Since you are located in Sweden and Switzerland, I suppose that you have PAL machines.

Correct?

Well yes, even though I do have an NTSC one too (kind of curious what Joyride would do there actually). But just to be clear, my complaint was not about RespeQT, but MiSTer, I just wanted to underline which part of Joyride loading is most problematic 😉

[foft]

Yes it’s that demo and loading the 2nd part that fails. I get a red screen.

 

PAL 600xl

Edited March 14 by foft

[foft]

3 hours ago, DjayBee said:

Are you willing to either jump over to the ABBUC forum or on JoSch's discord for RespeQt?

Copying the communication back and forth between ABBUC and here is not really effective.

Thanks. Hopped over there to post some info. 

[Overange]

 

This is an interesting watch, Shame the Pokey does so much more than the SID, as the PICO could be a great Low cost POKEY replacement.