Thursday, June 1, 2017

Where are we now?

Two years is a long time for an update and we have a lot to talk about!
As some of you already know, finding an affordable yet large enough FPGA to hold the Pole Position design has always been a challenge.   External memory is always an option, but PP has so many clients in need to memory all the time (multiple CPUs, multiple layers of video hardware, etc) I would have to architect another whole layer of memory management hardware just to pull it off (believe me... I started going down that road).  Then Xilinx suddenly released it's 7 Series family of FPGAs and guess what... even their somewhat smallest solution seemed to have just enough to hold the PP design.  Success!! Well.. almost.

Xilinx decided to only release their 7 Series FPGAs in BGA packages.  Having never done a tight-pitch BGA based PCB design before, I proceeded cautiously.  I had the PCB design pretty much finalized but needed some layout guidance so I started working through my network of fellow engineers who might have some experience in this area and could give me some guidance.  One of which was Clay Cowgill... fellow arcade collector, embedded systems engineer, and all around basic hardware nut like myself.  While my days are spent designing hardware at the chip (semiconductor) level, Clay is working on hardware more at the systems level.  Not only that, but for most (if not all) of his company's projects he 'is' the PCB layout guy.  So what started as a few emails of "Hey how do you suggest I do this?", and "What types of things should I be concerned about here?" ended up as "Wow your system is pretty simple compared to the stuff I have to mess with... why don't I just lay this board out for you?"  This was pretty much a no-brainer for me.  My work schedule is pretty rigorous and Clay's work experience is filled with PCB design and manufacturing.

Things were off to a very rapid start when all of a sudden Clay got word that the city just approved his request for a Ground Kontrol expansion.  Good news for him... no so good news for me. :)  Time dragged on as most construction projects do and what started out as a 7 week venture ended up a 7 month venture.  But things finally wrapped up and Clay has able to finalize the prototype hardware.

So where are we now?  I just got word that Clay has prototype hardware in-hand and in starting assembly.  Once he has a few made up and is confident everything is as it should be he'll pass them my way and I'll be integrating the PP design into the FPGA.  I already have adapter cards made up (more on that later) and have also started working on the menu system.. Haven't finalized on the name just yet but Pole Position Multi has a nice look to it:

So my goal is to have a working prototype this month.  Does that mean production is just around the corner?  Not necessarily.  I'd like to get the proto into John's hands so he can bring it over to the Hangar and put some burn-in time on it. Get a sense of what features we may want to add... etc.

That's it for now... gotta get back to work but should I dare say that 2017 may just be the year we finalize this long overdue project?  Man I hope so!


Wednesday, November 19, 2014

You Hear Somethin?

1st signs of audio life.  Still need to work out the discrete sounds but here are some speech samples recorded directly from the FPGAArcade Replay board running a reduced PPClone.

Wednesday, October 8, 2014

Test Screen on the Replay

After pulling out the Z8002 cores and all the road+car video logic I was able to get the design to fit into the Replay's FPGA and get to the self test screen.  (finally... sheesh)

Now to get the joystick connected up and try the audio hardware...

Thursday, July 17, 2014

Time to trim the fat

So I've realized real quick that the PPClone design will simply not fit into the Replay board as-is.
Looking at the ROM list (, there's 168kB worth of ROM info to store (nevermind the ram).  The Spartan-3E on the Replay only has enough room for 73kB.  So something's gotta go or I need to abandon the Spartan-3E.  I hate to do that since it's so attractive from a pricing standpoint so I'm looking at the ROM contents themselves to see if any savings can be made.  (large portions of memory with the same patterns in them)

Another possibility would be to store them in external RAM but I'm not sure if I can get the data to the subunits in a timely fashon.  We'll see....

Monday, May 19, 2014

PPClone update on Arcade Outsiders podcast

Last week I sat in on the Arcade Outsiders podcast for a quick interview and update on the PPClone.

Catch the full episode here: