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:

Friday, October 4, 2013

Blkdog7 pays a visit

John Jacobsen (aka blkdog7) stopped by for some parts the other day and we fired up the PPClone for a sec to show the status.

Skip over to 1h 18m 02s to see the clip.

Thursday, August 15, 2013

Test Screen Hurdle Success!

Finally got through that test screen hurdle. A lot of 06xx and 5xxx custom stuff to figure out. In the end I decided it was worth the time to just work though the disassembled Z80 and document everything. I figured out about 80% of it all. It was actually pretty fun.. I haven't had to do so assembly since college.  ;)

That allowed me to pinpoint exactly where I was running into trouble.

Then I ran into some Z8002 instructions my core didn't support yet so I put in a simple workaround until I can get that stuff implemented.

I also wrote up an arcade video to LCD interface so I can work on the design without needing that arcade monitor.

Long story short... I'd say we're making some headway: