IMPORTANT: Possible incompatibity issue with DK Remix board

[Sock Master]

A small order of Sharp Z80A chips came in today, so I'll have a few on-hand if someone with the incompatible NEC chip wants to order DK Remix.

They cost me 10$ each so I can just add it at cost if someone needs one.

[Simpsons99]

I need one for my 2nd dk board set

[Sock Master]

It seems I made a grave error when I ordered those chips and didn't notice that they were Sharp LH0084A chips instead of Sharp LH0080A chips, and they're not CPUs at all, but some other peripheral chip.

So, I have useless chips and no Z80As for people with the NEC chip...   (insert angry face here)

[Simpsons99]

any idea when next set of boards are going to be ready?

[Sock Master]

I'm kinda starting to pull my hair out because the chip I'm waiting for to complete the boards is quite late at actually getting here.   Whenever it actually comes in, I can start shipping more boards the next day after.

The next set *after* this set should not take so long.

[Simpsons99]

that's great!  have you found someone else to buy the chips from?

[Sock Master]

Yeah, I got tired of waiting so I ordered more chips from a different supplier.

[Capone27]

Got my remix board today!
Didn't check before hand I have the nec z80 chip....

Not to worried about it, I plan to buy another board set.

My question is can I take the z80 chip from my Dkjr or Dk3?

Thanks
Capone

[Sock Master]

Yes, if you have another arcade PCB that has a Zilog, Sharp or other Z80/Z80A CPU in it, it'll work if you move that chip into your DK/Remix board.  Chances are the NEC D780C will probably work fine in the other arcade PCB as well.

[ChrisP]

Yes. I had a Z80-C in my DK, and a Z80-A in my Junior and my Popeye.

I put my Popeye's Z80-A into the Remix board, put the Z80-C into Popeye, and everything is fine. DK likes the Z80-A that was in Popeye, and Popeye likes the Z80-C that was in DK.

[Capone27]

Awesome!  Thanks!

Capone

[Sock Master]

I probably should have added an update to this thread some time back..

I spent most of 2016 testing all sorts of things, looking into clues to figuring out solutions to the NEC-D780C compatibility issue.

Throughout 2016 I built prototypes trying out all sorts of parts from different manufacturers, made slight changes to the timing in the microcontroller firmware code, etc... Every now and then a Remix kit showed signs of improved NEC-D780C compatibility and I took note.

By the end of 2016, compatibility improved bit by bit.  If I used exactly a certain combination of parts from certain manufacturers it started being NEC-D780C compatible.

At the start of 2017 pretty much all Remix kits I built were NEC compatible.  Around DK Jr Remix's release, all Remix kits were NEC compatible.
Right now, even if some DK Remix vendors might still state they're not compatible with the NEC-D780C on their web site, they actually are.

It took time to work out all the clues because of the complex interactions between different signals across different chips from different manufacturers, but even the NEC-D780C plays nice now.

[danman123456]

Nice sir!!!

[ChrisP]

I'm actually really glad you mentioned this, because I haven't yet gotten around to getting my DK Junior Remix, and I had to swap Z80s to make the original Remix work on my DK PCB.

Or was it Popeye I swapped with? 

Well, at any rate, useful info...

[YesAffinity]

Congrats on puzzling out the fix!