Donkey Kong Remixed

[ChrisP]

I've been quiet about DK Remix updates for a few weeks because I've been trying to work out how to get a plug-in board to boot up DK Remix on an unmodified DK board set.
Yesterday, I finally got a hand-wired prototype to boot up the game.   Huge relief to see it working.

I still have a way to go because I'd also like the board to be able to save high scores, let you play original DK ROMs without having to remove it, maybe allow the possibility of supporting more than one extra game ROM, and hopefully allow saving high scores in regular DK too.   Hopefully I can pull that off.

Would be very, very cool to get extra features on there.

Actually, the more I think about it, the more I feel that the ability to switch to classic DK might really be more of a requirement of this than a feature. It would be a hassle to have to remove the daughter card to go back to the normal game, and if you put a decent sized EPROM on there, there should be plenty of space for DK.

Geez, maybe you could even throw in those other games that run on DK hardware, like Herbie at the Olympics and that pool one. Or maybe not...

[tilt]

I've been quiet about DK Remix updates for a few weeks because I've been trying to work out how to get a plug-in board to boot up DK Remix on an unmodified DK board set.
Yesterday, I finally got a hand-wired prototype to boot up the game.   Huge relief to see it working.

I still have a way to go because I'd also like the board to be able to save high scores, let you play original DK ROMs without having to remove it, maybe allow the possibility of supporting more than one extra game ROM, and hopefully allow saving high scores in regular DK too.   Hopefully I can pull that off.

Would be very, very cool to get extra features on there.

Actually, the more I think about it, the more I feel that the ability to switch to classic DK might really be more of a requirement of this than a feature. It would be a hassle to have to remove the daughter card to go back to the normal game, and if you put a decent sized EPROM on there, there should be plenty of space for DK.

Geez, maybe you could even throw in those other games that run on DK hardware, like Herbie at the Olympics and that pool one. Or maybe not...

Additionally, I think there would need to be a way to prove that the version of classic DK is exactly the same as normal, as many players would like to submit using this hardware, i'm guessing.

[Sock Master]

Yes, my figuring is that nobody wants to have to plug or unplug the board every time they want to switch between normal DK or Remix.

I'm going to do it a bit differently than the D2K board.   I'm not actually going to include normal DK roms at all.   The board is going to switch to the on-board DK PCB ROMs when running normal DK.  If you have the Japanese ROMs, or Ladder cheat ROMs, or whatever... that's what you're going to get.    Hell.. I think maybe if you plugged it into a D2K board, it ought to probably still run and it would switch to D2K instead.

I did more hardware tests today and successfully got it to switch between Remix and on-PCB ROMs.   (Feature not implemented yet or anything, this was a test to see if the functionality actually works.)


I guess the big question would be... How could it prove that it is running normal DK ROMs to the satisfaction of someone scrutinizing the machine during a score submission?   Have a boot up screen report on-board ROM checksums?

And the second big question...  I'd also like to support high score save *in* normal DK.  But again, it won't be running a modified DK ROM to do it.  The board is going to inject the saved score data *without the Z80's knowledge that anything happened at all*.   Is that on it's own, enough to disqualify score submissions?   I'm going to try to include an option to disable this extra feature, even though it won't alter the gameplay in any way as no Z80 program code gets modified (just high score data.)

The board has a microcontroller on it to do this stuff.  It won't be the Z80 saving the high scores.  It won't mess with classic DK gameplay or game code, the microcontroller will run independently and monitor if the Z80 is reading or writing the high score table.

[f_symbols]

John, you sir are literally a fallen angel <wings>  <wings> Thank you so much for all you've done and continue to do for this game/community. Can't fkn wait!

[Jonesy]

Have to echo what Ethan said

What you're doing here is awesome and I'm definitely grabbing myself some of this. The fact that your circuit board will allow for whatever ROMS the cab has in situ to operate when required is definitely a bonus.

Top work sir! 

[Sock Master]

Aww, thanks

I got the microcontroller to detect when the Z80 wrote to a RAM location and know what it wrote..  I think that was the last absolutely essential function needed for high score saving.   So that makes my little prototype hardware-complete.

The next step is to design the PCB layout... and then see how much of a financial hole it'll put me in to get some boards ordered..yay!

There's still a way to go.  I still have to write the microcontroller firmware, then the boot menu after that.  But I think I should be able to get the first boards made by the end of the year.

And after that? who knows.  But the boards will be DKjr, likely DK3, Mario Bros, maybe Crazy Kong compatible and probably some others too if somewhere down the line there's interest in other arcade projects.

[tilt]

Wow this is fantastic.  So from what I gather as of now, the whole DK Remix game is running on an eprom chip on the card itself, rather than using any of the original code?  If this is true, this opens up the possibility to easily swap out many different rom hacks and revisions, possibly even DK JR stuff?  I am not entirely sure on that last point, but either way this project is making absolutely insane progress, keep it up sir!!!!!! 

[Sock Master]

Sort of, yes.  In order to keep the design small and affordable, the game ROM and save RAM are actually in the microcontroller rather than separate components on the board.   But essentially yes, DK Remix does not use the DK ROMs.

The microcontrollers come in various ROM sizes, and the largest of them would actually be able to hold 7 versions of DK (depending on ROM size - Remix is larger than DK, and some of the space on the chip has to be used for firmware.)

Yes, the board works just fine on DKjr hardware, so if it were loaded up with DKjr ROMs, it could be used to run alternate versions of DKjr too.

But, it can only change program code, not graphics data or sound code.  So, we couldn't actually run Herbie at the Olympics or that Pool game as Chris P joked about.   Stick a DK Remix board into a DKjr. PCB and it'll boot up Remix... but it's going to play with Jr. graphics characters... all mixed up graphically.

[ChrisP]

Oh, OK, I see what you're saying. It'll be JUST the Z80 code, and the video and sound ROMs are untouched. I could be wrong about this, but I think the D2K kit actually has everything - Z80 code, graphics, and (digital) sounds, all on his one EEPROM, bypassing all the game data on the board completely (I could be wrong).

How are you planning on connecting the add-on board? Will it go in the Z80 socket like D2K, are are you perhaps doing something with the ribbon cables? I ask because you said something about being able to have the D2K kit installed at the same time, so I was trying to picture how that would even work!

[Sock Master]

The D2K board just plugs into the Z80 socket, like this one, so in theory you could plug a D2K board into the Z80 socket and then this board into the Z80 socket on the D2K board..  I don't have one, so I can't say for sure if it'll work, but in theory it should be possible if they don't have some sort of addressing conflict...  It'd just be interesting to see if it works.  Boot Remix, and then switch to PCB ROMs and it should then boot D2K.. From there you can boot it's version of regular DK (with high score save).  It's just a an idle curiosity, wondering if it'll work like I think it would.

D2K doesn't change graphics or sound ROMs either.   It re-uses existing graphics in clever ways to make it look like there are new sprites in the game.  Only more elaborate hardware modifications like the Double Donkey Kong PCB modification allow switching of graphics & sound ROMs.  But that is not a simple thing to install as it has to tap into a bunch of different sockets on the PCB, requires soldering and adds wires to send signals to those points.  You have to send your PCB away to get a modification like that.

So, the DK Remix board is going to be simple - just plug it into the Z80 socket.  But it could hold several versions of DK, and also let you run your original PCB ROMs without having to pull it out.

[Sock Master]

Well, everything seems to be checking out bit by bit.   I have a hand-made prototype board.  I have a nice PCB design for board production.  I made a nice menu for settings and options.   DK Remix now supports saving scores and extra features like switching games and going back to the menu.  The hardware design allows features like saving scores and switching back to menu even from regular *unmodified* DK PCB ROMs.  (Implementation is super tricky... it's the board that does the tricks because the Z80 is just running normal DK code.)

So, now I have to cough up about 1000$ to get some blank boards made.  Populate and assemble them, and then If I sell 15, I probably break even.

I'm not going to ask for pre-orders or anything.  I don't even have a store, or a business... but the first few boards ought to be available in a month or so.

Fun times ahead.

[WCopeland]

Any way I can get a quote on a board, or at least be put on the waiting list? I'd like to set aside the funds to buy.

[Sock Master]

It'll probably be 80$ plus whatever it costs to ship.   I'm only going to have parts for 5 boards at first.  The money from the first 5 will go into getting more parts to build more boards, etc..

I'll set aside the first one for you.

[f_symbols]

Ill take one as well

[danman123456]

At this point heck yes. For that price range I would like one as well.