There is one motherboard + crystal of kings on eBay for 800 Euro... If this was in the MVS or PGM price range I would have a look, but this is a bit much. (Edit: And obviously if it had an interesting shooter. )
Based on the cartridge pictures you should be able to cover most games with just a handful of extra flash chips, though it really depends on what the pic does.
Reading further through the Mame driver:
- /* note on PIC protection from ElSemi (for actually emulating it instead of patching)
- The PIC uses a software UART bit banged on a single output pin of the main CPU:
- the data port is bit 0x20000000 on the PIO register, the same register where the EEPROM control lines are. The serial data is transmitted at 8 data bits, even parity, 1 stop bit. It's probably
- tricky to get it working properly because it doesn't rely on a clock signal, and so, the pic and main cpu must run in parallel, and the bit lengths must match. The pic bit delay routine is just a loop.
- also it seems that bit 0x40000000 is the PIC reset.
So the question is if the PIC does some communication before the cpu loads the game, and if there is ongoing communication after the game boots. As far as I can tell at least one pic is dumped, so someone with experience of PIC assembler could have a look. It would be great if you could just leave it out...
Tracing the flash chips to the connector should give you 99% of the pinout for data and power. I assume the '138 gets address lines and selects banks. A few minutes with a caliper should give you the outline of the PCB (Though it is worth tweaking the cartridge connector size a bit to avoid short circuits: mvs-scans.com/index.php/BCS_-_Hardware_Notes )
For a multi I would replace the '138 with a PAL, to select different roms depending on game.
The post was edited 3 times, last by Fluffy ().
Well this sounds like fun. @Fluffy expect a couple PM's after I have this in hand!
And that guy is crazy. The last couple were under 300usd at open auction.
The post was edited 1 time, last by rewrite ().
Yeah I got his soccer game and it's in fantastic condition. I already had CoK or I would have bought his as well!
I really wanted that one you got, and I figured since you are converting it anyway, wouldn't you rather have one with a cartridge cover?
It looks like the cartridge cover would only get in the way with the vertical orientation of this motherboard. Ack was telling me that these ones snap in on the bare board. So we'd need to swap the whole set-up.
Part of the appeal of this one is its just one rom to remove (less room for error with fiddly smd stuff). Is the soccer game the same PCB? I know at least one in MAME looked to be *entirely* different.
The plastic stabilizers are screwed in to the motherboard via the 2 holes at the sides of (pci?) slot connector from the bottom and have groves that you use to slide the game into.
There are additional screw holes in the stabilizers that are then used to screw threw the lower 2 holes in the game boards
The motherboard that includes the plastic case also has a 90 degree riser card.
A cart can plug directly into the motherboard slot without the stabilizers installed, but you need to be careful about the short to ground issue.
Thank you for the clarification, @ack!
OK, I'm willing to send out a CoK and a Soccer and a motherboard (or two) to someone with the legit skills to make a multi, especially if that will help @rewrite get the game he really wants and to sell me the one I really want!
Ok, a bit of looking through the mame driver now that I'm at home:
So the pic used in top blade is dumped, and it looks like proper code... so one easy test (once you get the cart and the pic is socketed) is to burn this into a new pic16c727 and see if it boots.
No pic dump is linked from crystal of kings:
I'll order a PIC16C727 this afternoon and test soon as it comes in. It'll likely take longer to arrive than the game I'm sure.
@Fluffy according to the guru's site, it isn't actually a 16c727. I also can't find any mention of the chip on the internet outside of references to the Crystal System.
Yeah, I'm looking through digikey's pic device selection. Seems to be quite a lot of code to just bang out some data...
Ghidra can open the dump as 16cXX processor, and the code looks like it is doing stuff and not some random noise. The last instruction doing something seems to be at 0x6f0, after that is seems to be just filler bytes. Pic processors have some weird ~12 bit program memory, so you can't directly give a byte value.
A good candidate could be PIC16C715 or 716, which have 2k program words. The dump is quite a bit bigger, though...
I guess if someone can work out the pin connections to the bus we could narrow down how it works and what it does.
The post was edited 2 times, last by Fluffy ().
Apparently 16c715 is a obsolete: microchip.com/wwwproducts/en/PIC16C715
Still available is microchip.com/wwwproducts/en/PIC16F716
Just looking at the datasheet, it has the right pin count, and the power and oscillator pins seem to match the top blade pcb pictures:
No idea if it'll be compatible with the code...
This is what I see on my dongul pic with a logic probe /multimeter
01 <=> dead
02 <=> dead
03 <=> dead
04 <=> Pulse a little after boot then goes LOW / PIN 116 on Vrender0
05 <=> LOW / GND
06 <=> dead
07 <=> dead
08 <=> dead
09 <=> dead
10 <=> dead
11 <=> dead
12 <=> dead
13 <=> dead
14 <=> HIGH / VCC (3.5V measured)
15 <=> LOW / clock? 100ohm between pin and upper clock pin
16 <=> dead
17 <=> Pulse a little after boot then goes LOW / PIN 113 on VRender0
18 <=> dead
Oh shit, this thread is getting good....
I'm in the middle of a move, but if I can help, please let me know. I have a dedicated soccer and CoK cart. A very nice working mobo, and a very nice mobo where the battery leaked all over and is under a repair attempt by JNX right now. I'll be happy to help in anyway I can until the movers show up Tuesday, then I'm out of the loop for about 3 months.
Hold my beer...
Maybe you can just dump the patched program from mame and burn that, and not use the pic at all? Depends on how the pic is integrated into the system,
A few years ago I designed a replacement cartridge for Crystal System in the hopes of getting our hands on some undumped games. Been a long while since I thought about this project! Will have to find the box with all the goodies.