JTAG of Cave CV1000 PCBs

[Buffi]

I've been writing up some stuff about how JTAG of CV1000 PCBs work. Maybe it's of interest for some users here. Makes it quite easy to dump U4 if you have any weird revisions.

https://github.com/buffis/cv1k_research/tree/main/JTAG

[parodius]

Very interesting. Any chance of being able to access the U23/24 sound data flash chips further down the road ?

[Buffi]

Not through JTAG no

[pegboy]

So correct me if I'm wrong, but won't this allow you to convert one game to another? Other than the sound rom, you should be able to dump/reprogram the PCB code/graphics?

So for instance, with this allow me to convert a DFK 1.5 -> 1.0 or Futari 1.5 -> 1.0 and back again? I'm assuming those both use the same sound ROM so it would work perfectly?

[Buffi]

So correct me if I'm wrong, but won't this allow you to convert one game to another? Other than the sound rom, you should be able to dump/reprogram the PCB code/graphics?

So for instance, with this allow me to convert a DFK 1.5 -> 1.0 or Futari 1.5 -> 1.0 and back again? I'm assuming those both use the same sound ROM so it would work perfectly?

> So correct me if I'm wrong, but won't this allow you to convert one game to another? Other than the sound rom, you should be able to dump/reprogram the PCB code/graphics?

It's possible.

> So for instance, with this allow me to convert a DFK 1.5 -> 1.0 or Futari 1.5 -> 1.0 and back again? I'm assuming those both use the same sound ROM so it would work perfectly?

Both of these are possible. Note that both of those conversions require writing to U2, which is quite scary for a few reasons:
1. It takes 3 days to write (and another 3 to verify)
2. If your NAND has factory bad blocks (common), writing a romset without bad blocks wont work. For this case, the script will disallow it though.
3. If your NAND has bad blocks not in the bad block table, writing may fail as well
4. I haven't tested it much (see docs)

In theory though yes, you could use this for that.
Unless you are prepared to deal with the consequences of it not working (fixable, but requires desoldering/soldering), I wouldn't attempt it.

edit: Note that I haven't really looked at the structure of 1.0 vs 1.5 of these games. If it's just adding more data to the end of U2 blocks, upgrades could probably be sped up significantly by only handling the relevant pages, and downgrades might not even need changes to U2. As mentioned, haven't looked at this though!
edit2: Disregard edit above. Had a quick look at it, and suspect you want to do a full rewrite.

[Sumez]

Nice job, Buffi. It's great to finally have this sort of documentation out in the open.

[brokenhalo]

Thought these were interesting. First time I've noticed CV1000 conversions for sale. Not sure what he means by "No white plastic plug", and all the stickers have been removed, so not sure what it was a conversion from.

DFK PCB 1

DFK PCB 2

[PC Engine Fan X!]

Thought these were interesting. First time I've noticed CV1000 conversions for sale. Not sure what he means by "No white plastic plug", and all the stickers have been removed, so not sure what it was a conversion from.

DFK PCB 1

DFK PCB 2

For brokenhalo,

I'd have to assume that a cheaper Cave SH-3 pcb (like Cave's SH-3 Mushihime Tama pcb) was used for those two particular conversion jobs. Still doesn't affect the demand for a real bonafide Cave SH-3 pcb say like Dodonpachi Dai-Fukkatsu v1.5, Dodonpachi Dai-Fukkatsu Black Label or Dodonpachi-SaiDaiOuJou these days as they still command a "king's ransom" in 2024.

So does this mean that we'll see some DDP-SDOJ conversion pcbs "down the road" as well? Hmmm.....

PC Engine Fan X! ^_~

[spmbx]

Thought these were interesting. First time I've noticed CV1000 conversions for sale. Not sure what he means by "No white plastic plug", and all the stickers have been removed, so not sure what it was a conversion from.

DFK PCB 1

DFK PCB 2

For brokenhalo,

I'd have to assume that a cheaper Cave SH-3 pcb (like Cave's SH-3 Mushihime Tama pcb) was used for those two particular conversion jobs. Still doesn't affect the demand for a real bonafide Cave SH-3 pcb say like Dodonpachi Dai-Fukkatsu v1.5, Dodonpachi Dai-Fukkatsu Black Label or Dodonpachi-SaiDaiOuJou these days as they still command a "king's ransom" in 2024.

So does this mean that we'll see some DDP-SDOJ conversion pcbs "down the road" as well? Hmmm.....

PC Engine Fan X! ^_~

These are bootlegs, not conversions.

[Sumez]

PCB looks pretty convincing to me. Did people really manage to make custom cv1000 PCBs? Because that would be kinda huge...

[brokenhalo]

Looking at pics of these vs pics of a legit DFK PCB, only thing that stands out as different is the lack of stickers. Board components all seem to be a pretty 1-1 match. I guess it's possible that they could have hired the original factory to produce more boards, but it just seems more likely that these are conversions.

[Sumez]

Yeah if you're gonna make a bootleg board and not even try to pass it off as an original, there's no reason to copy the original design so closely.

[pegboy]

They are 100% bootlegs, NOT conversions. Discussed more here: https://www.arcade-projects.com/threads ... hoy.29488/

[brokenhalo]

They are 100% bootlegs, NOT conversions. Discussed more here: https://www.arcade-projects.com/threads ... hoy.29488/

Thanks for linking that. Interesting stuff. Hopefully they keep plugging away at it and figure out how to make a multi.

[PC Engine Fan X!]

A Cave CV1000D pcb as a "multi" game deal would be awesome -- just having the conveinance of selecting your favorite Cave SH-3 game "on tap" and playing it with just one pcb (rather than having to deal with multiple real Cave SH-3 pcbs which can be cumbersome -- not to mention dealing with storage issues/general upkeep with them). It's an expensive hobby as it is with arcade jamma pcbs these days.

The real question is: Would Cave issue a C&D order to stop production of these bootleg CV1000D pcbs?

Those two conversion SDOJ pcbs sold for $1,600 usd each on eBay 4/04/2024 -- still quite a bargain (compared to paying top dollar for an original SDOJ pcb in the $4,000 usd range and up). Of course, the Exa-Arcadia SDOJ port is cheaper on the ol' wallet or purse for that matter.

PC Engine Fan X! ^_~

[spmbx]

A Cave CV1000D pcb as a "multi" game deal would be awesome -- just having the conveinance of selecting your favorite Cave SH-3 game "on tap" and playing it with just one pcb (rather than having to deal with multiple real Cave SH-3 pcbs which can be cumbersome -- not to mention dealing with storage issues/general upkeep with them). It's an expensive hobby as it is with arcade jamma pcbs these days.

The real question is: Would Cave issue a C&D order to stop production of these bootleg CV1000D pcbs?

Those two conversion SDOJ pcbs sold for $1,600 usd each on eBay 4/04/2024 -- still quite a bargain (compared to paying top dollar for an original SDOJ pcb in the $4,000 usd range and up). Of course, the Exa-Arcadia SDOJ port is cheaper on the ol' wallet or purse for that matter.

PC Engine Fan X! ^_~

Only cheaper (less expensive) if you ignore the fact you need to buy a motherboard (pc) before you can play the actual game.

[Sumez]

They are 100% bootlegs, NOT conversions. Discussed more here: https://www.arcade-projects.com/threads ... hoy.29488/

Wow that's insane. I have several CV1000 boards at home, and I'd really have to do a double take to see this is a reproduction.
Would be cool to see these mass produced. But man, it makes buying CV1000 games much more of a risky minefield going forward!

[Markelov69]

I've been writing up some stuff about how JTAG of CV1000 PCBs work. Maybe it's of interest for some users here. Makes it quite easy to dump U4 if you have any weird revisions.

https://github.com/buffis/cv1k_research/tree/main/JTAG/WEB

That's intriguing! Is there a possibility of accessing the U23/24 sound data flash chips at a later time?

[PC Engine Fan X!]

Back when it was possible to get a brand new or super mint condition Cave SDOJ jamma pcb kit in 2012-2014, it was a mere $2,400 usd. Of course nowadays, it's in the $4,000 usd and up range.

PC Engine Fan X! ^_~