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Darksoft CPS-1 Multi: Preview / Sneak Peek / Information - FINALLY!

I have something like this in my Megadrive/Genesis; the crystal is replaced with a DFO module that has the same footprint and is programmed with the two frequencies used by the console. There's then a logic pin that you either drive high or low to select which frequency you want. You can wire that to a simple toggle switch, or drive it from something else, in this case a region switcher tied to the reset button.

IMG_2576.jpg


You can see there is a row of unpopulated headers on the DFO that you can use to (re)program the chip with other frequencies, 10 and 12 MHz should be doable. You just have to be careful when changing the CPU frequency that the system doesn't get confused and lock up, at least on the Megadrive it halts the 68k CPU when switching.
 
bodgit said:
I have something like this in my Megadrive/Genesis; the crystal is replaced with a DFO module that has the same footprint and is programmed with the two frequencies used by the console. There's then a logic pin that you either drive high or low to select which frequency you want. You can wire that to a simple toggle switch, or drive it from something else, in this case a region switcher tied to the reset button.

IMG_2576.jpg


You can see there is a row of unpopulated headers on the DFO that you can use to (re)program the chip with other frequencies, 10 and 12 MHz should be doable. You just have to be careful when changing the CPU frequency that the system doesn't get confused and lock up, at least on the Megadrive it halts the 68k CPU when switching.
Click to expand...
Very nice, Im sure a similar solution could be done for the CPS1 A boards, thanks!
 
bodgit said:
I have something like this in my Megadrive/Genesis; the crystal is replaced with a DFO module that has the same footprint and is programmed with the two frequencies used by the console. There's then a logic pin that you either drive high or low to select which frequency you want. You can wire that to a simple toggle switch, or drive it from something else, in this case a region switcher tied to the reset button.

IMG_2576.jpg


You can see there is a row of unpopulated headers on the DFO that you can use to (re)program the chip with other frequencies, 10 and 12 MHz should be doable. You just have to be careful when changing the CPU frequency that the system doesn't get confused and lock up, at least on the Megadrive it halts the 68k CPU when switching.
Click to expand...
Where did you buy that PCB with dual quartz?
 
Nimmers said:
How long before someone makes a filter board with a DFO on it? :)
Click to expand...

The DFO needs to be as close as possible to the original crystal location to avoid interference - would be cool if it could be on the filter board though :)
 
twistedsymphony said:
it's not exactly a surprise that this was a feature that people wanted.
Click to expand...
Right, I've known about the combo problems of SF2:HF when run on a 10mhz A-board for over a decade now.
Originally I didn't think it would be a major problem/feature worth exploring... I mean the user could just swap the A-board easily.

What changed for me?
Well I didn't expect Key writing/original ROM operation.
I thought all CPS1 ROMs would be patched (like we've done for conversions, or perhaps comparable to the original operation of the CPS2 multi ie decrypted ROMs pre-key writing).

If we are pushing for "the ultimate OMG CPS1 multi" as it seems the quest now is...
Yea my 0.02$ you want perfection, you can't call it that without addressing the clock speed issues.
 
honestly I'd be happy if the multi just includes a solder point that goes high or low depending on which frequency the game requires (heck even controlled by the config file for the game as opposed to anything fancier. Then those who care can install the DFO and wire it up themselves.
 
What @twistedsymphony said would be the ideal situation. Maybe someone could create a little mod board specific for the CPS-1.

An entire filter board would be awesome but also might be cost prohibitive, especially shipping wise overseas on top of the initial multi cost.
 
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