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PS1 Playstation scph-7502 (PU-22 PCB) modchip question and modchip diagrams request

Vorde

Member
Nov 18, 2019
21
8
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It's not necessary for Mayumi - that uses the external clock setting. If you were using the MM3 code then you do need to make sure to restore the cal value if your programmer doesn't do it automatically (this is why some people thought that MM3 was unreliable).
Is there a way to do this manually?
 

Trimesh

Donator
Donator
Registered
May 30, 2019
240
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Is there a way to do this manually?

If you know what the correct OSCCAL value is, then you can just put it in the last location in memory as a RETLW instruction (0x34xx where xx is the value) - if you don't, then you either need to tweak the value until it works or use a programmer that can work it out (some the microchip tools have a function for this).
 

provato

Member
Original poster
Registered
Nov 8, 2019
23
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Update: I was finally able to program a 12f629 chip with mayumi v4.0 and install it on a pu-22 board psx.
Anti-modchip, original and cd-copies run perfectly fine now. I really wish there was a way to burn the .sbi (libcrypt) subchannels file on cds, so that I don't have to patch libcrypt games.
The 12f508A was a pain in the @ss to program with my programmer (GQ 4x4), and since I am on a budget, I really don't want to buy another programmer just to write the pic12f508A or pic12c508.
For anyone interested, I'll describe the problem with writing to the 12f508 with this particular programmer:
-I could successfully erase the chip
-I could write to the chip and verify what was written after writing, while the chip was still on the programmer.
-After removing the chip from the programmer and then reinsert it and read its data, half the data or more was missing!!! so verification failed after removing and reinserting, but not as soon as it was written. (Strange I know)

I also purchased a c-sync RGB scart cable from RGC (UK) and I 'm very happy with the picture on my sony KV-29FX30E. (I use CRTs for authenticity in picture and lightgun compatibility). I also found a dexdrive for psx memory cards in a bargain price and now I'm archiving my saves on pc/sd card much more easily! (previously I used the ps2 ulaunchelf method for saves archiving). Next steps will possibly be a cd-access bi-colour led (voultar's led mod), maybe a psio or similar parallel port ODE if the game compatibility gets better that it is now, possibly a dfo mod and purchase of some peripherals I like (mouse, fighting stick, dance mat). Also my pal console collection gets bigger (recently bought pal atari jaguar, pal nes & snes and pal mega drive 1), so the modding will go on... :p

Thank you everyone that helped me here with this mod install :D
 

provato

Member
Original poster
Registered
Nov 8, 2019
23
7
3
Thanks for this link! I'll definitely burn some cds with clone cd and test them on real hardware with the mayumi modchip
 

ibra11

New member
Apr 27, 2020
1
0
1
Hi,Happy New Year,and i have a PSX SCPH-7002 with PU-20 PCB what is the best MM3 or Mayumi v4?