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SCPH-9001 MM3 on alternate chip (PIC12F508), works, kinda
SCPH-9001 MM3 on alternate chip (PIC12F508), works, kinda –
I posted to EurAsia too, to get more views by the Old School PSX hardware hackers and modders, thanks!
Programmed the MM3 HEX USA into a PIC12F508 because I wanted to see if I could use the much cheaper and reusable flash model of the chip. I understand the signals are the same, but I'm not sure if you need to specifically use a different include line for the 12F508 than the 12C508.
Anyway, I used a JDM style programmer (OLIMEX PIC PG-2) and PICPgm. PICPgm has specifically supports the PG-2 and the PIC12F508. So I flashed the PIC, and proceeded to wire up a pin header for the chip so I could remove it and reprogram if needed.
I'm pretty good soldering, and I used a 30W with great care and speed on the smt contacts, then I tested connections with my DMM. I used the modchip soldering guide on EurAsia. However instead of the 22awg wire for Vdd Vss and Vpp, I used some 26awg that looked good. The other pins I used 30awg solid wire (wire wrapping wire). I wired the chip to the pin header and put the chip in the header. I could make all the wires 26awg, and even make Vdd Vss and Vpp 22awg wire. I used my DMM to check the continuity between the actual legs of the IC and the points on the PSX motherboard.
Now, backups boot ok, but if I power off and switch backups, the next time the psx boots it says to insert a Sony Playstation Disc, then I power cycle again, and it works.
Diagrams for 7-wire used - MM3 Diagrams from EurAsia (the first one).
I am not a PIC program writer, but I have programmed some things, I could probably check some PIC programming tutorials online and get more familiar with the source code and modify some Old Crow 4-pin source to work with the 12F508 (maybe it just needs a change to the include stuff).
Sooo, not sure if it is hardware or software related what I am seeing. I could also try some other hex dumps for different modchip versions.
Could be I just need to rewire the chip, or test voltages....
Another troubleshooting test would be to buy a PIC12C508 PDIP, do the OTP and see if it behaves the same with the MM3 HEX, then I may know if it is the HEX/chip combination or not.
the 4-wire old crow was ported to a 12F629 PIC from a 12C508 PIC.
I have tried the 12F508 and never had any real luck, so I stayed using the 12C508.
They cost a little more, but you know it will work 100%
Thanks for the input, I will get the CMOS version and give it a try.
When you tried the 12F508, with not having any real luck, did it partially work, like what I had happen?
Just curious... thanks...
List of problems I had. Programmed 10 chips with different settings.
1. Would not boot any games even originals
2. Boot rate 2 out of every 5 which equals about 40% boot rate
3. Stealth worked 1 out of 8 which equals about 12.5%
Interesting, thanks for the info.
I got the PIC programmer and ICs from Mouser, overall it was a pretty good deal, but next time I may try Digi-Key unless for some reason the local electronics store has the 12C508 (pretty large one actually). Of course I will have to order stuff for other PIC projects to justify the cost of shipping, lol.
EDIT: Hmm, looks like Jameco is a better deal, unless they don't do USPS shipping....
What is the difference between the PIC12C508A and PIC12C508? It isn't immediately obvious to me...
If you go to mouser electronics and search the PIC12C508 for the PDIP-8 choices there are 6 different types, but the PIC12C508A-04/P is cheapest. I took digital electronics a long time ago, but it was just an intro. I don't know if the modchip code needs more than one timer, I suspect not. Then there is the program memory size, but 768b is the highest, so I'm sure that's fine. This is the working memory for the code, obviously. Anyway, I have a feeling the modchips don't need 8 timers...
Jinn, do you have a local shop or do you order online?
Last edited by breakdaze; 11-22-2011 at 03:24 PM.
You can use
I order online from Thailand, only thing I hate it takes about 3-5 weeks.