[Tutorial] Making your own PS1 Modchips

Discussion in 'Modding and Hacking - Consoles and Electronics' started by Mord.Fustang, Mar 7, 2015.

  1. Bad_Ad84

    Bad_Ad84 The Tick

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    Mayumi 2.1 for pu7
    Stealth 2.8a for pu8
     
    Last edited: May 16, 2016
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  2. Kwyjib0

    Kwyjib0 Member

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    Ok I'm about to give up on this stupid K150. What is the most reliable way to flash 12C508As? I have a bunch of them so I don't want to get something that is incompatible. Has anyone tried a PICkit?
     
  3. Kwyjib0

    Kwyjib0 Member

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    Ok got it to work using a Mayumi v4 hex. I'm guessing the issue was with the Oscal value, since MM3 uses it and Mayumi v4 doesn't. I don't know what I was doing wrong, but I also have no idea which driver and version of Microbrn I'm supposed to be using with this k150, and the seller won't message me back.

    Is there any reason to use MM3 over Mayumi v4? I think I'm just going to stick with Mayumi unless there is a compelling reason to use something else and revisit this if I end up owning an early model PS1 and need stealth 2.8 or MM2.
     
  4. Bad_Ad84

    Bad_Ad84 The Tick

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    Mayumi v4 is fine, I supply that and not mm3.
     
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  5. LeHaM

    LeHaM Site Soldier

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    so whats stated in the first post is fine but use Mayumi 4 instead of MM3?

    Anyone have links to all the files?
     
  6. Kwyjib0

    Kwyjib0 Member

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    I'm no expert on this, but it's my understanding that Mayumi v4 is more reliable since it uses the timing from the board rather than the internal oscillation of the chip, which makes it more in sync with the PS1. I have no idea if I explained that correctly, but the general consensus seems to be that Mayumi v4 is just better than MM3.

    Here is the pack I downloaded, but I can only vouch for the Mayumi hex because that's the only one I got to work:

    https://mega.nz/#!0sU10AgL!vv9U4mhn4_zjzZBvml0d8d90XFpBg_P4byPAonW2BEk


    Here's another resource:

    http://www.eurasia.nu/modules.php?name=Downloads&d_op=viewdownload&cid=43
     
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  7. TriMesh

    TriMesh Site Supporter 2013-2017

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    Honestly, it shouldn't make any difference at all - the code inside the HC05 on the PS1 mainboard resets the timing for each character, so the data rate would have to be off by at least 11% to corrupt the SCEx strings. This is a clock error that's outside the worst-case spec for the chip even at supply voltage and temperature extremes (I.E. 2.5V VDD and 125 degrees C). I personally suspect that the idea there was a problem using the RC oscillator came from people that were using cheap third-party programmers that didn't preserve the factory oscillator calibration - and in this case, using the external oscillator connection will fix things because the corrupted calibration value is no longer being used.

    Personally, I don't like using the external oscillator connection for a couple of reasons:
    1) The external clock is derived from the audio master oscillator - it's 96 times the CD sampling frequency, so it comes out at 4.2236Mhz. Since the PIC has a specified clock speed of 4MHz, this represents a 5% overclock. Sure, these chips have plenty of margin, and should have no problem working, but it's still bad practice.
    2) Connecting up the clock requires you to run a wire with ~4MHz on it around an area of the board that has some very low level signals on it, and at that sort of frequency there is significant coupling of the signal even just using parasitic capacitance. An interesting experiment is to solder a wire to that clock and then route it near the RF amp chip on the board - the other end doesn't even have to be connected to anything - then monitor the eye waveform test point while playing a disc. You can see the noise pickup on the scope. For best (or worst) results, do this with a PU-18, since the long ribbon cable gives you reduced signal anyway.

    I'm not suggesting that the Mayumi code is bad, because it isn't - but the idea that it's "just better" is not as clear cut as you seem to think.
     
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  8. Kwyjib0

    Kwyjib0 Member

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    Wow, awesome info. I searched the web for a few days and the best explanation of the difference I could find was what I said earlier. I've also read claims of the MM3 chip failing to boot at times while playing imports while the Mayumi v4 chip didn't, but I don't know exactly how true those are. Whatever the case, I'm going to have to try them both out now.
     
  9. TriMesh

    TriMesh Site Supporter 2013-2017

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    I would assume that as long at the clock is correct the boot behavior of the MM3 should be identical to the Mayumi 4.0 - the stealth mode code between the two chips is extremely similar. So similar in fact that I'm pretty sure the MM3 was copied from the Mayumi code (that way around because the Mayumi V4.0 shows considerable similarities to the V2 code, which strongly suggests the Mayumi V4 was the original).
     
  10. MrMario2011

    MrMario2011 Robust Member

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    Wanted to come back here and give an update.

    Last time I commented I claimed that I was able to successfully burn a chip, never tried installing it though. After fighting a bit with my computer tonight I managed to burn off a few more and verify they all worked, they also all retained the OSSCAL values as well!

    Installed all 3 back to back to back. Now have 3 PSOne consoles (aka Slim) fitted with the USA MM3 chip :)

    The only issue I ran into outside of program initialization was one of my wires came off a point before I put a system back together, so that just resulted in my disc spinning at full speed. Resoldered the wire to the resistor it needed to be at and it worked perfectly!
     
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  11. duo_r

    duo_r Active Member

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    thanks for the guide, here is the programmer i made. Still waiting for the chips to arrive.
    [​IMG]
     
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  12. duo_r

    duo_r Active Member

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    ok so it detects my programmer but doesnt detect the PIC.

    THE PIC im using has this code:

    12F508
    I/P(e3)C2A
    1210

    the code looks a little different that the one posted but i figured since it is still a 12F508 it should work. any troubleshooting tips?
     
  13. barrybarryk

    barrybarryk Member

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    I had just done the same thing before seeing your thread.

    I already had a PICKit 3, but it can't write to a 12C508 for the OneChip hex I need here in PAL land (with a PAL PSone) but I had some 12F508 PICs handy. I was a bit paranoid about some of the configuration registers being in different places so I fed the original OneChip hex back through a disassembler, imported the assembly into Microchips MPLab X and configured the project for a 12F508 to make sure all the config bits were set correctly, compiled, flashed and it's all working perfectly.

    It might be something to keep in mind since the 12F508 is easier to get hold of, easier to flash and cheaper (though neither chip is exactly pricey).
     
  14. duo_r

    duo_r Active Member

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    Ok using multimeter I confirmed that BS170 pin D is getting 5V. Measuring pin 1 of the 12f508 I am getting -.5V, and pin 4 is getting -.5V and goes to 0 after one second. Any idea what is up? The Bs170 is a Mossfet but I believe all of them area. My wiring looks correct.
     
  15. Mord.Fustang

    Mord.Fustang Fiery Member

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    Make sure your BS170 is not reversed and you'll have to redo all your points. Hate to state the obvious but also make sure the PIC is installed in the correct orientation. :)

    Got another PC with a serial port to rule that out? Try different USB ports too, just in case one of them is underpowered.
     
  16. duo_r

    duo_r Active Member

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    Yeah BS170 not reversed and the PIC is facing the right direction. I might try a different PC.
     
  17. Mord.Fustang

    Mord.Fustang Fiery Member

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    Also, are you using PICPgm?
     
  18. duo_r

    duo_r Active Member

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    Yes I'm using PICPgm.
     
  19. ponsai

    ponsai Member

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    I recently just bought the K150 that MrMario2011 bought from Amazon, however I'm confused if this thing is actually working or not. It's not being detected by picpgm programmer at all and is only being detected by MicroBrn (another pic programmer). I've installed the drivers for this thing and I can confirm it's working in device manager.

    Whenever I read a blank 12f629 chip, all I get are 3FFFs. The guide says that the chip might not be read correctly but I can't get it to show anything else. I took the plunge and programmed a Mayumi v4 hex and I can verify its data. I have one extra chip that is also reading all 3FFFs. Any advice?
     
    Last edited: Aug 7, 2016
  20. Mord.Fustang

    Mord.Fustang Fiery Member

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    The K150 will ONLY work with MicroBrn. It won't work with PicPGM unfortunately.

    I assume the 3FFF that's being read is in MicroBrn?
     

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