PSNee further development

General information to do with the PlayStation 1 Hardware. Including modchips, pinouts, rare or obscure development equipment, etc.
Curious PSXDEV User
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Re: PSNee further development

Post by postal2201 » April 15th, 2019, 4:16 am

rama3 , I meant to replace the built-in functions with direct control of ports, and macros. Do not give up on Arduino. On the contrary, the use of Attiny limits the project.

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Re: PSNee further development

Post by rama3 » April 15th, 2019, 5:52 am

Search this forum or Google for PSX color oscillator mod. This is what your board needs.
But it is a difficult mod and the result looks pretty bad. I recommend you use a later revision PSX.

The code uses direct port control where speed is required, and can use Arduino functions when not.
Arduino functions are inherently more safe, so using them for non-critical tasks is good.

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Re: PSNee further development

Post by pewu » June 7th, 2019, 7:53 am

I have a PU-20 NTSC-J frankenstein console with non-NTSC-J bios soldered in place of original, for the purpose of installing this modchip. Unfortunately, PSone PAL was the only chip I could salvage right now. I used Pro Mini clone (Atmega328P) Physical installation went smoothly and PAL games booted just fine, meaning injection worked straight out of the box.

The real ordeal began, when I tried to enable NTSC_fix, so that PSone bios can be patched and boot all region games. At one point it turned out, that when I apply external 3.3V from FTDI board or Raspberry to RX pin on Arduino, BIOS patching code works fine (weird)...

I tried many combination of fuses, to no avail, until I started thinking more logically, and just increased the first delay in NTSC_fix routine to 500 ms. With such setup I tested booting several times, with originals and with backups of those - modchip works flawlessly. My final fuse setup is (E:06, H:DF, L:C2).

Tomorrow I'm going to look for 3.5V source that is drained after reset button press (after all, PSones never had a reset btn, so that was non-issue), but otherwise I finally managed to mod my frankenstein.

Maybe this will save somebody some headache next time.

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