in case that the GPU should output an amplified constant 53MHz test signal somewhere, then one could divide that by 12). Later consoles (PSones at least), are using an external clock divider, which does always output a constant color clock, regardless of whether the GPU is in 50Hz mode or 60Hz mode.įor modding the older PSX boards, one could use the 4pin crystal (as shown the jpg above), or one could use a 2pin crystal (which may be easier to get, but which might require some additional amplifier, the CXA-1645 datasheet may contain more info on that), or one could probably use some clock divider instead of a crystal (eg. The problem is GPU.Pin153 which seems to output 53MHz/12 in 50Hz mode (PAL color clock), and 53MHz/15 in 60Hz mode (NTSC color clock).
the part about GPU.Pin157 is just same as on later PSX models. Pin6 is SCIN color clock (normally goes to GPU.Pin153) (must be 4.43361875MHz to get intact PAL colors at both 50Hz+60Hz) Pin7 is NTSC/PAL select (normally goes to GPU.Pin157) (must be GNDed to force PAL mode at both 50Hz+60Hz) Pin1 is GND (how stupid is that? Can't they say GND instead of Pin1? grmph) Development Console: SCPH-5502 with 8MB RAM, MM3 Modchip, PAL 60 Colour Modification (for NTSC), PSIO Switch Board, DB-9 breakout headers for both RGB and Serial output and an Xplorer with CAETLA 0.34. After some reverse engineering, I found out that the four CXA-1645 pins are: Re: DOWNLOAD PlayStation 1 BIOS Collection. Instead of signal names, they are just talking about "connect the green wire" and the "to solder pad shown on the photo". The ugly thing about mods is that they are usually not telling what they are doing, and why they are doing it.
The forum where I found the above jpg stated that the QXO-1100 should be 5V, 4.433MHz (which looks quite right for a PAL mod). The missing info in the jpg is: what-the-fuck is a QXO-1100? As far as I understand, QXO-1100 is some product line that can have different frequencies and maybe also different voltages. I came across that same jpg yesterday, too.
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