Playstation PSXPIC chip hack
How the hell does this chip work then?
Once installed in your PSX this neat little hack allows you to boot any disk it doesn't care whether its Jap, US or Europe, basically it allows your Playstation to become universal. As a side effect of being 'Universal' the modified machine will unfortunately also boot copies. No way do I condone the use of copies always buy the original. The main purpose of the chips is to allow you play imports.
The chip that is being used for the modification is a Peripheral Interface Controller by MICROCHIP the device is a PIC16C54, hereafter Known as the 'PIC'. The PIC contains some special code that defeats the PSX protection, without this code the PIC is about as usefull as a blank CDr. If you want the specs or data sheets on the this type of microcontroller (PLD) you should consult the Microchip Technology Incorporated. web pages.
As a far as I know these chips can't be read once the fuses have been set. The suppliers of the chip go as far as removing the top quarter of the chip as a further form of protection, this means you don't have access to pins 1 + 2 and pins 17 + 18 this seems a bit over the top, the fused protection should be enough, they also sand off the chip number so that it can't readily be identified (paranoia or what!). All of this makes it quite difficult in finding out exactly how the chip works. So basically if you buy a chip from me don't bother trying to reverse engineer it as I've already tried it, its close to impossible.
The first clue as to what type of chip being used was the fact that pins matched exactly those of the PIC family of microcontrollers, I assumed that the device could only be a 16c84 or 16c54. The 16c54 seemed favorite as this device is OTP (once programmable only) and is therefore cheaper, the 16c84 is a bit more expensive as its EPROM area can be erased and used again. Anyway this has been confirmed now because the chips I can supply have the Identification still on them.
Those of you (me included) who originally thought the chip was a simple logic circuit don't know how wrong you where. The device actually contains code that detects a system reset, or door closing switch and outputs data to the cdrom control section of the PSX to fool the protection schemes. The first clue that confirms the chip doing something more than simple logic is the fact that it is being clocked.
Heres a bit of technical theory for all you electronics guru types.
The first thing that happens upon a system reset is the PIC counts a number of clock pulses after which it synchronized with the playstation CD subsystem.
Next the PSX checks its own firmware to see what territory it belongs in. This data is then passed to the 80/52QFP chip it seems that this data is also read by the pic which then probably stores a value in a register which represents the territory data read from firmware ie. a=JAP b=UK a=US. So then when the actual territory sectors are read from the CD, the pic intercepts this data and replaces it with data stored in its own rom which represents either JAP, US or UK this depends on what it has stored in that register I mentioned earlier a b or c.
I'll add more here as soon as I get something worth adding..
Install
Installing your PSXPIC modification.
Tools and the obvious things you will need.
- A half decent Philips or Posidrive No.1 Screwdriver.
- A Soldering Iron that has a tip that is good for fine soldering, don't use a tip thats the size of a spade.
- A few centimetres of solder, use finer than (1mm) 18 SWG if possible.
- A bit of patience and a steady wrist.
- It also helps if you can see what you are doing, sorry the instructions aren't available in braile.
I don't like re-inventing the wheel so bits of the following instructions have been borrowed from other documents available all over the net. If anyone recognises a bit of text that they are not too happy about being here let me know and I will remove it.
Firstly disconnect the PSX from the mains, there are dangerous voltages within the PSX, Remember I want you to live to test out your newly modified PSX. I would go as far as saying leave it unplugged from the mains for about 5 mins before taking the lid off. There are voltages present in the power supply area for a couple of minutes until the large capacitor in the power supply has discharged.
Removal of the PSX cover
- Turn unit over and remove the 5 screws.
- Turn unit right-side up, and lift the cover off.
Removal of the laser housing
- Disconnect the ribbon cable by pulling straight up on the black connector. This will release the cable, which can then be removed, by pulling straight up. Do this very carefully if you damage this carbon cable you will need a new laser unit, last I heard these don't come cheap.
- Gently disconnect green connector (3 grey + 1 white wire) by pulling straight up.
- Disconnect collection of rainbow colored wires by pulling straight up.
- Lift off laser housing.
Removal of the controller/memory card housing
- Remove the 5 screws holding the thin metal bracket in place.
- Lift off the bracket.
- Disconnect the ribbon cable by pulling straight up.
- Lift off the controller/memory card housing.
Removal of the heavy metal bracket
- Remove the 5 screws holding the bracket in place.
- Lift off the bracket. Also peel back any copper screening.
Removal of the circuit board
- Remove the 3 screws along the top edge.
- Lift off the circuit board.
Right once you have got to this stage you are ready to install the chip. The first thing to do is to solder the wires to the chip holder, once you have done this you can begin to solder the wires around the underside of the PSX main board.
Decide which type of board matches yours out of the following types then solder the wires to the points shown.The main difference between the 2 types of PSX board are the type of chip it has in the top right hand position under the board. This chip is either a 52 pin or 80 pin device. Most of the connections to the mod remain the same for both types but there are a few differences.
Instructions and JPG's
These have been included in these pages with the kind permission of Scott Johnson. The numbers on the arrows represent which pin on the PSXPIC that point needs to be connected to.
For more installation pictures take a look at the PCB layouts page
Once you have soldered all the points and double checked to make sure you have done it right you will need to reassemble your PSX. Before you do this insulate your chip with electrical insulating tape. Under No circumstances glue the chip to the underside of the board as others have suggested. Simply make sure it is insulated adequatley (ie. so that you can't see any pins or bare wire) then route the cables thought/past the right hand side of the metal sheild before you screw it back in place. During reassembly make sure you do not trap any of the wires going to the PSXPIC between screws etc..
Next Plug and Play.
Circuit Board Layouts.
The following are pictures taken by me of the most common model in the UK (& europe) this is the board in the SCHP1002 models. The board type is the one that uses the 80pin qfp chip. Please view these with a true colour (16million colour) video setup for optimum results.
I have not included a close up for the ground pin because this is easy to see on the full picture.
Other Pictures
These JPGS are varios PCB layouts that I have collected, they are mostly wired the same, I put these here mainly for people with JAP machines whos boards are a little different from the usual UK boards, the quality variable (don't blame me I did not scan these).
