Ah, yeah. I guess what I thought would have been too easy or someone would have done it already. But wouldn't it be possible to program a chip to do something like that? Exactly like the other modchips work by making it believe it's running a licensed game.
Anyways, thank you for a fast reply!
I'm unsure of how the N64 CIC works, the SNES and NES systems worked by just checking for a signal and then making a pin go from high to low which enabled the CPU. The N64 version could make use of cyphers and encryption or whatnot, so you'd either need to find out how the chip worked or get the schematics for it.
On boot, the PIF inside the n64 starts sending a very, very long sequence of random numbers to the CIC. The PIF is always reading the response back (this is a continuous process while the N64 is turned on).
Once the PIF is happy with the values it's getting back, it releases NMI on the R4300. This causes an NMI interrupt on the cpu, and causes it to start executing code from the memory location 0xBFC00000. Because all the memory is accessed through the RCP, this small segment of memory is mapped to a small almost 2k chunk of ROM in the PIF called PIF-rom.
The code in there is r4300 executable code. The actual boot process is pretty convoluted, that's another time. But about halfway through the sequence of boot programs, the R4300 reads from PIF ram (small 64byte area) and this contains values used in the calculation of the CIC seed. (6102 seed is 0x3f)
The way a game determines whether it's running on a PAL or NTSC console is simple - it's hardcoded in the PIF rom.
If you have a logic analyzer and some tools you can put probes on the lines that go from the PIF to the RCP and catch all the contents of the pif ROM as it's read. This is the only way to get access to it, because after the boot process you will read all 0's from where the PIFrom used to be mapped.
Once you have it dumped you can look for the instruction that loads the register s4 (something like li s4, 0x01) and change it to 0x0 for PAL, and 0x1 for NTSC.
You can also use a boot emulator to do all this, but it means you have to have a way of running your own code. The boot emulator basically runs a version of PIFrom that is hacked to skip the security checks, and you patch in whatever values you want (you can fake different CICs and regions this way)
The CIC seed is also used to checksum the bootcode in the first 4k of game ROM, and to also checksum the first 1MB transferred to make sure the cart interface is reliable.
Last edited by marshallh; 07-05-2010 at 12:09 PM.
how about useing seb code switchless mod useing the reset buttion would be cool
Now i do not like that you need 5 switches (ore even more) to do this
so why not just make the 2 different PIF-NUS chips in like a little cartridge
that you can change out if you want to play a game from another region
Did this in google sketchup for fun::thumbsup: (just need a case for it)
now will this work or did i do something really wrong?
There seems to be a misunderstanding - You don't use separate switches for each one in the diagram, you only need a single one that switches five contacts at once.
Can't see why your idea shouldn't work though, but it'd be a helluva lot of very unnecessary work, and probably with pretty ugly-looking results imho.
Two MC14551B ic's and 1 spdt switch then ?
what about running ntsc game on a pal console using passport III. Will it be 60 hz?
Last edited by mca; 03-06-2011 at 06:57 PM.
Why not a switchless mod via reset?
Here's a picture of the inside of my N64. I bought it already modded with the region switch from http://www.otakus-store.com/. They sell a lot of modded consoles and also do a lot of modifications so maybe they know how this mod was done. It works 100% for all games, even PAL Perfect Dark works perfectly.
As far as I'm aware the refresh rate is determined by software settings so NTSC games should run at 60 hz. If you load an NTSC game on a PAL console with an Everdrive or other backup device they run at 60hz. Some games will have audio errors because your using the wrong PIF chip.Originally Posted by mca
Does the refresh rate change too? I'd be very interested to know how it was done if so!Here's a picture of the inside of my N64. I bought it already modded with the region switch from http://www.otakus-store.com/. They sell a lot of modded consoles and also do a lot of modifications so maybe they know how this mod was done. It works 100% for all games, even PAL Perfect Dark works perfectly.
Region is set via a very complex method that isnt cracked (i.e. a replacement chip, like the supercic). You would need a way to give both types of PIF responses to the console. Which is why people are installing both chips.
Now you could install both chips, install some solid state switching and then control them via a switchless mod, but its no where near as simple as you are making it sound.
That looks a lot nicer than the mess inside my N64:
P1000316.JPG
Last edited by marqs; 08-31-2012 at 12:45 PM.
I asked this in another thread similar to this one.
What is the thought of installing the "key" from a game into the console permamently? IE disable the cart lines.
It would be similar/same as using one of those piggy back adaptor carts.
I was going to attempt this, I have both PAL and NTSC boards, but I was going to try and make one of the PAL boards region free.
Reading this makes me believe it is easier just to set up both types of consoles lol!
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