Has any research been done on the various jumper points on the N64? From the French console: The position & amount of jumper points vary between regions/revisions, my European has 6, there's 3 on the French model, and I have a Japanese one with none.
I did some testing on these jumpers positions years ago looking for a 50/60Hz switch mod, but eventually realised its pointless because on the N64 the hertz rate is controlled entirely by the games region setting. One set of jumper points sets the video encoder chip to output either NTSC or PAL - but this is nothing to do with the hertz rate and is simply selecting the color encoding output to one or the other, assuming the corresponding crystal oscillator is fitted. The other jumper points are to set the clock generator to NTSC or PAL frequencies for the audio, and the color subcarrier, once again this relies on the correct crystal oscillator being fitted. Also you cant switch one without the other being switched as well, otherwise you get a blank screen etc. I hope that answers your question?
Thanks link, that pretty much explains it. I traced JP1 on the French N64 to the MX8330MC, and wondered if it was possible to tweak the RAM performance. If the ability to set the colour encoding via a jumper/crystal is present on some revisions, does this mean that at some stage Nintendo intended to have a 'universal' board which could be set to NTSC/PAL during manufacture?
IIRC the RDRAM has a seperate clock signal, it might be possible to tweak it as you suggest but I dont think it would be of any benefit to standard games? I remember reading a forum thread years ago that said there was a way to overclock the RCP, which sounded interesting! Unfortunately I dont think there was any details on how to do it, and they also said that if it was performed you would lose all video output as the video clock signal would be wrong, but considering that the N64's video data format is now well understood it might be possible to use a CPLD to 'make' a new clock signal that would work :shrug: You may find this N64 block diagram interesting, its from Nintendo's patents and I 'joined' the images together as best I could:- I really dont know why Nintendo added these jumper points to the PAL motherboards - they are not present on the NTSC motherboards, so I doubt Nintendo ever planned to make a 'universal' motherboard (I wish they had!) Its especially odd since the PAL motherboards appear to have been designed about a year after the first NTSC motherboards, and Nintendo usually remove any unnecessary stuff, not add it. If it was the other way around and it was an NTSC motherboard with jumpers I could understand it, as this would be useful for countries like Brazil that use PAL-M (PAL color encoding, but 60Hz):- http://en.wikipedia.org/wiki/PAL-M But since the jumpers are on a PAL motherboard they really dont seem to make much sense :banghead: <EDIT> Is there any country which gets PAL games but also uses NTSC color encoding?
Bottom left, clock generator. Looks like the same circuit used in the datasheet for the CXA1645. If you swapped that crystal out you'd change the clock rate for everything if I'm reading it correctly. RD-RAM clock, CPU, RCP, video encoder, and DAC at minimum. The RD-RAM, CPU, video encoder and DAC get treated by different lines but the CPU passes the clock along to the RCP though "Master Clock". You might be able to hijack just 1 of the lines going from the clock generator and supplant your own clock rate to that one item. Though the N64 CPU does have pins to adjust multipliers which leads me to believe that the clock generator is for a FSB of sorts for some of the devices. The video encoder directly labels the incoming clock rate "SCIN" for sync usage. The odd part is that the clock generator is using a frequency well above what would normally be used for PAL or NTSC. Must be something with the fact that the different devices get treated differently.
The block diagram doesn't tell the whole picture - it just gives you a rough idea of how the system works. There are actually two clock generator chips on the N64 (Two MX8330MC on most revisions, eventually replaced by one MX8350MC dual clock generator on later revisions) and two crystal oscillators as well. Only one of the clock generators is switched using these jumpers and this seems to alter the audio timing, as well as the color subcarrier frequency (SCIN) for the video encoder (Hence both sets of jumpers needing to be switched together) If you read the MX8330MC datasheet it should explain alot:- http://www.datasheetarchive.com/indexdl/Datasheet-018/DSA00306828.pdf (The site seems to have added annoying 'captchas' now )
That datasheet did confirm what I had suspected in that there was some division going on as well as separate frequency outputs for different purposes.
Nice diagram, makes things look a lot clearer. As for the clock generators, a Euro N64 I have has an MX8330MC in position U5, and an MX9911MC in U7. The datasheet says it's a video clock generator as opposed to rambus clock generator.
