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Home brewed modchip

orta - Aug 15, 2004

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		patroclus02		Aug 17, 2004
			send it to patroclus02@hotmail.com... thanks By the way, where do you get the ribbon cables and conectors?? I find them no where.

		MrSporty		Aug 17, 2004
			Ribbons and connectors i "borrowed" from old modchips and saturns .. your right , you cant find them anywhere.

		patroclus02		Aug 17, 2004
			that will be a problem if we finally manage to get a way to build modchips.. by the way I'm so impatient to see those PDF. Where did they come from?? Oh, one more thing. To do a logic analisys of modchip working, do you need a special hardware, or could I just use my PC parallel port??

		patroclus02		Aug 17, 2004
			Just sended you an email

ExCyber

Aug 17, 2004

	
	
		
		
			To do a logic analisys of modchip working, do you need a special hardware, or could I just use my PC parallel port??

I think the parallel port is too slow to be used alone. IIRC it maxes out at around 2MSPS (under ideal conditions) and the CD interface runs at something like 8MHz.

edit: there might be some way to use DSO-style techniques to capture some of the signal, but as soon as anything depends on the physical timing of the drive mechanisms your timing model would probably be shot...

		patroclus02		Aug 18, 2004
			What are DSO-style techniques?? (I might know what it is, but not as DSO. sorry, english is not my first language). The problem is that logic analyzers are very expensive..

		MrSporty		Aug 18, 2004
			DSO - Digital Sampling Oscilloscope. A scope with sample and hold capabilities. Way off budget for most of us i would imagine unless your employment or educational facility brought you into contact with one.

		ExCyber		Aug 18, 2004
			I was referring to the ability of DSOs to examine a regular waveform with a frequency much higher than their raw sampling rate by phase-shifting the sample timing and reconstructing the waveform. Identical techniques obviously would not work for sampling the CD bus since it is not a regular waveform, but I thought it might be possible to pin down the timing well enough to take multiple samples over several runs. It was just kind of a random idea, I don't know if anyone's implemented anything like it.

		patroclus02		Aug 18, 2004
			Good idea but I don't know if I could do it ...

		orta		Aug 18, 2004
			ONE WORD: Sega saturn and its modchip is one tough SOB to decode and to homebrew

		mal		Aug 19, 2004
			That's not one word. :lol:

		Pyrite		Aug 19, 2004
			LOL Even so some HK pirates living in a basement figured it out and made them.

		MrSporty		Aug 19, 2004
			Neither is it a very encouraging set of more than one word TBH the mod isn't that hard to R.E. There is no complex crypto involved and the timing isn't particularly high speed or sensitive. The real reasons no one has dont it before is either lack of interest or lack of financial motivation.

		patroclus02		Aug 19, 2004
			Also, some people are specialized in programing/reading PICs and EEPROMS, etc.. They might be able to read the modchip's PIC. Here in Spain I found some, but they do not guarantee anything.. MrSporty, do you know at what frequency (bit rate) do serial MCU lines work?? (at what rate its clock line works). And data stream ?? I need to know this in order to see if I can build a suitable logic analyzer...

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