Why we can't just copy the PC-10 PPU RC2C03B

Gaetznes

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I don't have the answer, only a few things I can guess. I remember reading a while back that you can not copy/reproduce the playchoice 10 ppu. This had more to do with the RGB mod for the NES. For the life of me I can't find this site or fourm I read this in. Since then i've become intrested in all things Playchoice 10. Through this I've been reading up on Eprom EEprom, Mask Rom, differnces between Microprocessors and a number of other things.

By no means am I stating that I understood everything i've read. At no point do I claim to be right, in what i'm going to say. I might even be spewing information the average programmer considers common knowledge. Just want a discussion with those that know better then I, on this subject. Hopfully, this will help others on their way.

So beyond the fact that the PPU is an IC or defined as a Microcontroller/processor, its a Rom of some sort, Right? I'm assuming it would be a Mask rom or a OTP Rom. As I can only assume that they didn't want people going into it and messing with the program. However, that still doesn't tell us why we can't copy it.

To date there is only two thing i've read that would prevent someone from coping the information. First being, that some type of fuse on the chip can be blown. This allows the chip to function, but prevents access to all the data on the Rom. The fuse can be reset, however this is done by using UV light which would wipe the data.

The second is a encryption of the data on the chip itself.

My curiosity would be, does everything lay with the programming. Does the architecture of the chip itself play a role in the reason it can't be reproduced? If say the data was easily retrieved, is it possible for someone to reproduce the chip?
 
Uhh.. How can an MCU be a ROM? If it wasn't possible to access the data from a ROM, how could the game hardware read it?

Does the architecture of the chip itself play a role in the reason it can't be reproduced?
It can be reproduced, but the costs of decapping, reverse engineering and reproducing it would be in the hundreds of thousands of dollars.

One possibility would be to obtain the source code from one of the several FPGA NES implementations and extract the PPU part out of it. You could then make up adapter boards which would allow the FPGA to drop into the PPU socket.

If say the data was easily retrieved, is it possible for someone to reproduce the chip?
There's no data stored on it.
 
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"A microcontroller unit (MCU) is a single chip that contains a processor, RAM, ROM, clock and I/O control unit. Hundreds of millions of MCUs are used in myriad devices ranging from automobiles to action figures"
http://en.wikipedia.org/wiki/Mcu

I did not state, the game hardware couldn't read the data. Just that their have been steps taken to prevent tampering. Some of those steps i've already listed.
Source:
http://www.break-ic.com/topics/break-ic.asp


Thanks for the EDIT Hewitson. Thats made it alot easier to understand what you were trying to convey.
Yes, I remember coming across this (FPGA Nes) when reading up on the nes ppu.

So your idea is that coping the ppu is unpractial due to the enormous expense. Which would go into potentially hundreds of thousands of dollars. However, your idea about using the FPGA as your source for substitution for the PPU intrigs me.
 
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"A microcontroller unit (MCU) is a single chip that contains a processor, RAM, ROM, clock and I/O control unit. Hundreds of millions of MCUs are used in myriad devices ranging from automobiles to action figures"
http://en.wikipedia.org/wiki/Mcu
Ah, I see where the confusion is coming from now. That is a poor description, it is written from a purely modern perspective.

Gaetznes said:
I did not state, the game hardware couldn't read the data. Just that their have been steps taken to prevent tampering. Some of those steps i've already listed.
Source:
http://www.break-ic.com/topics/break-ic.asp
Yes, modern MCU's do have fuse bits that can prevent people from reading the data using conventional methods. But the chip we are talking about is 30 years old, they didn't have any onboard memory back then.
 
Well atleast I can laught at myself, plus I learned something new.

Is this the FPGA Nes you were talking about?
http://danstrother.com/fpga-nes/

I only ask, because if their were a way to reproduce the PPU siginal on a daughterboard. Potentially hundreds if not thousands of PC-10 mainboards could be saved from being scavenged for RGB Nes Mods. Or best yet, perviously cambilized PC-10 mainboards could be brought back from the dead.
 
That's the one I'd be most interested in using, yes. The source code hasn't been released yet, but he says it will be done in the future. When that happens, I wouldn't mind getting myself a cheap dev kit and giving it a go. I have not worked with FPGA's for several years but I think that this should be a relatively simple project.
 
As a person that currently does not have the skills to work with a dev kit. I think I may try to bounce a few idea off him. See if the ideas that have been made here can be implemented as a finished product. Plug and Play in a way.
 
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