Ask Slashdot: Understanding the SNES?

An anonymous reader writes "As a product of the 90s I grew up loving the classics that kids today know about from Wikipedia and pop-culture references. Games like Super Bomberman, Zelda: A Link to the Past, Donkey Kong Country I and III (II was a sellout, come on) are the foundations of my childhood memories. Now, though, as a fourth-year electrical engineering major, I find myself increasingly impressed by the level of technical difficulty embedded in that 16-bit console. I am trying, now, to find a resource that will take me through the technical design of the SNES (memory layout, processor information, cartridge pin layouts/documentation) to get a better understanding of what I naively enjoyed 15 some years ago. I am reaching out to the vast resources available from the minds of the Slashdot community. Any guide/blog series that you know of that walks through some of the technical aspects of the, preferably, SNES (alternatively, NES/Nintendo 64) console would be much appreciated."

Re:It's a great design

[JDG1980]

Especially interesting is the special circuitry that eliminated the need to blow air into the cartridges that plagued the original NES.

The need to blow air into cartridges on the original NES was a result of DRM.

No, seriously.

The NES console contained a chip called the CIC [nesdev.com], which had to perform a handshake with a corresponding CIC on the cartridge, or else the system wouldn't boot (and you'd get that blinking red power LED). The purpose of this was to ensure that no one could manufacture NES cartridges without the approval of Nintendo of America. Unfortunately, it also made the boot process far more finicky; even the slightest amount of dirt would cause the handshake to fail and the system to repeatedly reset. (The fact that Nintendo used a weird ZIF-style connector rather than a standard card edge connector didn't help, either. This was done because they didn't want the NES to look like a standard game console, which had a bad reputation after the 1983 crash.)

Re:take one apart?

[mk1004]

I'm an ME, so I don't know much about reverse engineering electronics. maybe this will help? http://s3cu14r.wordpress.com/2010/07/15/boiling-chips-in-tree-sap/ [wordpress.com]

I use to occasionally decap 'plastic' ICs, which are typically molded using an epoxy based compound. We always used fuming nitric to open those. We used a dropper to put the heated nitric on the top of the package, the goal being to have the pins intact and the device functional afterwards. Not real safe unless you have the proper equipment and know what you are doing. Later we had commercial equipment that did pretty much the same thing.

I suspect the rosin used in the link only works on some types of non-epoxy based plastics.

Re:CIC failure vs. PRG failure

[_133MHz]

I was able to distinguish between the game not booting and the system reset being held low by the CIC back in the day, apparently no sync is generated during reset or something along those lines because even though you get a black screen you can see it "free-running" and getting torn up horizontally, and newer TVs just blank out the video entirely like an invalid signal. I was even able to hear the difference by 'feeling' if the horizontal oscillator on the TV was free-running or locked. With a successful CIC handshake but bad program execution you get a black screen with proper sync which overrides video blanking on newer TV sets.

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