Sabz5150
01-11-2011, 08:56 PM
http://research.swtch.com/2011/01/mos-6502-and-best-layout-guy-in-world.html
This is wonderful news... its been decades since anyone knew exactly how the 6502 worked its magic as the tech specs were lost. This will be a giant leap forward for NES clones.
"A team of three people—Greg James, Barry Silverman, and Brian Silverman—accumulated a bunch of 6502 chips, applied sulfuric acid to them to strip the casing and expose the actual chips, used a high-resolution photomicroscope to scan the chips, applied computer graphics techniques to build a vector representation of the chip, and finally derived from the vector form what amounts to the circuit diagram of the chip: a list of all 3,510 transistors with inputs, outputs, and what they're connected to."
I'm still amazed by the fact that the designer of the 6502 nailed it in one shot. That is unheard of.
Bil Herd summarizes the situation. “No chip worked the first time,” he states emphatically. “No chip. It took seven or nine revs [revisions], or if someone was real good they would get it in five or six.”
Normally, a large number of flaws originate from the layout design. After all, there are six layers (and six masks) that have to align with each other perfectly. Imagine designing a town with every conceivable layer of infrastructure placed one on top of another. Plumbing is the lowest layer, followed by the subway system, underground walkways, buildings, overhead walkways, and finally telephone wires. These different layers have to connect with each other perfectly; otherwise, the town will not function. The massive complexity of such a system makes it likely that human errors will creep into the design.
After fabricating a run of chips and probing them, the layout engineers usually have to make changes to their original design and the process repeats from the Rubylith down. “Each run is a couple of hundred thousand [dollars],” says Herd.
Implausibly, the engineers detected no errors in [Bill] Mensch's layout. “He built seven different chips without ever having an error,” says Peddle with disbelief in his voice. “Almost all done by hand. When I tell people that, they don't believe me, but it's true. This guy is a unique person. He is the best layout guy in the world.”
This is wonderful news... its been decades since anyone knew exactly how the 6502 worked its magic as the tech specs were lost. This will be a giant leap forward for NES clones.
"A team of three people—Greg James, Barry Silverman, and Brian Silverman—accumulated a bunch of 6502 chips, applied sulfuric acid to them to strip the casing and expose the actual chips, used a high-resolution photomicroscope to scan the chips, applied computer graphics techniques to build a vector representation of the chip, and finally derived from the vector form what amounts to the circuit diagram of the chip: a list of all 3,510 transistors with inputs, outputs, and what they're connected to."
I'm still amazed by the fact that the designer of the 6502 nailed it in one shot. That is unheard of.
Bil Herd summarizes the situation. “No chip worked the first time,” he states emphatically. “No chip. It took seven or nine revs [revisions], or if someone was real good they would get it in five or six.”
Normally, a large number of flaws originate from the layout design. After all, there are six layers (and six masks) that have to align with each other perfectly. Imagine designing a town with every conceivable layer of infrastructure placed one on top of another. Plumbing is the lowest layer, followed by the subway system, underground walkways, buildings, overhead walkways, and finally telephone wires. These different layers have to connect with each other perfectly; otherwise, the town will not function. The massive complexity of such a system makes it likely that human errors will creep into the design.
After fabricating a run of chips and probing them, the layout engineers usually have to make changes to their original design and the process repeats from the Rubylith down. “Each run is a couple of hundred thousand [dollars],” says Herd.
Implausibly, the engineers detected no errors in [Bill] Mensch's layout. “He built seven different chips without ever having an error,” says Peddle with disbelief in his voice. “Almost all done by hand. When I tell people that, they don't believe me, but it's true. This guy is a unique person. He is the best layout guy in the world.”