I've been hacking on an Apple ][ over the past few weeks. It runs on a 6502 processor. It's kind of mind-blowing to know that the thing used to run an entire PC was later used for pocket toys like the Tamagotchi a handful of years later. The speed at which technology has improved will never cease to amaze me.
> It's kind of mind-blowing to know that the thing used to run an entire PC was later used for pocket toys like the Tamagotchi a handful of years later.
Perhaps ironically, all of the microprocessors of the early and mid 1970s, the 6502 included, were intended as embedded controllers. Systems where you couldn't justify the expense of a "real" computer, and didn't want to design full custom electronics. Like for an engine control unit, or, indeed, a video game. (Although not for handheld battery-powered units originally, only the later CMOS revisions had low enough power draw for that to be practical.)
That hobbyists would make single-board computers with about the capability of an early 1960s minicomputer using chips like the 6502 or 8080 - and then find those machines useful enough to create a large market - was quite a surprise, and an upset, to both the semiconductor and computer manufacturing companies. MOS was one of the first to recognize that market, and sell direct via mail order. The easy availability of samples, and low cost in small quantities, was one of the reasons for the 6502's success against its bigger competitors. Motorola, Intel, TI, etc. at the time were marketing to the engineers at companies that made car engines, CNC machines, telephone exchanges, etc.
Some 'window-shopping' at a smart card retailer shows a mixture of Atmel, ARM and unspecified RISC processors in use. That would suggest to me that they not only have different instruction sets, but are much more capable than the 6502. I certainly wouldn't choose a 6502 on which to run my Java applets!
> […] The image pointer table was in page 14. Pages 19-21 contain mysterious data which could be compressed audio, or could be the Tamagotchi’s soul. It’s hard to tell.
Then there is the Tamagotchi Singularity inspired by an XKCD comic [1]. It is a server full of emulated tamagotchis [2] that interact with each other in a simulator, all running code dumped by Natalie's technique. I'm impressed by both these hacks, especially the combination.
I recognized the presenter's name - Natalie Silvanovich - and sure enough, she's a member of Project Zero, and I've read posts by her before. I guess Tamagochis were her gateway drug into reversing!
Nice talk! Travis Goodspeed, who she mentions helped her decapping the chip, has some very interesting reverse engineering talks, e.g. a tear-down of a commercial glucose monitor:
> Let's consider your proposed 8086 done in a 14 nm process. Let's say we do it in CMOS, and maybe even throw in a few extra features, and it takes 100,000 transistors. The die would be very tiny, so unbelievably tiny. You could fit three thousand of them, with room to spare, in a single square millimetre, which is an area likely smaller than the period at the end of this sentence.
Sure but 8051 is probably the most widely manufactured processor in human history (along their clones and derivatives) and they were originally fabbed using a 3.5 µm (3500 nm) NMOS process (IIRC). What I'd like to know is what the most advanced process/node has been used to manufacture a production 6502, Z80, or 8051 (or other old standard). Has anyone ever fabbed any of the those CPUs/MCUs at 130 nm or better?
Though, I will say that I'm amazed that anyone is still mass producing digital products on a 6" (if not smaller) wafer using a node that was invented in the mid 1970s (300 mm wafers are the current standard with the next proposed step being 450 mm). I mention digital because a lot of analog gear (and I think some MEMS) is fabbed using what most of us would consider ancient process nodes.
As somebody who's terrified of speaking on front of a group, I liked that the presenter is visibly nervous but also having a good time giving her talk. Also, she does a great great job of explaining her steps in a way somebody who has never done any kind of reverse engineering (that would be me) can understand.
I watched this one in 2012, although not live. There is a follow-up talk she gave one or two years later, "Many more Tamagotchis were harmed in the making of this presentation" that is equally enjoyable.
You tore apart their innards and proudly placed their ravaged shells on display for the world to see. To us, they were our children. To you, they were an object of torment for your children.
https://natashenka.ca/tamagotchi-friends-code-dump/#more-281