jm + chips + history   3

Reverse engineering the 76477 "Space Invaders" sound effect chip from die photos
Now _this_ is reversing:
Remember the old video game Space Invaders? Some of its sound effects were provided by a chip called the 76477 Complex Sound Generation chip. While the sound effects1 produced by this 1978 chip seem primitive today, it was used in many video games, pinball games. But what's inside this chip and how does it work internally? By reverse-engineering the chip from die photos, we can find out. (Photos courtesy of Sean Riddle.) In this article, I explain how the analog circuits of this chip works and show how the hundreds of transistors on the silicon die form the circuits of this complex chip.
space-invaders  games  history  reverse-engineering  chips  analog  sound-effects 
may 2017 by jm
Reversing Sinclair's amazing 1974 calculator hack - half the ROM of the HP-35
Amazing reverse engineering.
In a hotel room in Texas, Clive Sinclair had a big problem. He wanted to sell a cheap scientific calculator that would grab the market from expensive calculators such as the popular HP-35. Hewlett-Packard had taken two years, 20 engineers, and a million dollars to design the HP-35, which used 5 complex chips and sold for $395. Sinclair's partnership with calculator manufacturer Bowmar had gone nowhere. Now Texas Instruments offered him an inexpensive calculator chip that could barely do four-function math. Could he use this chip to build a $100 scientific calculator?
Texas Instruments' engineers said this was impossible - their chip only had 3 storage registers, no subroutine calls, and no storage for constants such as π. The ROM storage in the calculator held only 320 instructions, just enough for basic arithmetic. How could they possibly squeeze any scientific functions into this chip?

Fortunately Clive Sinclair, head of Sinclair Radionics, had a secret weapon - programming whiz and math PhD Nigel Searle. In a few days in Texas, they came up with new algorithms and wrote the code for the world's first single-chip scientific calculator, somehow programming sine, cosine, tangent, arcsine, arccos, arctan, log, and exponentiation into the chip. The engineers at Texas Instruments were amazed.

How did they do it? Up until now it's been a mystery. But through reverse engineering, I've determined the exact algorithms and implemented a simulator that runs the calculator's actual code. The reverse-engineered code along with my detailed comments is in the window below.
reversing  reverse-engineering  history  calculators  sinclair  ti  hp  chips  silicon  hacks 
august 2013 by jm
Ivan Beshoff, Last Survivor Of Mutiny on the Potemkin, founded Beshoffs
wow. there's a factoid! the "Beshoffs" chain of chippers in Dublin were founded by this historic figure, who died in 1987
factoids  beshoffs  chips  dublin  history  small-world  battleship-potemkin  russia 
january 2013 by jm

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