Extracting ROM constants from the 8087 math coprocessor’s die

Ken posted an article taking a closer look at Intel 8087 chip: Intel introduced the 8087 chip in 1980 to improve floating-point performance on the 8086 and 8088 processors, and it was used with the original IBM PC. Since early microprocessors operated only on integers, arithmetic with floating-point numbers was slow and transcendental operations such […]

Inside the Am2901: AMD’s 1970s bit-slice processor

Ken posted an article taking a closer look at AMD’s Am2901 chip: You’re probably familiar with modern processors made by Advanced Micro Devices. But AMD’s processors go back to 1975, when AMD introduced the Am2901. This chip was a type of processor called a bit-slice processor: each chip processed just 4 bits, but multiple chips […]

Looking inside a vintage Soviet TTL logic integrated circuit

Ken Shirriff examines a 1980s chip used in a Soyuz space clock: The clock is built from TTL integrated circuits, a type of digital logic that was popular in the 1970s through the 1990s because it was reliable, inexpensive, and easy to use. (If you’ve done hobbyist digital electronics, you probably know the 7400-series of […]

Looking inside a 1970s PROM chip that stores data in microscopic fuses

Ken Shirriff did teardown of a 1970s PROM chip: The MMI 5300 was a memory chip from the early 1970s, storing 1024 bits in tiny fuses.1 Unlike regular RAM chips, this was a PROM (Programmable Read-Only Memory); you programmed it once by blowing fuses and then it held that data permanently. See the full post […]

Silicon die analysis: Inside an op amp with interesting “butterfly” transistors

An excellent in-depth look at theTL084 op amp by Ken Shirriff: Some integrated circuits have very interesting dies under a microscope, like the chip below with designs that look kind of like butterflies. These patterns are special JFET input transistors that improved the chip’s performance. This chip is a Texas Instruments TL084 quad op amp and […]

Inside the 76477 space invaders sound effect chip: Digital logic implemented with I2L

Ken Shirriff has written an excellent in-depth look at the 76477 sound effects chip: The 76477 Complex Sound Generation chip (1978) provided sound effects for Space Invaders1 and many other video games. It was also a popular hobbyist chip, easy to experiment with and available at Radio Shack. I reverse-engineered the chip from die photos […]

Taito C-Chip: data by lobotomy

CAPS0ff writes: In a previous post we described some early attempts to analyze the Taito C-Chip. See Haze’s forum post for some background on the C-Chip itself. In particular we’re interested in the EPROM. Previous efforts focused on less invasive techniques with the goal of keeping the C-Chip alive after dumping. Unfortunately, we’ve been unable […]

A journey into Capcom’s CPS2 silicon – Part 2

Here’s an informative part 2 of the Capcom CPS2 reverse engineering series by Eduardo Cruz: Capcom’s Play System 2, also known as CPS2, was a new arcade platform introduced in 1993 and a firm call on bootlegging. Featuring similar but improved specs to its predecessor CPS1, the system introduced a new security architecture that gave Capcom for […]

Examining a vintage RAM chip, I find a counterfeit with an entirely different die inside

Ken Shirriff writes, “A die photo of a vintage 64-bit TTL RAM chip came up on Twitter recently, but the more I examined the photo the more puzzled I became. The chip didn’t look at all like a RAM chip or even a TTL chip, and in fact appeared partially analog. By studying the chip’s […]

A look inside the DS3231 real-time clock

Pete posted an article taking a closer look at Maxim’s DS3231 real-time clock: Fortunately, Maxim also offers the DS3231, which is advertised as an “Extremely Accurate I2C-Integrated RTC/TCXO/Crystal”. This chip has the 32kHz crystal integrated into the package itself and uses a built-in temperature sensor to periodically measure the temperature of the crystal and, by […]

Reverse engineering the 76477 “Space Invaders” sound effect chip from die photos

Ken Shirriff has written an article on reverse engineering the 76477 “Space Invaders” sound effect chip: 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 […]

Inside the vintage 74181 ALU chip: how it works and why it’s so strange

Ken Shirriff writes: The 74181 ALU (arithmetic/logic unit) chip powered many of the minicomputers of the 1970s: it provided fast 4-bit arithmetic and logic functions, and could be combined to handle larger words, making it a key part of many CPUs. But if you look at the chip more closely, there are a few mysteries. […]

74181 ALU design on Altera MAX II CPLD

Dilshan Jayakody writes: 74181 is 4-bit arithmetic and logic unit introduced by Texas Instruments in March 1970 and it is known for being the first ALU in single package. This chip is no longer in manufacturing but still it is quite popular in CA (computer architecture) courses in many colleges. To test the behavior of […]

Analog Devices AD587KN 10V reference

SteelCity Electronics published an article about Analog Devices AD587KN 10V reference: I recently got hold of an Analog Devices AD587KN high precision 10.000V reference chip. This model of chip has an output value of 10.000V ± 5mV (that is, an output value of 9.995V to 10.005V) straight out of the factory. A voltage drift of […]