Reverse-engineering a vintage comparator chip: So what is this chip? Maybe it’s simply four comparators, but they could have a specific purpose. The chip could be a converter for four differential input signals, e.g. DCS (Differential Current Switch) logic. Another chip in the family seems to be Emitter-Coupled Logic, so this chip could be four […]
Category Archives: Chips
Reverse-engineering a low-power LED flasher chip
Ken writes, “How do you make an LED blink? A vintage way is the LM3909, a chip from 1975 that can flash an LED for a year from a single flashlight battery. This chip has some surprising features, such as a charge pump that lets you power a 2-volt LED from a 1.5-volt battery. This […]
Reverse engineering RAM storage in early Texas Instruments calculator chips
Reverse engineering RAM storage in early Texas Instruments calculator chips: Texas Instruments introduced the first commercial single-chip computer in 1974, combining the CPU, RAM, ROM, and I/O into one chip. This family of 4-bit processors was called the TMS1000. A 4-bit processor now seems very limited, but it was a good match for calculators, where […]
Reverse-engineering the classic MK4116 16-kilobit DRAM chip
Ken has written an article on reverse-engineering the classic MK4116 16-kilobit DRAM chip: Back in the late 1970s, the most popular memory chip was Mostek’s MK4116, holding a whopping (for the time) 16 kilobits. It provided storage for computers such as the Apple II, TRS-80, ZX Spectrum, Commodore PET, IBM PC, and Xerox Alto as […]
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 […]
Simple DataFlash board
David Johnson writes: This is a small board that plugs into one of the headers on an Arduino Uno or other board to provide 4Mbytes of non-volatile storage It works with either 5V or 3.3V boards, and is based on the low-cost 4Mbyte Winbond W25Q32FVSIG DataFlash chip. It is ideal for applications such as data […]
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 […]
Decap a Chinese chip at home: Clone or not?
Sjaak writes, “It has been a while before I posted something useful. On my search for obscure chips, I came around another interesting Chinese chip (which I don’t reveal yet). The chip was advertised as a cheap drop-in replacement for a American IC so I suspected it would be a clone. I wanted to look […]
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 […]
STM32F103 vs GD32F103
Sjaak wrote about a Chinese ARM chip compared to a ST ARM chip: Most of us do know the ST line of ARM chips called STM32. They come in multiple flavours and the STM32F103 is one of the most common entry level family of chips. They are called by ST as mainstream. They are a […]
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 […]
BGA Reballing Practice Kit
@joegrand tweeted, “Practicing BGA reballing with the @dangerousproto BGA Reballing Practice Kit.” More resources and instructions available here. Get your own kit for $79 at Seeed.
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. […]