July 2nd, 2017 ~ by admin

ITT AN/ALQ-136 Countermeasures Processor – Bit Slice with a Bite

ITT 80063SM-A-919797 – AN/ALQ-136(V)I Processor. The 2901B’s are the 4 larger dies in a row, middle right.

Military computing applications require many custom designs, as they are very mission specific.  A great example is this ITT hybrid processor.  It was designed and used for the AN/ALQ-136(V)1 CMS (CounterMeasures System) for the AH-1F Cobra Attack helicopter.  Two of these hybrids are used in the system, one for the Mod Recovery board, and one for the SLO processor board.  These boards are used to detect hostile pulse RADAR systems, analyze them, and begin jamming based on what type they are.

This requires relatively fast processing, and a generally custom design.  Today a modern DSP processor could handle this task without issue.  However in the early 80’s (the AN/ALQ-136 debuted in 1982) DSP processors were in their infancy.  In 1982 a fast custom processor needed to be built with bit-slice elements.  In this case the very versatile AMD 2901 was used.  The ITT hybrid integrates 4 AMD AM2901B processor dies, as well as associated memory and interfacing elements.  The single package contains almost 100 dies, and many discrete components.  It is built on a ceramic substrate with gold traces, and sealed in a metal package.  This is required to protect the digital components of the system from electronic interference, whether from external sources, or from the helicopters own RADAR systems.  The AN/ALQ-136 is designed to prevent the Cobra from being successfully targeted by RADAR guided missiles, failure means a strong possibility that the helicopter gets hit, not something its crew would like to deal with.

4x AMD AM2901B Dies.

The 4 AMD 2901Bs run at 16MHz (50% faster then the original 2901s) and are made with ECL; together they provide 16-bit processing of the incoming RADAR signals. The SLO (Side Lobe Opposition) and MOD Recovery (Modulation Recovery) are used to determine the exact type of the enemy RADAR.  Each RADAR has a distinct characteristic that the CMS can match and respond to.  The CMS is programmed to respond to the radar signals of the most critical threat weapon systems anticipated to be encoun

Israeli AH-1F Cobras – Now Retired/Transferred to Jordan.

tered in the hostile environment.  These signatures are stored in the hybrids ROMs as well as the desired response to them.  Updates likely remain replacing these hybrids with updated versions.  New countermeasures systems (such as the 136’s replacement, the AN/ALQ-211) are more easily upgradeable to new threats.

The AH-1F Cobra continues to fly with the air forces of several countries around the world, notably Pakistan, Jordan, and Turkey.  The United States Forest Service also operates 25 AH-1F Cobras for wildland fire use, but it is rather unlikely that the countermeasures on these are operable, let alone needed.

October 8th, 2015 ~ by admin

AMD 20 Processor Test Board – A Gang of Athlons

AMD Socket A Test Board

AMD Socket A Test Board

Processors are tested at many steps in the manufacturing process.  Automated visual inspections are done at several steps during the wafer lithography stage, the individual chips are tested and marked on the wafer before slicing, and then final testing and speed grading during the assembly process.

This board is part of that final test stage,  It is designed to test Socket A (462) CPU’s, 20 at a time.  The board was made by a company called DynaVision in June of 2000, coinciding with the release of AMD’s first Socket A processors.  The board would be used in a test machine, and likely manually loaded with up to 20 processors.  This cannot be a FULL test of the processor as not all signals are brought out (so it may miss a package defect).  All the test, debug and JTAG signals are brought out from each socket, as well as the necessary voltages and CLK signals provided.

A connector by each socket supports, PS_ON, PWERON, ANODE and CATHODE signals, though I am not entirely sure what there are for.  Best guess is thermal management.  Also next to this is 2 signals labeled TEC1 and TEC2, naming that may suggest Peltier junction cooling.

AMD 20 socket test board, circa 2000

AMD 20 socket test board, circa 2000

The board is labeled AMD 317-S6300 and FAB 30-21041B.  Fab 30 could suggest AMD’s Dresden Germany Fab, which would make this board even more interesting, as only a very few processors were assembled/tested at the fabs themselves.  Most production AMD processors were assembled and tested in Penang, Malaysia (since 1972).

Someone at AMD was certainly intimately familiar with the design and use of this board, and its part in AMD’s success in the market.  Now it occupies a few square feet of a wall at the CPU Shack Museum keeping its secrets to itself.

May 3rd, 2015 ~ by admin

AMD AM29501: 8-bits to the ByteSlice

AMD AM29501DC - 10MHz Byte Slice

AMD AM29501DC – 10MHz Byte Slice

AMD is well known for its 2901 bit-slice processor of the 1970’s (being made well into the 1990’s), as well as the previously detailed AM29116 16-bit processor released in 1981. However, the 1980’s brought another AMD design as well, though not as complicated, it is no less interesting.  In 1981, there was not a clear DSP (Digital Signal Processor) architecture, or really purpose built design.  The Signetics 8X300 was well suited for such work, but was not inherently designed for it.  DSP tasks were handled by other processors, or by completely custom designs.  The AM29501 was not designed as a DSP, but it was marketed as a signal processor, at least for the first 5 years of manufacture.  What the 29501 was, was a relatively fast, and pipelined, byte slice processor, basically a highly upgraded AM2901.

As the name suggests, the 29501 processes data 8-bits at a time, and as a slicer, it requires external program control (it lacks a PC (Program Counter) or sequencer).  It has an 8-function ALU, and 6 sets of registers, which can be accessed independently, allowing for a pipelined architecture, multiple instructions may be issued before the first one is completed (as long as they don’t need the same resources).  While the ALU is doing some addition, more data may be fetched, or output to one of the 3 8-bit buses. AMD designed the 29501 to be able to do advanced DSP work, and such work requires multiplication, which is something the ‘501 cannot do itself.  The 29501, however, was explicitly designed to interface to the AM29516/7 16-bit multipliers.   If a multiplication is needed the microprogram controller simply puts it on the multiplier bus and tells the 2951x to handle it.  A fairly advanced system could be built by using a 29116 a 29516 as well as a 29501, building a complete pipelined DSP system.  One of the first designs using the 29501 in such a way was a finger print recognition system, for matching images of fingerprints, a particularly intense DSP task for the 1980’s.

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September 27th, 2012 ~ by admin

EPROM of the Day: AMD AM27C2048 – Shrinking Dies

AMD AM27C2048-150DC – 3 Dies (Click to view larger)

In the semiconductor industry process shrinks are highly sought after.  They result in smaller die sizes for the same part, which results in more chips per wafer, thus increasing revenue.  There are other benefits (typically speed increases and power decreases (aside from leakage)) but from a purely economical stand point, the smaller dies result in more profits.

Rarely do you get to SEE the result of these process changes.  UV-EPROMs fortunately have a window, for erasing them with UV light, that also lets the die be seen.  Here are three AMD AM27C2048 EPROMs.  These are CMOS 2-Mbit EPROM, pretty common in the 1990s.  As you can see that while they are all the same part, the dies are significantly different. While its hard to say for sure without a die analysis, we can make some good estimations based on what foundries AMD had at the time these devices were made.  The first EPROM is date late 1993 which will likely be a 1 micron process.  The second EPROM, dated mid 1997 is a bit smaller, around 20% smaller, which fits with AMD’s 0.8 micron fabs.  The last, and latest, EPROM was made in 1998, likely at the joint AMD-Fujitsu (FASL) plant in Japan.  This would mean it is a 0.5 micron device. The plant was transitioning to 0.35 micron at the time, but that was most likely used for the higher profit Flash memory devices.  By 1998 EPROM’s were on the decline.

Also of note is the different copyrights.  The first two are copyright 1989 while the third is 1997.  Its hard to know for sure (I do not have the microscopes/tools needed to do die analysis) but it is likely the 1 micron to 0.8 micron was an optical shrink. Literally this means that the die (and masks) are scaled down to a new smaller process with no architectural changes.  This is simple and inexpensive.  Sometimes changes will have to be made to support a new process, or make full use of its benefits, so a new layout/masks are made.  This is likely the case with the 1997 copyrighted EPROM.  The design was altered to work with the new, smaller process, and it was significant enough to warrant a new copyright.

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EPROM of the Day

February 17th, 2011 ~ by admin

The AMD 2901 Bit Slicer and Second Sourcing

AMD AM2901ADC – 1977

In August 1975 AMD introduced the ‘100 ns Bipolar microprocessor.’ This was a bit-slice device. Essentially a 4-bit ALU (like a 74181) with functionality (scratch pad memory and accumulator register) to make it work as a processor that could be scaled to any bit width (using the 2909 sequencer and 2910 controller).  Being made in bipolar allowed for the high speed (10MHz at the time was pretty quick).  The introduction of the 2901 also marked the beginning of the end to the competition int he bit-slice arena.  A combination of marketing, second-sourcing, and a good product allowed AMD to completely dominate the bit-slice market.  Even today most bit-slice designs are based on the 2901 from 35 years ago.

At the time there were several other bit-slice processors on the market.  Intel had the 3002 (a 2-bit design), National’s IMP-8 and IMP-16, and the original TTL 74181 were all bit-slice devices.  MMI (which AMD bought in the 1980’s) had introduced the 6701 4bit slice in 1974, a full year before AMD’s 2901.  TI had the SBP0400A and Motorola the MC10800 (in ECL – 1976). So why with all this competition did AMD come to dominate?

Raytheon AM2901ADC – 1980

Second Sourcing

Second sourcing is the licensing of a design to other companies for them to manufacture, market and sell it.  Sometimes its simply a license to manufacture, sometimes it comes with technical assistance, or even complete mask sets to make the device.  There are three main reasons this is done (or was done back in the day)


Guaranteed Availability.

In the 1970’s making IC’s was a relatively new process, one with many bugs, and often reliability issues.  Having a second source was a must to get a big design win. A system design would not want to design a system around a chip that may end up not being available, or not be available in the quantities needed.  Having a second source to get the IC from alleviated this problem.  It gave system designers a stable supply, regardless if the primary source could not keep up, or had a problem.



Second-sourcing helped solve distribution problems as well.  A company may have an excellent design, but no way to sell it.  Often this was a geography problem.  American companies did not initially have a large presence, or distributors set up, in Europe or Japan.  An American company would often second-source a design to a European company (such as Siemens or Thomson) solely to get their design distributed in that area.



One of the keys to a processors success is design wins.  It can be the best processor on the market,. but if no one uses it, it will fail.  Having additional companies make, and market the processor vastly increased its exposure.  Second-source companies would also typically make development systems, and other support tools, as well as vast documentation for the processor.  This helped ensure that engineers knew about the processor, how to use it, and whee to get it, ensuring its winning of more sockets.

Soviet Electronika 1804VS1 – 2901 Clone – 1988

AMD clearly understood the importance of second-sourcing.  In November 1975, just months after the 2901 was released, they designed an agreement with Motorola to make the 2901.  In December, they signed up Raytheon, and in March of 1976 AMD signed an agreement with the SESCOSEM division of Thomson-CSF, to make and distribute the 2901 in markets outside the US and Japan. In June 1976 AMD amended their agreement with Motorola to include more technical assistance, ensuring Motorola could get the 2901 to market. In September 1976 MMI canceled the 6701, as they were unable to compete.  MMI had no second-sources for the 6701 which likely led to its failure.

As the years went by, AMD added more second-sources, and dropped a few. Eventually coming to completely dominate the bit-slice market.  The Soviets began to copy the 2901 around 1985 (not particularly legally but they did what they had to) and continued to do so until well into the 90’s.

Year Second Sources
1975 Motorola
1976 Motorola, Raytheon, Thomson
1977 Motorola, Raytheon, Thomson, National
1978 Motorola, Raytheon, National, Fairchild, NEC, Signetics, Thomson
1980 Motorola, Raytheon, National, Fairchild, NEC, OKI (MSM8821?), Thomson
1982 Motorola (2903), National, Fairchild, NEC, Thomson
1985 National, Thomson, Cypress, USSR
1990 Cypress, IDT, Thomson, National, USSR
1995 Cyrpress, IDT, WSI, Thomson, Russia

Innovasic IA59032 – 8 x 2901 – 2003

AMD also made the AM29C101 which was 4 2901s in a single chip, producing a 16bit processor.  Cypress manufactured a copy of the 29C101 called the CY7C9101

Several other companies also designed multiple 2901s into a single chip. WSI (and later InnovASIC) designed the 59032, which has the equivalent of 8 2901s to form a 32 bit slice and the 59016 which was  16bit slice (4x 2901).  IDT designed the 49C402 which was also a 16 bit slicer.  Today the 2901 is still in wide use, and while not generally used for new designs, it still powers a vast amount of electronic equipment that still is in use.  InnovASIC still manufactures the 2901 (in 59032 form) to this day.

November 18th, 2010 ~ by admin

AMD Bobcat splits the Atom to the Core

AMD recently released the Bobcat line of APUs (Accelerated Processing Units).  These are part of their new ‘Fusion’ line which integrates fairly simple, yet fast, CPU cores with Radeon graphics.  Several sites have benchmarked the Bobcat against the Intel Atom and the results are rather amazing. Engadget has a list of benchmarks as well.

AMD Bobcat Fusion APU - Zacate

The dual core 1.6GHz E-350 dissipates a mere 18W, and containing a Radeon 6310 500MHz 80 core GPU.  In various application tasks it handily beats the Intel Atom, and in video tests (gaming etc) its integrated Radeon GPU does remarkably well.  Its good to remember that the E350 (and others in its family) are designed for netbooks, tablets, etc.  Its good to see AMD taking a bite out of Intel’s Atom.  Its this sort of competition that drives technological advances, and makes processors out of date fast enough for CPU collectors to pick them up.

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Processor News

April 1st, 2010 ~ by admin

AMD Launches ‘Lottery-Core’ CPUs

AMD today unvelied their new CPUs for gamers, which seem to readily appeal to poker players. The New Lottery Core series contains 12 cores. However, as is normal with production of such a complex device some, or all of these cores may not work.  AMD has designed the cores/CPU such that if a core fails, the others will function fine, this of course saves them testing, as well as packaging costs as each chip can use the same package and markings.

Obviously these are targeted specifically for the hobbiest, and priced accordingly. You may get one with all 12 cores functioning and if so AMD considers you ‘very lucky’ apparently not so much if you get one with no working cores.

Currently these are only available in the UK, but if successful should spread elsewhere.

More Info at PC Pro UK


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Processor News