Intel SSQ22667-001 SQ80C186-12 – Space Rated CMOS 80186

Recently some interesting CPUs showed up on eBay and other IC selling sites.  They were marked SSQ22667-001 and made by Intel.  Some were conveniently also labeled SQ80C186-12.  Packaged in a 68-pin CQFP package, they typically would be labeled as a MQ80C186 (Military CMOS 186 running at 12MHz) but these were as ‘SQ’ prefix, and had the weird SSQ22667-001 part # on them as well. Others in the same package were marked SSQ22668 and 22669. So what was special about these CPUs? Was this some random House # for an OEM?  Nope, these were made for NASA, specifically to conform with MIL-STD-975.  To learn a bit more about how these MIL-STD’s work, lets take a journey back to the 1960’s (everyone knows hat was a fun time)

Back in the 1960’s integrated circuits were getting to be more standard, and more available. Many companies were making many different types (generally simple logic at the time, but that was changing fast).  The US Military was, of course, an early user of integrated circuits, as they could afford them, and IC’s allowed for some cutting edge technology.   To make purchasing and stocking such components easier, the military, as they usually do, decided there needed to be some standards, and ICs for the military, should be available in higher standards

Intel MC1702A/B – MIL-STD-883 Class B – 1976

then those destined for your microwave oven or digital alarm clock.  Thus in May of 1968 the MIL-STD-883 was released.  This was (and continues to be, its on Rev L now) a standard created on Test methods and procedures for ICs, any IC’s.  It provides such things as inspection methods, burn-in methods, lot sampling, and a whole host of other ways to test and inspect IC’s.  As the years went by, different Classes of testing were added.  A computer chip the captains coffee pot did not need the same testing as a computer chip destined for a nuclear submarine, or one for use in Space.  Several classes were then created for space, S, V, Q and B, varying in the degree of testing needed.  Obviously a vehicle designed to take people to space should use higher quality parts then one launching unmanned missions.

As IC’s continued to be developed, and many devices became ‘standard’ like various RTL/TTL devices and the like, the Military wanted to define those better for themselves as well.  Thus in 1969 MIL-M-38510 was released.  38510, often called JAN38510 (Joint Army Navy Standard Naming which was used through Rev J in 1991) was a General Specification for Microcircuits.  It provided fit, form and function standards for various devices.  They could be made by anyone, anyway they liked, but to be marked/used as a JAN38510 device they had to meet what it defined that device to do.  This was all

Zilog JAN MIL-M-38510 52002BQA Z8002 CPU – 1987

based on existing devices, it simply took a commercial device, such as a 74181 ALU, and gave it a 38510 description and part number.  This ensured that no matter where the Military got that 38510 standard 74181 ALU it would behave the exact same.  The 38510 standard refer’d back to the MIL-STD-883 testing procedures, it in itself did not define any testing.

As things progressed, MIL-STD-883 with the how, and MIL-M-38510 with the what, NASA decided they should have their own standard (American government agencies like to compete).  Based on the 38510 standard,and the 883 testing standards NASA created MIL-STD-975 in 1976.  This was essentially a list of products that met NASA’s standards for all electronic devices.  Everything from capacitors, diodes, cables, oscillators and even some processors. Ultimately this was a great idea at the time.  It provided designers with a list of parts they could use that NASA had already certified as acceptable, rather then having to test/certify every single piece.  The cost and time saving were immense once the initial certification was done.  The list of certified devices was updated every few years through 1994 when the standard was canceled, likely because there was just too much new devices becoming available to keep up with.  Three levels of quality are used in this standard. Grade 1 parts arc very low risk, higher quality and

Illustration of the Ørsted spacecraft in orbit (image credit: DRSI)

reliability parts intended for critical applications (such as man rated space applications). Grade 2 parts are low risk, high quality and reliability parts for usc in applications not requiring Grade 1 parts. Grade 3 parts are higher risk, good quality and reliability parts but are not recommended for applications requiring high product assurance levels.

These particular SQ80C186s are made by Intel and listed as Grade 3 devices.  This is mainly because Intel decided not to take part in the NASA certification process, so their grading is based on their MIL-STD-883 QML (Qualified Manufacturer List) testing.  These parts were used on many satellite designs (such as PoSAT-1, Portugal’s first satellite in 1993 and the 1999-2014 Danish Ørsted Geomagnetic Mission)  as well as the International Space Station.  Its possible on the ISS they were used in a non-mission critical area where Grade 3 is acceptable.   Even as a Grade 3 device the replacement cost (in 2003) was $2,266.  Today they are a mere collectors item, as parts like these need to have a certified traceability with them, knowing where they have been and how/where they were stored is important to them being certified for use. These particular chips were made in 1993, a lot can happen in 27 years of storage and transport around the world.

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Since we have a complete, and very early mask set of the HP NanoProcessor (donated by Mr Bower, thank you) it seemed fitting to scan them in (tricky at 600 dpi and 6 scans each (they are around 40x60cm) then I sent them over (500MB) my friend Antoine Bercovici in France to stitch and clean, as well as remove the background.  THat allowed this cool animation of the mask being built.
These are made from a set of 100X Mylar masks

Here you can see how the 6 different mask layers are built up.  The last mask layer (black) is the bonding pads
Each individual layer is also shown, some are very simple, while others contain a lot more.

In the lower left corner of the masks you can see their layer number 1B 2A 3A…etc

You can see the original HP part number on the mask 9-4332A as well as ‘GLB’  GLB is a composition of the initials of the two designers of the chip: George Latham and Larry Bower.

Here is a larger version as well: HP NanoProcessor Mask Set

Original Nanoprocessor prototypes from 1974-75. Note hand written wafer number, open die cover and early part number (94332)

Back in the 1970’s the Loveland Instrument Division (LID) of HP in Colorado, USA was the forefront of much of HP’s computing innovation.  HP was a leader, and often THE leader in computerized instrumentation in the early 1970’s.  From things like calculators, to O-scopes to desktop computers like the 9825 and 9845 series.  HP made their own processors for most all of these products.  The early computers were based on the 16-bit Hybrid processor we talked about before.  At around the same time, in 1974, the HP LID realized they needed another processor, a control oriented processor that was programmable, and could be used to control the various hardware systems they were building.  This didn’t need to be a beast like the 16-bit Hybrids, but something simpler, inexpensive, and very fast, it would interface and control things like HPIB cards, printers, and the like.  The task of designing such a processor fell to Larry Bower.

The result was a Control Oriented Processor called the HP nanoprocessor.  Internally it was given the identifier 94332 (or 9-4332), not the most elegant name, but its what was on the original prototypes and die.   The goal was to use HP’s original 7-micron NMOS process (rather then the new 5-micron NMOS-II process) to help save costs and get it into production quickly.

Nanoprocessor Features – Note the speed has been ‘adjusted’

The original design goal was a 5MHz clock rate and instructions that would execute in 2 cycles (400ns).  The early datasheets have this crossed out and replaced with 4MHz and 500ns, yields at 5MHz must not have been high enough, and 4MHz was plenty.

Handwritten Block diagram

The Nanoprocessor is interesting as it is specifically NOT an arithmetic oriented processor, in fact, it doesn’t even support arithmetic.  It has 42 8-bit instructions, centered around control logic.  These are supported by 16 8-bit registers, an 8-bit Accumulator and an 11-bit Program Counter.  Interface to the external world is via an 11-bit address bus, 8-bit Data bus and a 7-bit ‘Direct Control’ bus which functions as an I/O bus.  The nanoprocessor supports both external vectored interrupts and subroutines.  The instructions support the ability to test, set and clear each bit in the accumulator, as well as comparisons, increments/decrements (both binary and BCD), and complements.

Here is one mask (Mask 5 of 6) for the prototype Nanoprocessor. You can see its simplicity.  On the bottom of the mask you can see the 11-bit address buffers and Program Counter

2.66MHz 1820-1691 – note the -5V Bias Voltage marked on it

The Nanoprocessor required a simple TTL clock, and 3 power supplies, a +12 and +5VDC for the logic and a -2VDC to -5VDC back gate bias voltage.  This bias voltage was dependent on manufacturing variables so was not always the same chip to chip (the goal would be -5VDC).  Each chip was tested the and voltage was hand written on the chip.  The voltage was then set by a single resistor on the PCB.  Swapping out a Nanoprocessor meant you needed to make sure this bias voltage was set correctly.

If you needed support for an ALU you could add one externally (likely with a pair of ‘181 series TTL).  Even with an external ALU the Nanoprocessor was very fast.   The projected cost of a Nanoprocessor in 1974 was $15 (or $22 with an ALU),  In late 1975 this was $18 for the 4MHz version  (1820-1692) and $13 for the slower 2.66MHz version (1820-1691).

At the time of its development in 1974-1975 the Motorola 6800 had just been announced. The 6800 was an 8-bit processor as well, made on a NMOS process, and had a maximum clock rate of 1MHz.  The initial cost of the 6800 was $360, dropping to $175, then $69 with the release of the 6502 from MOS.  By 1976 the 6800 was only $36, but this is still double what a Nanoprocessor cost

An early ‘slide deck’ (the paper version equivalent) from December 1974 sets out the What Why and How of the Nanoprocessor.  The total cost of its development was projected to be only $250,000 (around $1 million in 2020 USD).  The paper compares the performance of the Nanoprocessor to that of the 6800.  The comparisons are pretty amazing.

Interrupted Count Benchmark

For control processing interrupt response time is very important, the Nanoprocessor can handle interrupts in a max of 715ns, compare that to 12usec for the 6800.   The clock rate of the Nanoprocessor is 4 times faster but the efficiency of its interrupts and instructions are what really provides the difference here.

The clock rate difference (1MHz vs 4) really shows here, but the Nanoprocessor is also executed 3 times the instructions to do the same task, and still is faster.

Even using an external ALU compared to the Motorola’s internal ALU, the nanoprocessor is better then twice as fast (thanks here to its much higher clock frequency)

Full Handshake Data Transfer. Interfacing to the outside world was the main driver of the Nanoprocessor. Here we see that it can ‘talk’ to other devices much faster then the 6800

All instructions on the Nanoprocessor take 500ns to execute compared to the 1-10u for the 6800.

Today we do benchmarks based on framerates in games, or render times, but you can see that benchmarks were even important back then.  How fast a processor could handle things determined how fast the printer could be, or how fast it could handle external data coming in.  It’s no wonder that the Nanoprocessor continued to be made into the late 1980’s and many of them are still in use today running various HP equipment.

Nanoprocessor User Manual – October 1974

A big thank you to Larry Bower, the project lead and designer of the Nanoprocessor, who donated several prototypes, a complete mask set, and very early documentation on the Nanoprocessor (amongst some other goodies)

Documentation so ealy it has many hand written parts, and some corrections.  This had to be a very annoying oops if it wasn’t caught early on.  Even Engineers get their left and right mixed up on occasion

AMD AM29C327 Engineering Sample -1990

Recently I came across one of the more unusual members of the AMD Am29300 series.  These were a set of processor elements (multipliers, FPUs, ALUS, registers) AMD designed to support AM29000 CPUs as well as for the bases for custom CPU designs.  Some. like the AM29C323 multiplier found common use in video game and other applications.  Others like the AM29C325 32-bit FPU were used in educational experiments and research.  The 29300 (Bipolar) and 29C300 (CMOS) series are not particularly well known due to their obscure and often deeply specialized used.  At the top of the series lies the AMD AM29C327 Double precision (64-bit) FPU.  This FPU has a few tricks up its sleeves and is about as obscure in use as it gets….

The Am29C327 was on of the first chips made on AMDs CS-11A 1.2u processor (an enhancement of the 1.6u CS-11) .  It was first announced in 1987 with sampling to begin in late 1988.  The ‘327 contained over 250,000 transistors and was packed in a 169PGA package.  It is a IEEE754 compliant double precision FPU but also supports IBM and DEC formats.  It has 3 32-bit buses (2 for input and one for output) that, when multiplexed, allow for 64-bit maths.  Its little brother, the ‘325, only supports 32-bit math, and comes in a 145PGA package with around 30,000 transistors (11,000 gates).  So why does going to double precision involve nearly 10 times the transistor count?  It turns out that the ‘327 is more closely related to an actual CPU then a normal FPU.  The ‘325 has all of 8 instructions (add/sub, mult const subtraction and some conversions), while the ‘327 supports 58 instructions.  Of those 58 instructions 35 are Floating point, 1 is system management, and the other 22? Those are a full set of integer instructions.  The ‘327 actually supports more then just floating point.  Its internal ALU is a 64-bit 3 input design, allowing inputs from either the 2 external inputs, the output, a set of 8 64-bit registers, or a set of 6 constants.  Its instructions are 14 bits and it supports pipelining for even faster calculations.  Interestingly, pipelining can be disabled and the FPU will work in straight flow through mode.  So where is such a complicated chip used? Doing complicated math of course.

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PDP-11/05 Front Panel (pic from vintage_electron)

Back in 1972 DEC released the ‘budget’ PDP-11/05 16-bit computer.  The original PDP-11/20 had been released 3 years before and its CPU (the KA11) was based on simple TTL, its ALU could perform adds and that was all, which meant its designers had to get creative in implementing the instruction set.  By 1972 however things had changed, there still was no 16-bit processors available but there was now single chip 4-bit ALU’s.  The ALU was the famous 74181 and formed the heart of the KD11-A, DEC’s 4th processor design (the ‘third’ was the KB11-A which was similar but based on the faster 74S181 and used in the PDP-11/45 and released at the same time) .

The KD11-A consisted of a pair of boards, the M7260 Data Path Module and the M7261 Control Logic and Microprogram Module.  All the processor functional components are contained on these modules. The M7260 Data Path Module contains: data path logic, processor status word logic, auxiliary arithmetic logic unit control, instruction register and decoding logic, and serial communications line interface. The M7261 Control Logic and Microprogram Module contains: internal address detecting logic, stack control logic, Unibus control logic, priority arbitration logic, Unibus drivers and receivers, microbranch logic, microprogram counter, control store logic, power fail logic, line clock, and processor clock.   The M7260 was he brain, and the M7261 told it what to do, containing the microcode to implement the PDP-11 instruction set.  This was the first version (with the 11/45) of the PDP-11 that was microcoded.

Fairchild 934159 74181 MSI 4-bit ALU made on a Bipolar – This example from very early 1971

The KD11-A ran off a single 150ns clock resulting in a raw clock speed of 6.67MHz, however performance was limited by memory access speed. The PDP-11/05 supported up to 32K Words (64KB) of core memory and this memory could only run at a 980ns cycle time.  This limited the 11/05 performance to around 1MHz.  This was still quite good for 1972!.

The 74181 was capable of running at 42MHz (and 90MHz for the 74S181 Schottky TTL versions) but in a set of 4 this drops to about 27MHz (with the carry generator taking some time).   Speed, however, is usually limited by other things rather then the ALU itself.   The 74181 ALU contains the equivalent of 62 logic gates (170 transistors) and can perform 16 different arithmetic and logic functions on a pair of 4-bit inputs.  Ken Shirriff did an excellent die level analysis of a ‘181 thats worth reading.  It includes pretty pictures even.

DEC M7260 – Data Path for the KD11-B CPU – Dated July 1972

This particular KD11-A board is one of the very first made.  It is dated July 20th 1972, a month after the initial release of the 11/05.  The big white chip is a General Instruments AY-5-1012 UART.  To its right you can see thr 4 74181 ALUs.  Each is 4-bit and together they form a complete 16-bit ALU for the CPU. A 74150 Multiplexer helps determine what data goes where.  The 74182 is the Look ahead carry generator for the ‘181’s.  Most of the rest of the chips on the board are ROMs and supporting logic.  There is also 4 Intel C3101A 35ns SRAM chips, these are 16×4 SRAMs used as scratch pad memories and only were used in the very first version of the CPU (later versions replaced them with cheaper 7489 TTL versions).  The Scratch Pad Memory is what forms the registers for the CPU.  There are 16 16-bit registers with the the first 6, R0-R5 being general purpose registers and the rest special purpose such as the Program Counter, Interrupt Vector, etc.

M7261 Control module – Contains the microcode for the CPU (pic from xlat.livejournal.com)

Another interesting point on this board is the very large amount of green wires running on the board.  These are called ECO wires, which are ‘Engineering Change Order’ wires, and are placed, by hand, after the board is made to correct faults in the board layout.  The goal is to not have these as they are expensive and delicate and can result in failures down the road, so further revisions of the board would have these fixed/implemented in the PCB.  You do not see these much at all any more as modern design/testing tools virtually eliminate the possibility of a faulty PCB layout making it into production.

When it was released the ~1MHz 11/05 cost $25,000, which in 2020 US Dollars is around $154,000.  THe PDP-11 series ended up being one of the most popular minicomputers, selling over 600,000 units over the years.  Later versions like the LSI-11 series moved the entire CPU to a single LSI chip, adding Extended Instructions, Floating Point Instructions, faster memories and other performance enhancements well into the 1980’s.   It was also widely comied, and enhanced in the Soviet Union and Russia.  It was on a Soviet PDP-11 clone that Tetris was developed, a game we are all rather familiar with.

Its amazing to see where computers have come in the span of but a few decades. but these important parts of history continue to be used.  Perhaps not the 11/05, but there are many PDP-11 systems still working away, typically inindustrial environments, ironically helping produce things likely far more advanced then themselves.

Fischer & Porter 53MC5 – The beginning of the Mystery

One day last summer, I was browsing the deep dark corners for processors, a fun, yet dangerous activity.  I happened upon a lot of PCBs from some older industrial automation equipment.  No real information was provided (those buying these boards clearly would already know what they needed).  They did however have a RTC, an EPROM a 16MHz crystal, and a large 84-pin PLCC.  That PLCC was marked as an Intel N60066.  Seeing such a large chip, surrounded by such components almost always means its some sort of processor or microcontroller.  The problem is, there is no known Intel 60066 part.  The chips were all made in the late 80’s and early 90’s and had  1980 and 1985 copyrights.  A 1980 copyright typically screams MCS-51, as that was when it was introduced and nearly all such chips bear an Intel 1980 mark.

Intel N60066

The boards themselves were dated from 1990 all the way to the early 2000’s (I bought a lot of them, another problem I have).  Some had the part number 53MC5 and the logo of Fischer & Porter.  Fischer & Porter has existed since the 1930’s and was a leader in instrumentation.  They were bought by Elsag Bailey Process Automation (EBPA) in 1994 which itself was swallowed up by ABB in 1999.  The boards design was largely unchanged through all of these transitions. Searching for documentation on the 53MC5 part number (its a Loop Controller) didn’t yield details on what the N60066 was unfortunately.  The only thing left to do was to set it on fire…

Unfortunately this is the only way I currently have for opening plastic IC’s (I need to get some DMSO to try apparently).  After some careful work with the torch and some rough cleaning of the resulting die it was readily apparent that this was an MCU of some sort.  The die itself was marked… 1989 60066.  This wasn’t a custom marked standard product, this was a custom product by Intel for this application, a very surprising thing indeed.  Unlike other companies such as Motorola, Intel was not well known for custom designs/ASICs.  This wasn’t their market or business plan.  Intel made products to suit the needs they saw, if that worked for the end user, great, if not, perhaps you could look elsewhere.  They would gladly modify specs/testing of EXISTING parts, such as wider voltage ranges, or different timings, but a complete custom product? Nope, go talk to an ASIC design house.  Its likely Fischer & Porter ordered enough of these to make it worth Intel’s effort.

Knowing this was an MCU and suspecting a MCS-51 further searching revealed the answer, and it came from the most unusual of places.  In 2009 the US NRC (Nuclear Regulatory Commission) determined there was no adequate Probabilistic Risk Assessment (PRA) for Digital systems in their agency, so set about determining how best to calculate risk of digitally controlled systems.  They analyzed a system used to control feedwater in nuclear reactors.  These are critical systems responsible for making sure the reactor is kept with the right amount of cooling water at the right time, failure of course is not an option.  The 53MC5 is what is used for controlling the valves.  In this document we find this nugget:

The controller is an 8051 processor on board an application-specific integrated circuit (ASIC) chip that performs a variety of functions.

Well that certainly helps, it is indeed a custom ASIC based on an 8051.  The report also provided a diagram showing the ASIC system.  This is an 8051 core with RAM/ROM (normal) as well as a Watchdog timer, a PAL, I/O Buffers, and Address Logic.

I sent a couple of these chips to my friend Antoine in France for a proper die shot, which he is quite amazing at.

Intel N60066 die – 8051 core on the left. Die shot by Antoine Bercovici

The 8051 core is on the left of the die, with its RAM/ROM.  A very large PLA occupies the bottom right side of the day.  In the upper right is presumably the external watchdog timer for the ASIC.  The lines crossing the die mostly vertically are a top metal layer used for connecting all the various sections.

The hunt for a new CPU/MCU is part of the thrill of collecting.  The satisfaction of finding out what a mystery chip is can be worth many hours of dead ends in researching it.  Its not common to have to go to the NRC to find the answer though.

Racks of external modems at an ISP back in the day

Back in the 1990’s I worked at several ISP’s in my hometown.  These were the days of dial up, and by working at the ISP I got free dial up access which my family and I enjoyed.  We had several racks (white wire racks) of external modems for dial in.  This was the most common solution for smaller ISPs.  External modems were usually more reliable, cheap and easy to replace if/when they failed (and they did).  They got warm so it wasn’t uncommon to see a fan running to help move more air.  Surprisingly I could only find a few pictures of a such installations but you get that idea.

By the late 1990’s as dial in access and ISPs grew to be major concerns dial up solutions became much more sophisticated.  Gone were wire racks of modems and in were rackmount all in one dial in solutions.  These included boards that hosted dozens of modems on one PCB. with their own processing and management built in.  One of the largest companies for these solutions was Ascend Communications.  Their ‘MAX TNT’ modem solution once boasted over 2 million dial up ports during the 1990’s.  Such was Ascends popularity that they merged with Lucent in 1999, a deal that was the biggest ever at its time, valued at over $24 Billion ($37 Billion in 2020 USD). It wasn’t just traditional ISPs that needed dial up access, ATM’s and Credit Card processing became huge users as well.  It wasn’t uncommon to try to run a credit card at a store in the 1990’s and have to wait, because the machine got a busy signal.  The pictured Ascend board has 48 modems on a single PCB, and would be in a rack or case with several more boards, supporting 100s of simultaneous connections.

Ascen CSM/3 – 16x Conexant RL56CSMV/3 Chips provide 48 modems on one board.

Ascend’s technology was based primarily on modem chips provided by Conexant (Rockwell Semiconductor before 1999).  Rockwell had a long history of making modem controllers, dating back to the 1970’s.  Most of their modem controllers up through the 80’s and early 90’s were based on a derivative of the 6502  processor.  This 8-bit CPU was more the adequate for personal use modems up to 33.6kbaud or so, but began to become inadequate for some of the higher end modems of the 1990’s.  These ran at 56k, supported various voice. fax, and data modes and handled a lot of their own DSP needs as well.  Rockwell’s solution was to move to an ARM based solution, and integrate everything on chip.

One of the results of this was the Anyport Multiservice Access Processor. It was called the Multiservice Access Process because it handled, voice, data, 33.6/56k, ISDN, cellular, FAX and several other types of data access, and it did so in triplicate.  The RL56CSMV/3 supported 3 different ports on one chip.  The CSM3 series was the very first ARM cored device Rockwell produced.  Rockwell had licensed the ARM810 (not very common), the ARM7TDMI and a ‘future ARM architecture’ (which was the ARM9) back in January of 1997.  In less then two

Conexant RL56CSM/3 R7177-24 ARM7 (non-V version has no voice support)

years Rockwell had designed and released the first AnyPort device, remarkable at the time.  The CSM/CSMV used the ARM7TDMI running at 40MHz and made on a 0.35u process.  The CSM/CSMV has another interesting feature, and thats the backside of the chip….

Take a look of the backside of the 35mm BGA chip, the ball arrangement is very unusual!  There is a ring of balls around the outer edge and 4 squares of 16 balls inside of that.  This is a multi-die BGA package.  There are 4 die inside one BGA package, three dies for the 3 Digital Data Pumps (DDPs) and a seperate die for the ARM7 MCU (which is made on a different process then the mixed signal DDPs).  Most of the balls in the 16×16 squares are to be connected to GND, and used for thermal dissipation (dissipating heat via the main PCBs ground plane).  Its not uncommon to see multidie packages today, but a multi die BGA package in 1999 was fairly innovative.

Surprisingly many of these chips are still in service, in today’s world of high speed broadband connections there are still many who are stuck on dial up.  As recently as 2015 AOL was still serving 2.1 million dial up customs in the US (out of around 10 million dial up customers total), which was still netting the company nearly half a billion dollars a year (by far their largest source of revenue at the time.  There is also still plenty of other infrastructure that still rely on dial up, ISDN, and even FAX services that require end point connections like the CSMV so its end is probably still a long ways off.

Milstar Satellite

Back in the late 1970’s having a survivable space based strategic communications network became a priority for the US Military.  Several ideas were proposed, with many lofty goals for capabilities that at the time were not technologically feasible.  By 1983 the program had been narrowed to a highly survivable network of 10 satellites that could provide LDR (Low Data Rate) strategic communications in a wartime environment.  The program became known as MILSTAR (Military, Strategic, Tactical and Relay) and in 1983 President Reagan declared it a National Priority, meaning it would enjoy a fair amount of freedom in funding, lots and lots of funding.  RCA Astro Electronics was the prime contractor for the Milstar program, but during the development process was sold to GE Aerospace, then Martin Marietta, which became Lockheed Martin before the 3rd satellite was launched.  The first satellite was suppose to be ready for launch in 1987, but changing requirements delayed that by 7 years.

Milstar Program 5400 series TTL dies

The first satellite was delivered in 1993 and launched in February of 1994.  A second was launched in 1995 and these became Milstar-1. A third launch failed, which would have carried a hybrid satellite that added a Medium Data Rate (MDR system).  Three Block II satellites were launched in 2001-2003 which included the MDR system, bringing the constellation up to 5.  This provided 24/7 coverage between the 65 degree N/S latitudes, leaving the poles uncovered.

TI 54ALS161A

The LDR payload was subcontracted to TRW (which became Northrup Grumman) and consisted of 192 channels capable of data rates of a blazing 75 – 2400 baud.  These were designed for sending tasking orders to various strategic Air Force assets, nothing high bandwidth, even so many such orders could take several minutes to send.  Each satellite also had two 60GHz cross links, used to communicate with the other Milstar sats in the constellation.  The LDR (and later MDR) payloads were frequency hopping spread spectrum radio system with jam resistant technology.  The later MDR system was able to detect and effectively null jamming attempts.

The LDR system was built out of 630 LSI circuits, most of which were contained in hybrid multi layer MCM packages.  These LSIs were a mix of custom designs by TRW and off the shelf TTL parts.  Most of the TTL parts were sourced from TI and were ALS family devices (Advanced Low Power Schottky), the fastest/lowest power available.  TI began supplying such TTL (as bare dies for integration into MCMs) in the mid-1980’s.  These dies had to be of the highest quality, and traceable to the exact slice of the

Traceability Markings

exact wafer they came from. They were supplied in trays, marked with the date, diffusion run (a serial number for the process and wafer that made them) and the slice of that wafer, then stamped with the name/ID of the TI quality control person who verified them.

These TTL circuits are relatively simple the ones pictures are:
54ALS574A Octal D Edge Triggered Flip flop (used as a buffer usually)
54ALS193 Synchronous 4-Bit Up/Down Binary Counters With Dual Clock
54ALS161A Asynchronous 4-Bit Binary Counters

ALS160-161

Looking at the dies of these small TTL circuits is quite interesting.  The 54ALS161A marking on the die appears to be on top of the a ‘160A marking.  TI didn’t make a mistake here, its just that the the 160 and 161 are essentially the same device.  The 161 is a binary counter, while the 160 was configured as a decade counter.  This only required one mask layer change to make it either one.

ALS573 and ALS574 die

Similarly with the 54ALS574, which shares a die with the more basic ‘573 D type transparent Latch.  This was pretty common with TTL (if you look at a list of the different 7400 series TTL you will notice many are very similar with but a minor change between two chips).  It is of course the same with CPUs, with one die being able to be used for multiple core counts, PCI0E lanes, cache sizes etc.

Together with others they perform all the function of a high reliability communications systems, so failure was not an option.  TI supplied thousands upon thousands of dies for characterization and testing.  The satellites were designed for a 10 year lifetime (it was hoped by them

Milstar Hybrid MCM Command Decoder (picture courtesy of The Smithsonian)

something better would be ready, no doubt creating another nice contract, but alas, as many things are, a follow on didn’t come along until just recently (the AEHF satellites).  This left the Milstar constellation to perform a critical role well past its design life, which it did and continues to do.  Even the original Milstar 1 satellite, launched in 1994 with 54ALS series TTL from the 1980s is still working, 25 years later, a testament to TRW and RCA Astro’s design.  Perhaps the only thing that will limit them will be the available fuel for their on-orbit Attitude Control Systems.

While not necessarily a CPU in itself these little dies worked together to get the job down.  I never could find any of the actual design, but it wouldn’t surprise me if the satellites ran AMD 2901 based systems, common at the time or a custom design based on ‘181 series 4-bit ALUs.  finding bare dies is always interesting, to be able to see into whats inside a computer chip, but to find ones that were made for a very specific purpose is even more interesting.  The Milstar Program cost around $22 Billion over its life time, so one must wonder how much each of these dies cost TRW, or the US Taxpayer?

Motorola MC68040VL

A month or so ago a friend was opening up a bunch of unmarked packages, and taking die photos and came across an interesting Motorola.  The die looked familiar, but at the same time different.  The die was marked 68040VL, and appeared to be smaller version of the 68040V.  The Motorola 68040V is a 3.3V static design of the Motorola MC68LC040 (It has dual MMUs but lacks the FPU of the 68040).  The 68040V was made on a 0.5u process and introduced in 1995.  Looking closely at the mask revealed the answer, in the form of 4 characters. F94E

Motorola Mask F94E – COLDFIRE 5102

Motorola uses mask codes for nearly all of their products, in many ways these are similar to Intel’s sspecs, but they are more closely related to actual silicon mask changes in the device.  Multiple devices may use the same mask/mask code just with different features enabled/disabled.  The Mask code F94E is that of the first generation Motorola COLDFIRE CPU, the MCF5102.  The COLDFIRE was the replacement for the Motorola 68k line, it was designed to be a 32-bit VL-RISC processor, thus the name 68040VL for VL-RISC. .  VL-RISC architectures support fixed length instruction (like a typical RISC) but also support variable length instructions like a traditional CISC processor.  This allows a lot more code flexibility and higher code density.  While this may be heresy to RISC purists it has become rather common.  The ST Transputer based ST20 core is a VL-RISC design, as is the more modern RISC-V architecture.  The COLDFIRE 5102 also had another trick, or treat up its sleeve.  It could execute 68040 code.

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Winbond W77E58P-40 – Your typical Winbond MCS-51 MCU

Winbond Electronics was founded in Taiwan back in 1987, and is most widely known for their memory products and system I/O controllers (found on many motherboards of the 1990s).  They also made a wide variety of microcontrollers, mostly based on the Intel MCS-51 core, like many many other companies have and continue to do.  They also made a few 8042 based controllers, typically used as keyboard controllers, and often integrated into their Super I/O chips.  So why do I find myself writing about Winbond, whose product portfolio seems admittedly boring?

It turns out, that once upon a time, Winbond decided to take a journey on a rather ambition path.  Back in the early 1990’s they began work on a 32-bit RISC processor, and not an ARM or MIPS processor that were just starting to become known at the time, but a processor based on the HP PA-RISC architecture. This may seem a odd, but HP, in a shift form their previous architectures, wanted the PA-RISC design to be available to others.  The Precision RISC Organization was formed to market and develop designs using the architecture outside of HP.  HP wanted to move all of their non-x86 systems to a single RISC architecture, and to help it become popular, and well supported, it was to be licensed to others.  This is one of the same reasons that made x86 so dominate in the PC universe.  More platforms running PA-RISC, even of they were not HP, meant more developers writing PA-RISC code, and that mean more software, more support, and a wider user base.  Along with Winbond, Hitachi and OKI also developed PA-RISC controllers.  Winbond’s path was innovative and much different then others, they saw the need for easy development as crucial to their products success, so when they designed their first PA-RISC processor, the W89K, they made it a bit special.

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