May 13th, 2020 ~ by admin

Chapter 2: Mini-Mainframe at Home: The Story of a 6-CPU Server from 1997

At the end of 2018, I started one project, which was called “Mini-Mainframe at Home: The Story of a 6-CPU Server from 1997”. It was dedicated to the ALR Revolution 6×6 super server with six Intel Pentium Pro processors and a cost comparable to that of a brand new Ferrari in 1997. It took some 450 days and finally follows the continuation of the story, the super server received the long-awaited upgrade – six Intel Pentium II Overdrive 333 MHz Processors! For those years, such power was simply colossal, but how it compares with today’s and how much increased performance you will learn from this article.

I’ll admit 450 days is quite a long time, so I will briefly recall the contents of the previous series of the article.
And it all started like this: plunging into the world of mainframes and supercomputers , I wanted to try some super powerful system and the choice fell on the ALR Revolution 6×6 super server, which had six Socket 8 and supported up to 4 GB of RAM. For the late 90s, these were scary numbers, as well as its cost. One processor for such a system was estimated by Intel at $ 2675, and six were required, for one module of 256 MB of server memory it was necessary to pay $ 3500, and sixteen sticks were needed to get the coveted 4 GB of RAM.

A disk subsystem was also available with seven raid controllers and an 860 GB disk array, a twenty-kilogram power supply unit and the server itself … As a result, it was possible to reach amounts from 270 to 500 thousand dollars, and if you add here the inflation level over the years, these numbers will range from 435 to almost 800 thousand dollars. Now, in terms of performance, any low-cost computer will be faster than this monster, but the very fact of having such an opportunity in 2020, to feel the full power of that time, makes these large numbers insignificant, it is much more important to find and assemble such a monster.

ALR 6×6 Available Options

In the previous story, I studied performance with six Intel Pentium Pro processors with a frequency of 200 MHz and a 256 KB second-level cache and even overclocked all six copies to 240 MHz. As well as six top-end Intel Pentium Pro “black color” with a frequency of 200 MHz and a 1M L2 cache, which were able to overclock to 233 MHz. In my configuration, I had 2 GB of RAM standard FPM, 16 memory modules of 128 MB, which took over 4 minutes to initialize during the initial POST procedure.

Four gigabytes of RAM would bring this figure to 9 minutes, which is comparable to accelerating a train or taking off an airplane, although the latter can do it much faster. But then, having loaded at my disposal, six physical cores arrived at once, but without the support of MMX and especially SSE instructions.

Intel Pentium II Overdrive 333 MHz processor

The basis of any computer is the central processor. Intel Pentium Pro processors first appeared in 1995. Then there were the usual Pentiums without the Pro prefix, but this prefix in the name of the models said that these processors are positioned primarily as solutions for servers and workstations with their special Socket 8. The usual Intel Pentiums were installed in Socket 5 and 7. A significant difference between the Pro and the regular version of the Pentium desktop was the presence of a second-level cache in the Pro version, which, being on the same package, worked at the processor’s core frequency, thus allowing it to significantly increase performance.

For the various Intel Pentium Pro models, the L2 cache size ranged from 256 KB to 1 MB. Pentium Pro’s first level cache was 16 KB, of which 8 KB was for data and the same for instructions. For the subsequent Intel Pentium-IIs, the second-level cache worked at half the processor core frequency and amounted to 512 KB for all models, and it was located in the form of separate microcircuits on the cartridge at a distance from the CPU die itself. The L1 cache size was doubled in size to 32K, which offset the performance hit of the slower L2 cache.

Pentium Pro Slot 1 Slockets – Also made were Slot 2 versions.

The tested processors were produced at a 350 nm process technology. The number of transistors in the Pentium Pro totaled 5.5 million for the processor core itself and as many as 15.5 – 31 million were in the L2 cache memory, depending on its size. The L2 cache itself was located on a separate die near the CPU core. The processor had a free multiplier and the system bus frequency, depending on the model, was 60 or 66 MHz. Overclocking of the processor rested on overclocking the L2 cache, it the limiting factor.

CPU core on the right, L2 cache on the left

The Intel Pentium II Overdrive 333 MHz was a very interesting processor. This processor appeared, it can be said, thanks to the US Government, which funded a program to create supercomputers for modeling nuclear explosions and tracking the state of the country’s nuclear arsenal. The US government allocated funds for the construction of such a supercomputer, Intel won the tender and in 1997 handed over a turnkey supercomputer called “ASCI Red”.

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April 16th, 2020 ~ by admin

DEC M7260 KD11-A CPU: The PDP-11 Goes MSI

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.

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March 20th, 2020 ~ by admin

The Intel N60066: Unwrapping a Mystery

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.

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February 9th, 2020 ~ by admin

ESA Solar Orbiter: When SPARCs Fly

ESA ERC-32SC

ERC-32SC – SPARC V7 MCM with RAM and MIL-STD-1553

In a few hours (assuming no more delays, UPDATE: Launch Successful) the joint NASA/ESA Solar Orbiter mission will launch on a ULA Atlas 5 Rocket out of Florida, USA.  This is a mission a long time coming for the ESA, which like NASA has to get its funding from the government, except in the case of ESA, that involves the governments of many countries in the EU, which can make planning a bit more tricky.  The mission was originally baselined in 2011 and hoped to launch in…2013…then 2017..then 2018 and finally a launch date in 2020.  The original proposal dates to the late 1990’s as a mission to replace the joint NASA/ESA SOHO Solar mission that had launched in 1995.  This creates some interesting design choices for a mission, as designing often happens before a mission is completely approved/funded.  For Solar Orbiter this is one of the main reasons for it being powered by a computer that by today’s standards is rather dated, space standards no less!

Solar Orbiter – ESA

The Solar Orbiter is powered by a processor designed by the ESA, the ERC-32SC.  This is the first generation of processors designed by the ESA.  It is a SPARC V7 compliant processor running at 25MHz and capable of 20MIPS.  The ERC-32SC is a single chip version of the original ERC-32 which was a MCM (Multi chip Module) containing 3 dies that made up the processor (the Atmel/Temic TSC691 Integer Unit TSC692 FPU and TSC693 Memory Controller) that was made on a 0.8u CMOS process.  The Single chip version was made possible by a processes shrink to 0.5u.  It was also made by Atmel,  (whom acquired Temic) and is commercially known as the TSC695 as it is designed for space use, is capable of handling a 300krad Total Ionizing Dose of radiation.  The computer used in the Solar Orbiter was built by RUAG and has two seperate ERC-32SC processor systems for redundancy.  Each of the ERC-32SCs are actually mounted on a MCM, the single chip SPARC, 48MB of DRAM (38 of which is used, the remainder is for Error Detection/Correction via Reed Solomon method), and a MIL-STD-1553 bus controller/RTC/IO are included in the package.

Fujitsu MB86900 – Original SPARC V7 Processor from 1987

The original specifications for this processor were developed back in the 1990’s, which is why it is a SPARC V7, equivalent to the very first Sun SPARC workstations of the late 1980’s powered by the likes of the Fujitsu MB86900/MB86901.  The ESA has developed several follow on processors since, all based on the later SPARC V8 architecture.  They are faster, and more efficient then the ERC-32SC, with some even being dual core processors.  They are known as the LEON-2 and the later LEON-3.  LEON2 has a 5-stage pipeline and no SMP support, while LEON3 increases the pipeline to 7-stages and adds SMP support.  LEON3 is also a VHDL core able to be added to many ASICS/FPGAs (LEON2 is a hard core).  The Solar Orbiter also has both LEON2 and LEON3 processors on board as well…

The Solar Orbiter caries with is 10 different scientific instruments, and each of them has their own processing subsystem, 9 of which are powered by LEON SPARC processors.  Its common for the main processor of a spacecraft to be the most powerful, but in this case the instruments each possess their own processor more powerful then that of the main spacecraft computer.   This is in large part due to many of these instruments being designed well after the original spacecraft bus and systems were baselined.  Payloads can be added/changed much later in the design of the spacecraft allowing their designers to use more modern computers.

Instrument Processor(s) Notes
Solar Orbiter OBC ERC-32SC – Atmel TSC695 Spacecraft Platform Processor
SoloHi LEON3FT – Microsemi RTAX2000 FPGA
MAG-IBS/OBS LEON3FT – Microsemi RTAX2000 FPGA
RPW-SCM/ANT LEON3FT – Microsemi RTAX4000D FPGA
LEON3FT – Cobham UT699
Two processors
SWA-HIS/EAS/PAS LEON2FT – Atmel AT697F up to 100MHz
EPD-SIS LEON2FT – IP Core
STIX LEON3FT – Microsemi RTAX2000 FPGA
EUI LEON3FT – Cobham UT699 66MHz Single core
METIS LEON2FT – Atmel AT697F
PHI LEON3FT – Cobham GR712RC Dual core up to 100MHz
SPICE 8051 + FPGA Long live the MCS-51

There is also likely more processors on this mission as well, but it can be hard to track them all down, nearly every system has its own processing (star trackers, radios/ attitude control etc)

So as you watch the launch tonight, and perhaps see science/pictures from the Solar Orbiter (or just benefit from its added help in predicting solar storms and allowing us here on Earth to prepare for them better) think of all the SPARCs it has taken to make it function.

 

January 24th, 2020 ~ by admin

ARMing the Modems of the 1990’s

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.

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January 14th, 2020 ~ by admin

Barn Find MOS MCS6502 – A Restoration

ATARI Arcade BoardIn car collecting one of the ‘holy grail’ experiences is the ‘Barn Find’  finding and recovering a rare vehicle that has sat untouched, in some barn, or shed for some time.  They are often in rough, but original condition and can evoke much excitement.  As it turns out CPUs are not so different.  I recently purchased a very rough and very old ATARI Arcade board.

The pictures clearly showed it in terrible condition, with lots of oxidation and ‘stuff’ on it.  But it also had a white MOS 6502 processor.  These are some of the very first CPUs made by MOS and are rather desirable, as in addition to their use by ATARI, they were used in the very first Apple computer, the Apple 1.

When the board arrived it was clearly in bad shape, take a look at that nastiness.  What you can’t see, or rather smell, is the cow manure.  Clearly this board was in an actual barn at some point.  Probably relegated to such a retirement after serving in an Arcade parlor or bar for some time, either that or there was some bovin gaming going on.

You can see there is some oxidation on the lids of the various chips as well.  The ROMs and CPU are in sockets.  These sockets are nice, they are not a machine socket but rather a LIF, Low Insertion Force Socket, that helps as the pins on these chips are very delicate, and very possibly corroded.

Before attempting to remove the MCS6502 its best to see what I am working with, so I pulled some of the ROMs nearest to the 6502 to see how their pins looks and how easy they came out of their sockets.  They came out with not a lot of effort but you can see there is some oxidation on the pins.  What we do not want is the pins to be rusted TO the socket and then break off from the forces needed to remove the chip from the socket.

To help mitigate this risk I used some penetrating oil on the pins in the socket.  It seems strange to be squirting oil in the socket but it works.  It will help penetrate the rust and decrease the force needed to remove the 6502. After adding the oil I let the board sit on my heater in my office for several hours.  This helps the oil penetrate, as well as made my office smell like Deep Creep and cow manure, all in a days work.

Then I very gently work on removing the 6502, testing how tight it is and working it out from both ends.  It comes looses with very little drama, hopefully with all its pins intact….

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January 2nd, 2020 ~ by admin

Chips in Space: Making MILSTAR

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?

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December 27th, 2019 ~ by admin

RIP Chuck Peddle: Father of the 6502

Original MOS 6501 Processor from 1975 – Designed by Chuck Peddle.

On December 15th one of the truly greats of processor design passed away at age 82.  Chuck Peddle, born in 1937, before semiconductors were even invented, designed the 6502 processor back in 1974.  The 6502 (originally the 6501 actually) went on to become one of the most popular and widely used processors of all time.  It powered the likes of the Apple 1, Commodores, ATARIs and hundred of others.  It was copied, cloned, and expanded by dozens of companies in dozens of countries.  It was so popular that computers were designed to use it in the Soviet Union, eventually making their own version (Pravetz in Bulgaria).

Sitronix ST2064B – Based on the 65C02 – Core is visible in the upper right of the die. (photo by aberco)

The 6502 was a simple but useful 8-bit design, which meant that as time went along and processors migrated to 16 32 and 64-bits and speeds jumped from MHz to GHz the venerable 6502 continued to find uses, and be made, and expanded.  Chuck continued to be involved in all things 6502 until only a few years ago, designing new ways to interface FLASH memory (which hadn’t been invented when he designed the 6502) to the 6502.

The chips themselves, now in CMOS of course, continue to be made to this day by Western Design Center (WDC) and the 65C02 core is used in many many applications, notably LCD monitor controllers and keyboard controllers.  We can hope that the 6502 will have as long of life as Mr. Peddle, though I woud wager, that somewhere, somehow , in 2056 a 6502 will still be running.

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November 1st, 2019 ~ by admin

CPU of the Day: Motorola MC68040VL

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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October 7th, 2019 ~ by admin

The Forgotten Ones: RISCy Business of Winbond

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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