July 10th, 2014 ~ by admin

CPU of the Day: NEC 78C11 Sample and the 78K family

NEC uPD78C11 ES for Mask ROM

NEC uPD78C11 ES for Mask ROM

Most microcontrollers store the program they run in ROM, most of the time this ROM takes the form of a Mask ROM.  This means that its set at the factory when the die is being made, one layer (or more) of the die contains the ROM and the program is hardcoded into the device.  Development versions almost always exist that allow programs to be developed before the mass produced Mask ROM chip, but still the mask must be tested.

This is such an example from NEC.  It is a engineering sample of a uPD78C11 made in 1988.  the 78C11 (and many others in the 78k family) used a 64 pin QUIP (Quad Inline Package),  The 2 rows of staggered pins allowed for a 64 pin DIP in a much smaller foot print.  The only problem was these chips are extremely delicate.  They were designed to be soldered in and never removed.  The standard package was plastic, but for the sake of testing, these are ceramic (its a bid easier to place/bond the dies on small batches on a ceramic package)

The NEC 78k family was and continues to be very popular.  Its current version (the RL78) is made by Renesas, which was formed when Mitsubishi, Hitachi, and NEC joined their semiconductor businesses.  78K processors powered everything from word processors to washing machines and sewing machines.  Now they are also commonly found in automotive applications.

NEC uPD7811G - 1988

NEC uPD7811G – 1988

Like many modern microcontroller families the NEC 78k traces its lineage back to the 1970′s.  The family first appeared in 1980 as the uPD7801.  The 7801 was a microcomputer based on the NEC 780 which was NEC’s version of the Zilog Z80.  The 781x series released in 1982 expanded on the architecture by including an ADC, as well as a full 16-bit ALU (versus the 8-bit from the 780 and 780x) that even supported 16-bit multiply and divide.  The 16-bit ALU made it a simple task for NEC to again extend the architecture to a 16-bit version.  The instruction set was similar, though the naming was different then the Z80.  In 1985 NEC moved the 78k line to a CMOS process, reducing power requirements and increasing the max clock from 12 to 15MHz.

The inclusion of many peripherals made the 78k a popular choice for many embedded applications.  Its continued availability, and wide code base have allowed it to continue to thrive.  And once again, a ‘modern’ MCU is based on a design from the 1970′s.  Processor architectures rarely die, they just continue morphing.

January 17th, 2014 ~ by admin

Zilog Packaging Marketing Kit

Zilog Packages available in 1985

Zilog Packages available in 1985

Last week we showed you an educational kit from Zilog showing the process involved in making and assembling a Z80 processor, from polished wafer to packaging.  Zilog also made a kit for marketing the various packages used.  This kit contains a shrink DIP 64 pin socket, a shrink DIP 64pin package, a 48 pin DIP and 40 pin DIP, all the common packages used at the time.

Zilog Packages - Z8 Z80 Z800 and Z8000

Zilog Packages – Z8 Z80 Z800 and Z8000

At the time is a little hard to track down as no date is provided with this kit.  We can get very close though looking at the back where Zilog lists which devices are available in these packages.  The usual Z80 and Z8000 series are both there as well as the Z8 microcontroller family.  The one odd-ball is the Zilog Z800.  The Z800 was an upgraded Z80 released in 1985, adding on chip cache an MMU and a vastly expanded instruction set (over 2000 instruction/addressing modes).  It was wholly unsuccessful partly do to bad marketing by Zilog, and partly because it did more then it needed to. It never entered mass production, and by 1986 Zilog has redesigned it, converted the design to CMOS (from NMOS) and released it as the Z280 which met the same fate as the Z800.  It seemed that making an overly complicated Z80 wasn’t what the market wanted.  THe Z180 (designed by Hitachi) and the Zilog eZ80 (released in 2001), have enjoyed much wider success, mainly because they kept closer to the simplicity of the original Z80.

So when was this kit put together? Likely 1985, as the Z800 was nly talked about for a few months before quietly being put away.

April 1st, 2011 ~ by admin

Osborne Computer: The Rise and Fall

Technologizer has published a very interesting article on Osborne Computers, and its founder, Adam Osborne.  Osborne computers was started 30 years ago (April 3rd 1981).  They were the fastest growing, and fastest failing company in Silicon Valley, impressive even today. Adam Osborne was one of the most important people in Silicon Valley (along with Bill Gates and Steve Jobs).  His books in the 70′s are still invaluable resources for collectors, I have several editions of ‘An Introduction to Microcomputers’ which provide an invaluable reference to some of the chip designs of the 1970′s and early 1980′s.

The Osborne 1, the first wildly successful portable, was based on a Zilog Z80A processor and ran the then popular CP/M OS.  If it wasn’t for cash flow problems, Osborne computers may very well have still been making computers today.  It is also interesting that Mr. Osborne had a habit of picking designs that ended up to be not very successful (he chose the Zilog Z8000 and Intel 8089 I/O processor as ‘Chips of the Year’ in 1980)

October 15th, 2010 ~ by admin

Zilog: The First Decade: Z80, Z8 and the Z8000

In 1974 Federico Faggin left Intel after working on the 8-bit 8080 processor.  He formed a company called ZiLOG and developed a much improved version of the 8080 called the Z80.  It was released in 1976 after only 18 months of design.  The Z80 was faster, cheaper, and simpler to build around then the 8080 and enjoyed extremely wide use.  ZiLOG designed the CPU but it was marketed differently then most at the time.  Any company could purchase a license to the design, and build them royalty free.  They were also free to do with the design as they pleased.  This resulted in dozens of companies making clones/versions of it. The Soviets made unlicensed copies as well. In fact other companies made more Z80s then ZiLOG did themselves.

Zilog Z-80 CPU 8400X CS - 1979 2.5MHz

The Z80 was not the only processor that ZiLOG made.  Some of the processors/part numbering can be a bit confusing so we’ll look at each family and part that Zilog made up through 1985.  After 1985 CMOS designs came out as well as dozens of variations.  We just want to look at the first ten years of ZiLOG.

Zilog Z8300-3PS - 1984 2.5MHz

The Z80 itself was, of course, similar to the 8080 but single voltage, and only required a single clock phase.  It was available in speeds of 2.5-8MHz.  ZiLOG also made a low-power version known as the Z80L (Z8300) that ran from 1-2.5MHz.  That’s really all there was to the Z80 family up through 1985.

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February 20th, 2009 ~ by admin

Zilog strips down to its core

In a recent deal to try to solve their cash problems, and streamline profitability, Zilog sold off its secure transaction products (namely 32bit ARM processors) to Maxim (who through the purchase of Dallas, makes many MCS-51 controllers),  They also sold off their wireless division to Maxim (and the software portion of this to a company called UEI)

What does this leave? Essentially the classic Z80 processor that has been around for the last 33 years, and all the related extentions there of.  Old designs tend to stick around for a long time, and the Z80 is no exception.

Source: EE Times