May 14th, 2017 ~ by admin

SESCOSEM and the French 6800

SESCOSEM SFF96800K – Dated 7651 and made by Motorola

Sescosem was a French company that was formed during the merger of Thomson-Brandt and CSF in 1968.  Thomson-Brandt has its roots as a French subsidiary of GE back in 1892 as Compagnie Française Thomson-Houston (CFTH), while CSF was a French electronics company founded in 1918.  Thomson’s SESCO division (itself a joint venture between Thomson and General Electric) was merged with CSF’s COSEM division to form SESCOSEM.  SESCOSEM made many semiconductor products for the European market, starting with basic transistors and eventually second-sourcing microprocessors.

Sescosem SFF71708K – Mid 1978 – 2708 EPROM – Note the SESCOSEM logo

SESCOSEM began to work as a second-source for Motorola in September 1976.  Somewhat unusually SESCOSEM did not originally manufacture the IC’s they sold.  They received completed devices from Motorola, and remarked them as their own.  This may sound odd, but it served a purpose, it increased SESCOSEM’s market, and allowed Motorola to more easily sell their devices in Europe.  Buying local, to support the domestic industry, was, and continues to be important in Europe, so buying ‘Motorola’ devices, made in the US was less appealing then buying a ‘local’ chip, despite that chip simply being remarked. The agreement called for Motorola to supply
masks and information concerning the 6800 to Thomson-CSF (SESCOSEM parent) for present and future microprocessor products.  Eventually SESCOSEM was able to begin making their own devices at their 2 production facilities: Saint-Égrève , near Grenoble (COSEM site) and Aix-en-Provence (SESCO site).

Sescosem SFF71708J – Another 2708 but made in late 1979, note the switch to the Thomson Semiconductor logo

SESCOSEM also made/sold the various support products for the 6800 series, as well as several EPROM’s, including a clone of the 1702, 2708 and 2716. In mid-1979 SESCOSEM stopped using their own logo, and switched to that of Thomson and in 1982 SESCOSEM was rolled into Thomson Semiconductor, as the French government nationalized and consolidated many industries in an attempt to increase profitability.  Thomson Semiconductor also included Mostek (sold to Thomson in 1985), Silec,  Eurotechnique (French-National Semi joint venture) and EFCIS.  This allowed Thomson to produce Motorola designs, now including the 68000 series of processors. In 1987 SGS of Italy, merged with Thomson to form SGS-Thomson, what is now known today as STMicroelectronics.

While a bit convoluted, this is one reason so many companies manufactured Motorola products.  This helped contribute to the world-wide success of Motorola products.  No longer were they only a US product, but a global product, made and sold by global companies.  In a twist of irony, Freescale, the semiconductor portion of Motorola, was purchased by NXP Semiconductors of the Netherlands in 2015, adding yet another brand of 6800 and 68000 processors.  Only a year later however, in October of 2016 Qualcomm, one of the leading makers of cell-phone chipsets, announced that it will be purchasing NXP.  A Qualcomm 68k processor may very well be in our future.

February 3rd, 2016 ~ by admin

The End of the Omega

ST STi5500 - The Original 50MHz Transputer based Omega

ST STi5500 – The Original 50MHz Transputer based Omega

In January ST announced that they would be exiting the Digital Set Top Box (STB) market.  This is a market that they arguably led for the last 20 years, and one that really began with their Omega processor in 1997. The ST Omega processor line, beginning with the STi5500 powered set top boxes, for cable companies, satellite companies, and DVR’s as well as other TV connected devices.  Open up a satellite TV receiver from the last 20 years and you are very likely to find a STi Omega chipset.

The STi5500 was the beginning, and interestingly at its core was a ST20 processor, based on the Inmos Transputer (which ST now owned) from the late 1980’s.  The Transputer was meant to revolutionize computing, making processors so cheap, that they could be embedded into pretty much any other logic device, what today we call an SoC, but in 1985, was a novel idea.  At the time it didn’t really succeed, but ended up seeing its intended use 10+ years later in the Omega.  In the 1980s the Transputer saw speeds of up to 30MHz, int he STi5500 it ran at 50MHz with 2K of I-cache + 2K of Data Cache as well as 2K of SRAM that could be used as data cache.

ST STi5514 - Enhanced 180MHz Omega

ST STi5514 – Enhanced 180MHz Omega

In the early 2000s the Omega was upgraded to a faster ST20 core, eventually hitting 243MHz in the STi5100, now with the caches increased to 8K each, as well as 8K of SRAM.  This was getting to be the limit of the ST20 Transputer core.  ST needed a core that could support higher speeds running such things as Java and Windows CE amongst other things, as well as support the higher resolutions and audio quality requirements.

ST handled this is in two entirely different ways.  First they licensed the SH-4 32-bit RISC core from Hitachi, a rather surprising move but STBs was not a market Hitachi was in, so it was in both companies best interest.  ST also was working on their own new core to replace the ST20, and they had help, from a very surprising partner.

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May 21st, 2013 ~ by admin

MCU of the Day: ST7 Family: 68HC05 Reborn

8-bit 8MHz w/ ADC and 16K EPROM

8-bit 8MHz w/ ADC and 16K EPROM

One of the most well known microcontroller families is the Intel MCS-51.  It was introduced in 1980 and is still being made in many many forms.  It, however, is not the only popular 8-bit microcontroller.  Motorola made many microcontroller versions of the famous 6800 CPU.  Namely the MC6804 and the still in production 68HC05 series.

ST, which was formed by the merger of SGS of Italy, and Thomson of France, also makes a wide range of 8-bit microcontrollers which are very popular and widely used.  The ST7 microcontroller is a 8-bit Von Neumann architecture (shared address/data bus) MCU.  It is a serial accumulator design (so all operations occur in the accumulator, rather than in a wide set of registers like the 8051).  The ST7 was introduced in the early 1990’s as an upgrade to the ST6 Family of microcontrollers.  The ST7 added more high level programming support, and better interrupt handling.  The ST7 provides higher performance then many competing architectures and in various performance tests such as IRQ handling, returns, instruction execution times etc, it even beats the venerable 80C51.

Both the ST6 and ST7 families are based on the Motorola MS680x microcontroller family.  The ST6 closely resembles the 6804 and the ST7 is upwards code compatible with the MC68HC05 (assembly level translators exist to port the raw code).  The ST7 has 63 instructions and the 6805 has 62 (depending on version).  It is not an uncommon practice for one MCU to be based off, or even compatible with another.  It provides more familiarity for programmers and design engineers.  What really sets a MCU apart is the peripherals that surround the core, and its operating parameters.  The ST6 and ST7 are both highly respected for their ESD protection and high noise immunity.  These features were both carried over into the ST8M family that was introduced in 2008 to replace the aging ST7.  The ST7 can be found in many applications such as automotive  appliance control, motor control, and other embedded systems that most people forget are run by a processor.

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