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Last edited: 02/25/98 by wsw
During my career as hobbyist/student/developper in electronics I did several designs using Zilog CPUs and controllers. I started 1978 by building my first ECB based computer using the Z80 CPU. It was upgraded and modified several times (one of the advantages of a modular design) and I still have it in workable condition. Here are some photos.
This first machine was designed after a system made by a german manufacturer called ELZET80. Later I met one of the owners of this company (Walter Giessler) at an electronics fair and this led to a long relation- and friendship during which I designed some stuff for them (in the (now gone?) MOPS series), like the StepperMOPS.
I found the MOPS series a very clever design idea: There were several CPU kernels which had contact rows on two sides. Different I/O modules could then be matched to either side during manufacture of the PCB. If a customer needed a controller board with a new interface, only this part had to be developped and he could get his boards rather quickly.
When I designed the MOPS C kernel around the TMPZ84C015 (a Z80 CPU with PIO, SIO, CTC, clock generator and watchdog on one chip), I did 3 different designs. ELZET wanted the biggest of them (with MMU) and so I offered the smallest one to the german computer magazine c't and wrote an article about it. It was published in issue 8/88 under the name CEPAC-80 SMD. An additional article in the next issue was about a generic monitor program, modified for the CEPAC.
I also did a MOPS kernel design using a Z280. Unfortunately this processor remained rather unknown.
Often there is a need for a small computer for control and other small tasks where a full blown modular system is rather overkill. Even the chip manufacturer recognized this and brought out nice series of microcontrollers. One of the first was Zilogs Z8. Of course I too used it for several Z8 projects.
Long after other manufacturers (e.g. Hitachi) built Z80 derivates (like the HD64180 which later was adopted to become the Z180) even Zilog realized that there was a need for a faster Z80 CPU and brought out the Z280. I did a design for a new MOPS kernel using this CPU. Unfortunately it never went into production (they made the very nice TSM series instead), but here you can see the prototype.
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Last edited: 02/25/98 by wsw