U880


The U880 is an 8-bit microprocessor that was manufactured by VEB Mikroelektronik "Karl Marx" Erfurt in the German Democratic Republic. Production of the U880 started in 1980 at VEB Funkwerk Erfurt. The U880 is an unlicensed clone of the Zilog Z80 microprocessor. It is not, however, a direct copy of the Zilog's Z80. Differences include not setting the CY flag for the command.

Processor variants

The U880 was manufactured in NMOS technology and encased in a plastic DIL40 package with a pin spacing of 2.5 mm.
Temperature rangeClock rateDesignations
0 °C to 40 °C1 MHzUD880D, UB880D S1
0 °C to 70 °C2.5 MHzU880D, UB880D, 80-CPU
0 °C to 70 °C4 MHzUA880D, 80A-CPU
0 °C to 70 °C8 MHzU880DC08, Thesys Z80H
−25 °C to +85 °C2.5 MHzVB880D

The military version of the U880 has an additional "MEK 4" marking.

Support chips

VEB Mikroelektronik "Karl Marx" also manufactured a number of support chips for the U880. The prefixes UA, UB, VB, 80, and 80A correspond to the same temperature ranges and clock rates as for the processor variants above. Likewise, the suffix S1 indicates the out-of-spec, hobbyist version.
DesignationInternational equivalentDescription
U855D, UA855D, UB855D, UD855D, VB855D, UB855D S1, 80-PIO, 80A-PIOZilog Z80 PIOparallel input/output
U8560D, UA8560D, UB8560D, VB8560D, UB8560D S1, 80-SIO/0, 80A-SIO/0Zilog Z80 SIO/0serial input/output
U857D, UA857D, UB857D, VB857D, UB857D S1, 80-CTC, 80A-CTCZilog Z80 CTCcounter/timer circuit
UA858D, UB858D, UB858D S1, 80-DMA, 80A-DMAZilog Z80 DMADMA controller
U8561D, UB8561DZilog Z80 SIO/1serial input/output
UA8563D, UB8563D, VB8563D, UB8563D S1, 80-DART, 80A-DARTZilog Z80 DARTdual asynchronous receiver/transmitter
U8272D04, U8272D08Intel 8272floppy-disk controller
U82530DC04, U82530DC06Zilog SCCserial communications controller
U82536DC04Zilog CIOcounter/timer and parallel input/output
U82720DC02, U82720DC03, U82720DC04Intel 82720graphics display controller

Applications

The U880 was by far the most widely used microprocessor in the German Democratic Republic. Examples are:
At the time the U880 was the most advanced 8-bit processor available in the Eastern Bloc. Only clones of the Intel 8080 were manufactured in Poland, Czechoslovakia, Hungary, Romania, and the Soviet Union. As the Z80 replaced the Intel 8080 in the West, the U880 was used throughout the Eastern Bloc. Examples are:
Following the example of Zilog where the Z80 was succeeded by the 16-bit processors Z8001 / Z8002, VEB Mikroelektronik "Karl Marx" produced the U8001 / U8002. And just like its Western counterpart, the U8001 / U8002 saw far less use than the U880. When MS-DOS emerged as the dominant operating system for personal computers, in the Eastern Bloc the only available clone of the Intel 8086 was the Soviet K1810VM86. VEB Mikroelektronik "Karl Marx" then proceeded to develop a clone of the Intel 80286, the U80601. Furthermore, a CMOS version of the Z80 was developed with the designation U84C00. Due to the economic changes following the German reunification in 1990, both projects did not proceed beyond pilot production. VEB Mikroelektronik "Karl Marx" was privatized in 1990 under the name ERMIC GmbH, a large part of which became Thesys Gesellschaft für Mikroelektronik mbH in 1992. Both ERMIC and Thesys continued to manufacture the NMOS version of the U880, ERMIC still with the MME name and logo, Thesys under its new name. A die shrink chip with the marking U880/6 had been developed in 1990 and went into production some time after that. The smaller chip allowed clock rates up to 8 MHz for the U880DC08 and Thesys Z80H. While Zilog likely could have taken up legal action against the successors of VEB Mikroelektronik "Karl Marx" for copyright infringement, they recruited Thesys as a Zilog distributor instead.
From about 1991 until 1993, bare U880 chips were sold to Russian and Ukrainian companies and packaged there. Initially the U880/5 chip revision was labelled as 80A-CPU and T34VM1. Later integrated circuits with U880/6 chips inside received the official designation KR1858VM1 for the plastic package and KM1858VM1 for the ceramic package. Manufacturers include Angstrem Zelenograd, Kvazar Kiev, and VZPP Voronesh.