Zilog Z8 processor
Zilog Z8 (Super-8 family)

The Zilog Z8 is a microcontroller architecture, originally introduced in 1979, which today also includes the Z8 Encore!, eZ8 Encore!,[1] eZ8 Encore! XP, and eZ8 Encore! MC families.

Signifying features of the architecture are up to 4,096 fast on-chip registers which may be used as accumulators, pointers, or as ordinary RAM. A 16-bit address space for between 1 KB and 64 KB of either OTP ROM or flash memory are used to store code and constants, and there is also a second 16-bit address space which may be used for large applications.

On chip peripherals include A/D converters, SPI and I²C channels, IrDA encoders/decoders etc. There are versions with from 8 up to 80 pins, housed in PDIP, MLF, SSOP, SOIC and LQFP packages. The eZ8 Encore! series can be programmed and debugged through a single pin serial interface.

The basic architecture, a modified (non-strict) Harvard architecture, is technically very different from the Zilog Z80. Despite this, the instruction set and assembly syntax are quite similar to other Zilog processors: Load/store operations uses the same LD mnemonic (no MOV or MOVEs), typifying instructions such as DJNZ, are the same, and so on.

An IDE named Zilog Developer's Studio (ZDS) can be downloaded from Zilog's website including an assembler. The edition of ZDS II targeting Z8 Encore! and newer derivatives also includes a free compiler claiming ANSI C89 compliance.

Primary competitors include the somewhat similar[2] Microchip PIC family, and all the Intel 8051 descendants. Also more traditional "von Neumann based" single chip microcontrollers may be regarded as competitors, such as the 6800/6809 based Motorola 68HC11, the Hitachi H8 family, and Z80-derivatives, such as Toshiba TLCS-870, to name just a few.

Product lineEdit

  • ROMless: Models without integrated ROM.
  • ROM: Models with integrated ROM.
  • BASIC: Models with integrated BASIC interpreter and debugger in ROM.
  • OTP: Models with integrated OTP ROM.
  • Low Voltage: Working voltage run as low as 2V.
  • GP: General purpose microcontroller.
  • Encore!: Integrated flash-based memory.
  • Encore! XP: Encore! with sensors.
  • Encore! MC (Motor Control): Motor control applications.


A free software (GPLv3) Z8 emulator written in Java for Linux, Windows and OS X can be downloaded here: http://www.jens-mueller.org/jtcemu/download.html

Second sourcesEdit


  1. ^ The "Encore!" products contains the newer eZ8 core which is 2-3 times as clock cycle efficient as the original Z8 core.
  2. ^ The PIC and the 8051 are using Harvard architectures as well, but in a more rigid manner.


  • Grehan, Rick (September 1994). "Processors Proliferate". Byte.

External linksEdit