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PECIFICA TION
Z86E21
CMOS Z8
®
OTP
MICROCONTROLLER
GENERAL DESCRIPTION
The Z86E21 microcontroller (MCU) introduces the next
level of sophistication to single-chip architecture. The
Z86E21 is a member of the Z8 single-chip microcontroller
family with 8 Kbytes of EPROM and 236 bytes of general
purpose RAM.
The Z86E21 is a pin compatible, One-Time-Programmable
(OTP) version of the Z86C21. The Z86E21 contains 8
Kbytes of EPROM memory in place of the 8 Kbyte of ROM
on the Z86C21.
The MCU is housed in a 40-pin DIP, 44-pin Leaded Chip-
Carrier, or a 44-pin Quad Flat Pack, and is manufactured
in CMOS technology. The ROMless pin option is available
on the 44-pin versions only. The MCU can address both
external memory and preprogrammed ROM which en-
ables this Z8 microcomputer to be used in high volume
applications or where code flexibility is required.
Zilog’s CMOS microcontroller offers fast execution, effi-
cient use of memory, sophisticated interrupts, input/output
bit manipulation capabilities, and easy hardware/software
system expansion along with low cost and low power
consumption.
The Z86E21 architecture is based on Zilog’s 8-bit
microcontroller core. The device offers a flexible I/O
scheme, an efficient register and address space structure,
multiplexed capabilities between address/data, I/O, and a
number of ancillary features that are useful in many indus-
trial and advanced scientific applications.
The device applications demand powerful I/O capabilities.
The Z86E21 fulfills this with 32-pin dedicated to input and
output. These lines are grouped into four ports. Each port
consists of eight lines, and is configurable under software
control to provide timing, status signals, serial or parallel
I/O with or without handshake, and an address/data bus
for interfacing external memory.
There are three basic address spaces available to support
this wide range of configuration: Program Memory, Data
Memory and 236 General-Purpose registers.
To unburden the program from coping with real-time
problems such as counting/timing and serial data commu-
nication, the Z86E21 offers two on-chip counter/timers with
a large number of user selectable modes, and an asyn-
chronous receiver/transmitter (UART) (see Functional Block
Description).
In ROM Protect Mode, the instructions LDC, LDCI, LDE
and LDEI are disabled when reading address locations
%0000 to %1FFF.
Notes:
All Signals with a preceding front slash, "/", are active Low, e.g.:
B//W (WORD is active Low); /B/W (BYTE is active Low, only).
Power connections follow conventional descriptions below:
Connection Circuit Device
Power V
CC
V
DD
Ground GND V
SS
DC-2964-10
PRODUCT RECOMMENDATIONS
Zilog recommends the following programming equipment for use with this One-Time-Programmable product:
Recommended Revision Level
Device Zilog Support Tool Hardware Software
Z86E21 Z86C1200ZEM ICEBOX
™
Emulator* (*Does not support 4K/8K option.) B 1.5
Z86E21 Data I/O 3900 Programmer* (*Does not support option bits.) 1.1
Z86E21 Data I/O Unisite Programmer* (*Does not support option bits.) 3.7
Some non-Zilog programmers may have different pro-
gramming waveforms, voltages and timings and not all
programmers may meet the programming requirements of
Zilog's One-Time-Programmable products.
If difficulty is encountered in programming a Zilog OTP
product, please contact your local Zilog sales office.
