Z8PE003 Datasheet, PDF (24/48 Pages) Zilog, Inc. – FEATURE-ENHANCED Z8PLUS 1K ROM ONE-TIME PROGRAMMABLE (OTP) MICROCONTROLLER

Z8PE003
Z8Plus OTP Microcontroller
CLOCK
The Z8Plus MCU derives its timing from on-board clock
circuitry connected to pins XTAL1 and XTAL2. The clock
circuitry consists of an oscillator, a glitch filter, and a di-
vide-by-two shaping circuit. Figure 12 illustrates the clock
circuitry. The oscillator’s input is XTAL1 and its output is
XTAL2. The clock can be driven by a crystal, a ceramic res-
onator, LC clock, or an external clock source.
By selecting the RC OSCILLATOR option in the graphical
user interface (GUI), the circuit may instead be driven by
an external Resistor and Capacitor (RC) oscillator. Figure
13 illustrates this configuration. This design is limited to no
more than 4 MHz to restrict EMI noise.
Note: The reduced drive strength of this configuration also al-
lows the clock circuit to use a micropower-type crystal
(also known as a tuning fork) without reduction resis-
tors.
ZiLOG
Note:
4 MHz max.
Glitch
Filter
÷2
XTAL2
R
XTAL1
C
V_SS Pin
Figure 13. Z8Plus in RC Oscillator Mode
XTAL1
XTAL2
Glitch
Filter
÷2
÷4
Machine
Clock (SCLK)
(5 cycles
per in-
struction)
Timer
Clock (TCLK)
÷8
WDT
Clock
Figure 12. Clock Circuit
24
PRELIMINARY
DS007500-Z8X0399