Z8FS021 Datasheet, PDF (24/68 Pages) Zilog, Inc. – Select from an assortment of lenses and pyroelectric sensors to best fit your application

ZMOTION^® Intrusion Detection
Product Specification
16
UART
8-Pin Device
/CTS0 is configured as ANA2 to support the signal
input from the Pyroelectric sensor. It is therefore not
available to the user application. The UART is still
able to function correctly without /CTS when CTSE in
the U0CTL0 Register is set to 0.
20-Pin Device All external UART functions are available for the user
application.
28-Pin Device All external UART functions are available for the user
application.
Oscillator Control
All devices can be operated with the internal 5.54 MHz IPO. For applications that require
more processing power or a more accurate time base, an external crystal oscillator or
ceramic resonator can be used.
When using the 8-pin device, external oscillator support is limited to Single Pyro Mode
only, because ANA3 (the ADC input for a second pyro sensor) is multiplexed with X_OUT.
The 20- and 28-pin devices can be operated with an external oscillator in both Single and
Dual Pyro modes.
Caution: Do not operate at frequencies lower than the IPO frequency while the PIR Engine is en-
abled or motion detection performance will be degraded.
No other changes or limitations are placed on oscillator control functions by the PIR
Engine.
Flash Memory
The control registers associated with Flash memory are all available to the application.
The PIR Engine uses the value programmed into the Flash Frequency registers (FFREQ)
to determine the required sample rate of the ADC and other functions. The Flash Fre-
quency High (FFREQH) and Flash Frequency Low Byte (FFREQL) registers must be pro-
grammed prior to initializing the PIR Engine. These two registers combine to form a 16-
bit value, FFREQ. This value is the System Clock Frequency in KHz and is calculated
using the following equation.
FFREQ[15:0] = {FFREQH[7:0],FFREQL[7:0]} = (System Clock
Frequency)/1000
PS028806-0315
Peripherals