Z8FS021 Datasheet, PDF (61/68 Pages) Zilog, Inc. – Select from an assortment of lenses and pyroelectric sensors to best fit your application

ZMOTION^® Intrusion Detection
Product Specification
53
Z8FS021xHJ20EG (28-Pin)
Examples of single and dual pyro circuit designs employing the 28-pin ZMOTION Intru-
sion Detection MCU are described in this section.
Single Pyroelectric Sensor
Figure 10 shows an example circuit for the 28 pin device of the ZMOTION Intrusion
Detection MCU with a single pyroelectric sensor. The interface to the pyroelectric sensor
is via the dedicated input ANA2 (pin 1). V_REF (pin 3) must be externally tied to ANA3
(pin 4). This is considered Internal V_REF and bit 7 of PIR_ASC0 is set to '0' since it is
being generated by the internal voltage reference. If an externally generated voltage refer-
ence is to be used, tie it directly to ANA3 (pin 4) and V_REF, (pin 3) and set bit 7 of
PIR_ASC0 to '1'.
The status LED is driven by pin 28 (PB1/ANA1) which is normally configured as a GPIO
by the application to control the state of the LED. When White Light Detection is enabled,
the PIR Engine automatically reconfigures this pin to an ADC input to perform the neces-
sary ADC conversion and returns it to a GPIO when done.
Pin 22 is dedicated as the Debug pin and is connected to pin 4 of the Debug Header. Pin 21
is set up for the Reset function, but can also be used as PD0 (general purpose I/O) as the
application requires. Pull-up resistors (10K) are provided on the Debug and Reset signals
as required for the Debug interface. All other signals can be used as required.
The power supply design remains available to application requirements.
PS028806-0315
Appendix A. Example Application Schematics