Z8FS021 Datasheet, PDF (26/68 Pages) Zilog, Inc. – Select from an assortment of lenses and pyroelectric sensors to best fit your application

ZMOTION^® Intrusion Detection
Product Specification
18
28-Pin Device
Pin 1 (ANA2) is reserved as the analog ADC input from the pyroelectric sensor. In Single
Pyro Mode, Pin 4 (ANA3) must be externally tied to V_REF on Pin 3 (PB5/ V_REF). PB5 will
be configured as V_REF output by the PIR Engine when it is enabled.
In Dual Pyro Mode, which supports 2 pyroelectric sensors, Pin 4 (ANA3) is used for the
second sensor. In this mode the Pin 3 V_REF signal is not connected externally to any
other ADC inputs and is therefore available to the application (PB5/V_REF).
Hardware Connection Requirements
This section describes the required external hardware connection for the ZMOTION MCU
Series. See Appendix A. Example Application Schematics on page 49 for example sche-
matic diagrams showing these connections.
Pins are automatically configured to their required function when the PIR Engine is initial-
ized via the EPIR_INIT macro. The device can be operated in Single Pyro Mode when
supporting one pyroelectric sensor or in Dual Pyro Mode when supporting two pyroelec-
tric sensors. Both of these modes can be operated in Normal or Low Scan Rate modes.
Depending on the application, there can be up to four connection requirements supporting
these modes: one for each of two PIR sensors, one for the ADC and one for the White
Light Detection and Status LED. A description of each of these elements follows in this
section. For a broader description of the White Light Detection component, see the White
Light Detection section on page 19.
Pyroelectric PIR Sensor #1
The signal from the PIR sensor is connected directly to the ANA2 input of the ADC. The
ADC is configured for differential buffered mode by Zilog’s PIR technology. The sensor
signal should be connected directly to the ADC input with no additional signal condition-
ing circuitry unless specified by the pyroelectric sensor manufacturer.
ADC V_REF
The on-chip V_REF is configured for 1V of nominal voltage. The PIR Sensor signal is con-
nected to the positive (+) differential input of the ADC (ANA2), and the V_REF signal is
connected to the negative (–) differential input (ANA3). The 8-pin device provides an
internal connection from V_REF to ANA3 to support this configuration; therefore, no exter-
nal hardware connection is required. The 20- and 28-pin devices require an external con-
nection from the V_REF output signal to the ADC negative (–) (ANA3) input.
Pyroelectric PIR Sensor #2
In Dual Pyro Mode, the ADC is still used in differential buffered mode (i.e., as is true for
Single Pyro Mode). The signal from the second PIR sensor is connected to ANA3. The
PS028806-0315
Hardware Connection Requirements