Z8FS040 Datasheet, PDF (21/56 Pages) Zilog, Inc. – ZMOTION Detection and Control Family Featuring Zilog’s PIR Technology

ZMOTION^TM Detection and Control Family
Product Specification
Hardware Connection Requirements
This section describes the required external hardware connection for the ZMOTION^TM MCU Series.
Pins are automatically configured to their required function when the PIR engine is initialized via the
EPIR_INIT macro.
See Appendix A for example schematic diagrams showing the required connections.
The device can be operated in Single Pyro mode supporting one Pyroelectric sensor or Dual Pyro
mode supporting two Pyroelectric sensors. Both of these modes can be operated in Normal or Low
Scan Rate modes.
Depending on the application, there can be up to 3 connection requirements supporting these modes:
1. Pyroelectric Sensor (PIR Sensor)
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 conditioning circuitry
unless specified by the pyroelectric sensor manufacturer.
2. ADC V_REF
The on chip V_REF is configured for 1V nominal. The PIR Sensor signal is connected to the ‘+’
differential input of the ADC (ANA2) and the V_REF signal is connected to the ‘-‘ differential input
(ANA3). The 8 pin device has an internal connection from V_REF to ANA3 to support this
configuration therefore no external hardware connection is required. The 20 and 28 pin
devices require an external connection from the V_REF out signal to the ADC ‘-‘ (ANA3) input.
3. Pyroelectric Passive Infrared Sensor #2
In Dual Pyro mode, the ADC is still used in differential, buffered mode (same as Single Pyro
mode). The signal from the second PIR sensor is connected to ANA3. The V_REF signal is no
longer connected to ANA3 (‘-‘ ADC input). The fist PIR sensor is connected to the ‘+’ ADC
input (ANA2) as it is in Single Pyro mode. The V_REF signal is still used internally for the ADC,
but the external pin is unused in Dual Pyro mode.
PS028506-1110
PRELIMINARY
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