Z8FS040 Datasheet, PDF (38/56 Pages) Zilog, Inc. – ZMOTION Detection and Control Family Featuring Zilog’s PIR Technology

ZMOTION^TM Detection and Control Family
Product Specification
Using a value less than the value in the PIR Sensitivity Register will result in no motion detection.
PIR Debounce Batch Size Register (ePIR_Debounce_Batch)
Bit
7
6
5
4
3
2
1
0
Field
PIR Debounce Batch Size
Control
Read/Write
Address
F7H
Debounce Batch Size (Bits 0-7)
Controlled by application
This register determines the number of consecutive out-of-window samples required in order to consider
the sequence a valid debounce count. The field works as a mask. Increasing the mask size (i.e. more
bits set to 1) will increase the noise immunity of the engine but result in lower sensitivity to subtle motion
signals.
Valid values are 01h, 03h, 07h, 0Fh, 1Fh, 3Fh, 7Fh, and FFh.
PIR Transient Sensitivity Level (ePIR_Transient_Sense)
Bit
7
6
5
4
3
2
1
0
Field Reserved
PIR Transient Sensitivity
Control
0
Read/Write
Address
F8H
Transient Sensitivity (Bits 0-6)
Controlled by application
This register determines how sensitive the transient detection part of the engine is to sudden changes in
the PIR signal. A lower number makes the engine more sensitive, at the cost of potential rejection of
large signal motion (ex. warm target very close to detector).
The valid range is 0 (disabled) to 64h.
PIR Noise Sensitivity Level (ePIR_Noise_Sense)
Bit
7
6
5
4
3
2
1
0
Field
Control
Address
Reserved
0
PIR Noise Sensitivity
Read/Write
F9H
Noise Sensitivity (Bits 0-6)
Controlled by application
This register determines how sensitive the noise detection part of the engine is to random noise in the
PIR signal. A lower number makes the noise detector more sensitive, at the cost of potential rejection of
small-signal motion (ex. Small delta between ambient and target temperature or distant target). The
valid range is 0 (disabled) to a maximum value determined by the Window Size selected in the PIR
Advanced Status/Control Register 2.
Window Size Max PIR Noise Sensitivity Value
Small
0Ch
Typical Value
08h
PS028506-1110
PRELIMINARY
33