Z8FS021 Datasheet, PDF (46/68 Pages) Zilog, Inc. – Select from an assortment of lenses and pyroelectric sensors to best fit your application

ZMOTION^® Intrusion Detection
Product Specification
38
EM Transient Detected (Bit 0)
EM Transient Detected on PIR Signal; set by the PIR Engine; cleared by the application.
• This bit indicates if the Engine has detected a transient on the PIR signal. This event is provided to
the user application to indicate that an EM transient event has occurred and associated motion
event(s) may have been suppressed by the Engine. This bit is does not have to be read for normal
operation and is provided as status only. The application must clear this bit after it has been read.
Bit
Field
Control
Address
Table 18. PIR Advanced Status/Control Register 1
(ePIR_ASC1)
7
6
5
4
3
2
1
0
White Light Debounce
White Light Scan Rate
R/W
R/W
F1H
White Light Debounce (Bits 7–4)
White light debounce time; controlled by the application.
• This value determines the amount of debounce applied to the White Light detection. White Light
Debounce is the number of sequential WL samples above the threshold value set in the PIR Status/
Control Register 2 required to consider it as a WL event. Larger numbers result in more stable White
Light detection at the cost of slower White Light response.
0 = Internal V_REF selected.
1 = External V_REF selected.
White Light Scan Rate (Bits 3–0)
White light (LED) scan rate; controlled by the application – see the equation that follows.
• This value determines the rate (in seconds) at which the White Light signal is sampled. WL scan is
performed at a maximum rate of once every 5 PIR constructed samples when this value is set to 0.
The PIR constructed sample time is determined by the PIR Sample Size Register. Each increment of
1 to the White Light Scan Rate value adds 5 constructed samples to the time between White Light
scans.
Use the following equation to determine the White Light scan rate, in seconds:
1280*ePIR _ Sample _ Size  4873*White _ Light _ Scan _ Rate 1
System _ Clock _ Frequency
Larger values create a slower sample rate, which results in slower White Light response.
Smaller numbers will increase White Light event response at the cost of potentially
degrading motion detection.
PS028806-0315
Advanced API Register Set