Z8FS040 Datasheet, PDF (27/56 Pages) Zilog, Inc. – ZMOTION Detection and Control Family Featuring Zilog’s PIR Technology

ZMOTION^TM Detection and Control Family
Product Specification
MD Suspend (Bit 4)
Motion Detection Suspend
Controlled by Application
Temporarily suspends the PIR engine from running. This puts it in a very low processing overhead state
and can be used when the application requires significant CPU processing power. While suspended,
motion detection is disabled, however to ensure fast recovery from this mode, ADC interrupts still occur
and samples continue to be buffered. When the application clears this bit, suspend mode is exited upon
the next ADC interrupt.
0 = Normal Motion Detection
1 = Suspended Motion Detection
Motion Direction Control (Bit 3)
Motion Direction Control Enable
Controlled by Application
This bit enables directional motion detection. The relative direction of the detected motion is indicated in
bit 2 (Motion Direction) of this same register. When configured as a directional detector (bit 3 set to 1),
direction is indicated in bit 2 as positive or negative relative to the PIR sensor.
0 = Standard Motion Detection Mode. Motion detected in any direction. Motion Direction status bit (Bit 2)
is not valid.
1 = Directional Motion Detection Mode. Motion is detected in any direction; relative direction is indicated
via Motion Direction status bit (Bit 2).
The directional polarity of PIR sensors is arbitrary at the time of manufacturing. Therefore it is necessary
for the user application to calibrate to each individual PIR sensor using a controlled target (i.e. moving in
a known direction) and internally record the polarity to identify which polarity represents that direction.
Motion Direction (Bit 2)
Relative Direction of Last Motion Detected
Controlled by PIR engine
When directional motion detection is enabled, this bit indicates the relative direction of the last motion
detected. When the PIR engine sets the Motion Detected bit in PIR Status Register 0, this bit is set or
cleared to indicate the direction of the motion. The status is latched until the user application clears the
Motion Detected bit.
0 = Last detected motion was negative
1 = Last detected motion was positive
This status bit is undefined when Motion Direction Control is disabled.
Motion Detected (Bit 1)
Motion detected on PIR sensor
Set by PIR engine; cleared by application
This bit indicates that the Engine has detected a motion event. The user application should routinely
check this bit to determine if motion has been detected. This bit is set by the Engine and must be
cleared by the user application.
0 = No motion detected by the Engine
1 = Motion has been detected by the Engine
PS028506-1110
PRELIMINARY
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