ZED-F9K - Integration manual
than once per second, and polling data only when data is available, determined by the TX_READY
pin becoming active.
3.5.6 EXTINT
EXTINT is an external interrupt pin with fixed input voltage thresholds with respect to VCC. It can
be used for functions such as accurate external frequency aiding and on/off control. Leave open if
unused, this function is disabled by default.
3.5.7 WT and DIR inputs
ZED-F9K pin 22 (WT) is available as a wheel-tick input. Pin 23 (DIR) is available as a direction input
(forward/reverse indication).
By default the wheel tick count is derived from the rising edges of the WT input.
The WT input may be configured to use both the rising and falling edges of the wheel tick signal. To
use both edges, the wheel tick pulses shall have approximately 1:1 mark:space ratio regardless of
speed. The minimum recommended pulse width is 10 us.
For optimal performance the wheel-tick resolution should be less than 5 cm.
The wheel-tick input shall change frequency linearly with respect to the change in vehicle speed.
When the vehicle is stationary, there shall be no wheel-tick pulses at the WT input. This is especially
important at system shutdown and startup.
Performance may be affected if there are wheel-ticks on the WT pin while the vehicle is
stationary.
The DIR input shall indicate whether the vehicle is moving forwards or backwards.
By default, the DIR pin-polarity is automatically initialized once the vehicle has reached required
minimum speed of
30 km/h
. The DIR pin polarity can also be configured with the CFG-SFODO-
DIR_PINPOL key.
Incorrect operation may occur if WT input is used without a matching DIR input.
Alternatively, the vehicle WT (or speed) and DIR inputs can be provided via one of the communication
interfaces with UBX-ESF-MEAS messages. In this use case, the WT pin can be configured as
EXTINT1 to provide a time-mark for the UBX-ESF-MEAS messages. The DIR pin can be left open.
Do not exceed the maximum voltage of 3.6 V at the WT and DIR inputs.
For more information, see the ZED-F9K Interface description [
3.5.8 GEOFENCE_STAT interface
The ZED-F9K provides a GEOFENCE_STAT pin that indicates the current geofence status as to
whether the receiver is inside any of the active areas.
This feature can be used for example to wake up a sleeping host when a defined geofence condition
is reached. It is possible to configure up to four circular areas as geofence locations. Once configured,
the receiver continuously compares its current position with the preset geofenced areas.
For more information in this functionality, see
The receiver toggles the assigned pin according to the combined geofence state.
There are three possible outcomes for each geofence:
UBX-20046189 - R01
3 Receiver functionality
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Early production information
