P306/P307 Integrator’s Guide
Chapter 2-Board Overview
Page 20 of 39
1PPS Timing Signal
The one pulse per second (1 PPS) timing signal is used in applications where devices require time
synchronization.
The 1 PPS signal is 3.3 V CMOS, active high with rising edge synchronization. The 1 PPS signal
is capable of driving a load impedance greater than 10 kΩ in parallel with 10 pF. The pulse is
approximately 1 ms.
Event Marker Input
A GNSS solution may need to be identified at a particular instance, not synchronized with GNSS
time depending on the application, such as indicating to the GNSS receiver when a photo is taken
from a camera used for aerial photography.
The event marker input is 3.3 V CMOS, active low with falling edge synchronization. The input
impedance and capacitance is higher than 10 kΩ and 10 pF respectively, with a threshold of lower
than 0.7 V required to recognize the input.
Grounds
You must connect all grounds together when connecting the ground pins of the P306/P307. Refer
to Table 2-2 through Table 2-3 for pinout ground information for the P306/P307.
Speed Radar Output
The following two pins on the P306 provide access to the Speed Radar option.
Speed Radar Pulse
- Outputs a square wave with 50% duty cycle. The frequency of
the square wave varies directly with speed. 97 Hz represents a speed of 1 m/s (3.28
ft/s).
Speed Radar Ready Signal
- Indicates when the speed signal on the
Speed Radar
Pulse
pin is valid. In static situations, such as when the vehicle has stopped, the
GNSS position may still have slight variations from one moment to the next. During
these instances, the signal on the
Speed Radar Ready Signal
pin is ‘high’ or +Vcc,
indicating the speed coming out of the
Speed Radar Pulse
pin is erroneous and not
truly indicative of the GNSS receiver’s actual speed.
Therefore, it should not be
referred to or be used.
Once the vehicle starts moving again and meets a minimum
threshold speed, the output on the
Speed Radar Ready Signal
pin will go ‘low,’
indicating valid speed information is present on the
Speed Radar Pulse
pin.
Table 2-4 provides the location of the Speed Radar Pulse and Speed Radar Ready Signal on the
P306/P307.
Note:
Each signal pin can offer only 1 mA of current and is active low. Since 1 mA of current may be
inadequate for the application, you may want to transistor-buffer these signals to provide more
current capacity for acceptable LED luminance.
Summary of Contents for P306
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