APEX ORIN NX II SYNC IO Interface#
DP9 Pin Definition for SYNC_IO:
Pin |
Signal |
|---|---|
1 |
SYNC_IN_A |
2 |
SYNC_OUT_A |
3 |
NC |
6 |
GND |
7 |
GND |
8 |
GND |
Pin |
Specification |
|---|---|
SYNC_OUT_A |
5V |
SYNC_IN_A |
(Logic High 4.5V-12V, Logic Low 0V-2V) |
SYNC_IN Usage#
Hardware Connection#
SYNC IN is mainly used to receive the PPS signal from a GPS device. Together with GPRMC messages received over the serial port, this allows an external GPS device to provide system time synchronization.
Usage#
SYNC IN Synchronization Mode#
The device supports SYNC IN synchronization signals.
A sensor supporting SYNC IN synchronization generates a pulse when it starts sampling. The device receives the pulse through the SYNC_IN pin and records its rising-edge time. After sampling is complete, the device associates that time with the data returned by the sensor as the data timestamp. The system thereby obtains the sensor sampling time in its own time base and completes synchronization.
SYNC IN Synchronization Diagram (10Hz)
Synchronization Verification: In Ubuntu, print the timestamp of the pulse received through SYNC_IN and compare it with the system time when the sensor data frame is received (ros::time::now). A difference of less than 100ms indicates that SYNC IN is working.
SYNC_OUT Usage#
Hardware Connection#
SYNC OUT is mainly used to trigger external cameras at a fixed frequency.
Usage#
SYNC OUT Synchronization Mode#
The device can output a 1–30Hz pulse signal with a pulse width of 5ms through the Sync out pin to trigger an external sensor to start sampling. The device also records the pulse’s rising-edge time. After sampling is complete, the device associates that time with the data returned by the sensor as the data timestamp. The system thereby obtains the sensor sampling time in its own time base and completes synchronization.
SYNC OUT Synchronization Diagram (25Hz)
The device also provides Sync out synchronization through the GMSL interface. See the GMSL camera chapter for details.
Synchronization Verification: Configure the sensor for external trigger synchronization and capture data with ROSbag to verify whether the sensor trigger frequency matches the value configured in sync.cfg. A difference of less than 1Hz indicates that Sync out is working.
Data Transfer Time Analysis
Test description: Set the Sync out frequency to 10Hz and measure the interval (transfer time) from the rising edge of the device’s Sync out signal to reception of the video frame by the device.
IO Frame Transfer Timing Diagram
Frame Transfer Time Test Results
The measured average frame transfer time was 65.70ms.