Syncing multiple CSI cameras

Autonomous Machines Jetson & Embedded Systems Jetson TX2
1

Jetson TX2 has an output called CAM_VSYNC - a dedicated output for syncing multiple cameras?!
Where can I find info about this pin - how to program and control it?

2

@christian
This pin just a GPIO pin only. If you want to design sync multiple camera you have to consult with sensor vendor.

3

Hi ShaneCCC,

Thanks for your prompt reply. I am looking for an output from the TX2 Jetson camera controller, or a perihperal that could output a sync pulse at a programmable rate - to sync two cameras with external trigger inputs.

The naming of the pin “CAM_VSYNC” gives the impression that this pin could be used in such applications. If this pin is just a GPIO - why is it named CAM_VSYNC? As a hardware designer I am unfortunately not very familiar with the Tegra CPU inside the TX2.

Is there a timer or a PWM that could provide a [b]stable /b pulse output for syncing cameras in 3D stereo applications? If the aswer is yes - at wich pin is such a signal available?

If the answer is no - I am a little puzzled - isn’t the TX2 intended for 3D stereo imaging and therefore should have an internal sync generator that could be used?

Cannot release the design before this detail is confirmed. Grateful for your support.

Christian

4

It’s just a name for tegra side. The most important things is sensor have this function.

5

@ShaneCCC

I have two camera chips in the design that has trigger inputs. This is a custom design. The principle is very clear how do the syncing.

NOW - I just need to know - does the TX2 have an output that can be used for this purpose - or not?

To sync the external cameras a stable pulse at a programmable frequency between 10Hz…60Hz is needed. Is there an internal timer or PWM modulator that could be used - if the CSI camera control system does not include one? And to which pin can this signal be outputted?

I believe this is a recurring and important question for anyone trying to sync multiple cameras using the TX2.

Can you put me in contact with someone that has this detailed knowledge? This issue is very urgent.

Christian

1 Like
6

There’s no any HW output for sync sensor on tegra. As my experience the sensor should have a sync pin connect to each other and program it as master and slave for sync.

7

Thanks. There are other means of generating a sync signal, even withing Jetson. The GPIO pin on TX2 called “CAM_VSYNC” is a little misleading… mildly put.

8

Hi,

I understand you are developing custom hardware but for reference D3 Engineering provides Jetson TX2 systems capable of providing this camera synchronization input. We use a small FPGA connected to the Jetson in order to generate waveforms for synchronization. You can reference our block diagram here:

Regards,
Jason

9

Hi Jason,

Many thanks for your input and the link to your very nice product. In my case it would not be practical to use the cameras in master-slave fashion. Also considered a small FPGA but I found a way to generate stable low frequency pulses from the Jetson and will test that feature first.

Christian

10

Hi Christian,
Can you reveal how you got a stable pulse out of the TX2?