Hi, I’m using an Arducam B0224 1MP OV9281 130° monochrome NoIR global shutter camera (the board says UC-788 Rev B) on a Raspberry Pi Zero v1.3. I need to synchronize the camera shutter with an external flash. On the UVC version of the OV9281 the strobe signal is high while the shutter is open, but on this unit the FSTROBE pin always reads 0V. I was following this guide about feeding an external trigger into the XVS pin: External Trigger Mode - Arducam Wiki. Two things I can’t figure out: is there a command I need to run to enable the signal on the FSTROBE pin, and what is the GPO pin actually for / how do I use it?
Thanks for the details. Can you confirm the exact model and your setup, and let me know what you’ve already tried so far?
Sure. The camera is the Arducam B0224 1MP OV9281 130° monochrome NoIR global shutter for Raspberry Pi, M12 S-mount (AC2-202240), running on a Raspberry Pi Zero v1.3. I’ve connected the FSTROBE and GPO pins to an oscilloscope and there’s no voltage on either of them while the camera is capturing. I’ve also searched around online quite a bit but couldn’t find anything useful about enabling those pins on this board.
This camera uses the Raspberry Pi official driver, and the hardware itself should support the FSTROBE pin. The question is really whether the native ov9281 driver enables that pin. It’s uncertain at this point that it does.
So is there any way to actually turn it on? The documentation makes it seem like the pin should be there and usable.
There isn’t a documented command to enable FSTROBE from the stock driver. For this board you should keep using the Raspberry Pi official driver. I’ve sent you the contact details for requesting a customized driver privately, if that’s something you want to pursue.
Got it, thanks. Are there any other drivers I could use to enable this FSTROBE pin? It’s still sitting at 0V and I really need it for flash/shutter synchronization.
I checked the hardware details on this one. The camera does not include a pivariety chip.
What does that mean for driver options exactly?
Because there’s no pivariety chip, the camera can only use the Raspberry Pi native camera driver. The pivariety-enabled drivers are not available for this board. So there are no additional driver options for enabling FSTROBE beyond what the native ov9281 driver provides.
So effectively there’s no alternative driver that would let me turn the strobe signal on?
Correct. The lack of a pivariety chip restricts the ability to enable the FSTROBE pin through non-native drivers. You’re limited to the Raspberry Pi native driver, and whether FSTROBE can be enabled depends on what the native ov9281 driver exposes. At this point there’s no confirmed way to enable it beyond that. I’ve sent you the private details for requesting a customized driver if you need to go that route.