Thanks, I managed to bumble through on my own - I’m posting this to help clarify the current info available, in case anyone needs it
One of my cameras turned out to be the new PCB. I guessed at the FSIN pin (correctly! ), here it is:
http://i.imgur.com/cRoUj.jpg
Sadly, after a quick look, I couldn’t find VSYNC.
My set up is as follows:
1. Arduino generating desired sync frequency, e.g. 60hz square wave at 3.3V.
2. Signal fed to all the cameras by connecting to FSIN. No need to use VSYNC.
To test synchronisation (using old revision PCB), hook up a scope to FSIN and VSYNC:
http://i.imgur.com/NSYrI.jpg
(in sync)
Top trace is FSIN, bottom is VSYNC. VSYNC should go high (signifying the start of capture) on the rising edge of FSIN.
http://i.imgur.com/2K8YB.jpg
(out of sync)
To synchronise frames, I made a class which spawns a thread for each camera. Each thread grabs frames ASAP and places into a circular buffer and stores a timestamp (using TimeGetTime()). Then I made an algorithm to look at these timestamps and group frames together - pretty obvious stuff.
Hope someone finds it useful!