I see many CMOS sensors with the pin called trigger. WHat exactly does this pin do ? What is it used for in a camera?

My knowledge about CMOS sensors is not extensive. As far as i know the trigger I thought was used to control the accumulation time on the CMOS sensor. However, I see some articles online that talk about using this trigger pin to sync multiple cameras , something like a global shutter which discharges the CMOS sensor everytime before beginning a new read. My question, is there any way to use this trigger pin http://www.sony.net/Products/SC-HP/sensor/img/product/cmos/IMX249LQJ_LLJ_Flyer.pdf to synchronize the sensors.

  • Can you also tell us where you found this information? Can you also tell us what is your prior research on this subject and how the information you found did not answered your question? – Dragos Jan 12 '16 at 12:12
  • To the person down voting the question: Would be really nice both for the person asking the question but also for the readers to know the reason of the down vote. We are here a community and we have to learn from each other. – Dragos Jan 12 '16 at 12:14
  • It is also important to know WHICH CMOS sensor you are talking about. In case of a MT9P031 Sensor, TRIGGER is an input pin and would be used for: Snapshot trigger. Used to trigger one frame of output in snapshot modes, and to indicate the end of exposure in bulb exposure modes In case of a AR0134CS Sensor, TRIGGER, also an INPUT pin would be used for: Exposure synchronization input Each CMOS Sensor has its own specific specs, which seems to not be standard – Dragos Jan 12 '16 at 12:26
  • In that PDF you linked here, I don't find any Trigger PIN, I only find a Trigger mode. Those are 2 totally different things. – Dragos Jan 12 '16 at 12:29
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    I'm voting to close this question as off-topic because it's about electrical engineering without any real application to photography; a question isn't automatically on-topic because it's about a bit of a camera. – Philip Kendall Jan 12 '16 at 12:47

If we are talking about AR0330, as specified by you in the comments, what we find in that very PDF are following:

  • 11. If the TRIGGER or OE_BAR pins or pads are not used, then they should be tied to DGND
  • Receives slave mode VD signal for frame rate synchronization and trigger to start a GRR frame
  • (page 53) The slave mode feature of the AR0330 supports triggering the start of a frame readout from a VD signal that is supplied from an external ASIC. The slave mode signal allows for precise control of frame rate and register change updates. The VD signal is input to the trigger pin. Both the GPI_EN (R0x301A[8]) and the SLAVE_MODE (R0x30CE[4]) bits must be set to “1” to enable the slave mode.
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