onsdag den 3. februar 2016

Analyzing Sony's Multiport - Part 2

Hello there!

 It is time for a little update accoring the functionalities of Sony's Multiport interface with Sony's A6000 photo camera.

 To sumarize the last post:

 - Pinout of the Sony Multiport at the newer camera models (since 2014 as far as I know) is:

1: "VBUS" - 5V- Supply USB-Host
2: "D-" - USB-data (negative)
3: "D+" - USB-data (positiv)
4: "USB_ID" - for USB-OnTheGo (unknown if support/used by camera)
5: "GND" - in camer aconnected with Pin 14 ("AV_GND")

6: "D_3.1V" / "LANC_DC" - output supply for 3.1 to 3.3V (possible load unknown, better do not use)
7: "XRESET_REQ" - input for Reset-Request (untested)
8: "UART_TX" / "LANC_SIG" - optional output for serial data (Debug) or LANC (depends on pin 10 coding; serial interface assumed as 9600 baud, 8N1)
9: "UART_RX" / "BOOT_IN" - optional input for serial data (Debug) and Bootloader (depends on pin 10 coding; serial interface assumed as 9600 baud, 8N1; bootloader function not verified)
10: "AD_JACK_IN"/"Select" - analog input for resistance recognition to determine functionality of connected accessory (remote, programmer?, ...)
11: "LINEOUT_R" / "XAE_LOCK_SW" - optional audio out (right, assumed decoupled via camera internal capacitor) and/or input for trigger button (half press) in photo mode of camera (depending on resistance at pin 10 "AD_JACK_IN")
12: "LINEOUT_L" / "XSHUT_SW" - optional audio out (left, assumed decoupled via camera internal capacitor) and/or input for trigger button (full press) in photo mode of camera (depending on resistance at pin 10 "AD_JACK_IN")
13: "VIDEO" - optional composite-video-output (no signal at A6000 camera; video out only via HDMI at this model)
14: "AV_GND" - internally connected to Pin 5 ("GND"; USB-pins)
15: "XPWR_ON" - input for external ON/OFF-function (short to camera GND for triggering on/off)


Functionalities of this list that are working at Sony A6000 (and most probably at Sony A5100 and Sony A5000) are:


1. Trigger autofocus function via shorting pin 11 to ground (="half press"; works both in photo mode and while recording video)

2. Trigger photo via (= full press):
   a. FIRST triggering AF function (shorting pin 11 to ground)
   b. Shorting pin 12 to ground directly afterwards or better while shorting pin 11 to ground 
       (my camera is NOT taking a photo when only pin 12 is shorted to ground!)

3. Switching camera on/off via shorting pin 15 to ground (only when the main power switch at photo button is priorly set to 'on')

4. Camera is responding on serial port (pin 8) when connecting pin 10 via a 'x' kOhm resistor to ground (for A6000, response has been seen with value of 100kOhm). 

None of these functionalities have anything to do with the Sony Multiport protocol I'm still trying to analyze. I'm very sorry I haven't any better news until now. 

One additional word to functionality number 3:
With A6000 (and presumably A5100/A5000) this functionality does only work when the camera is switched to 'on' via its main power switch at the photo button. I don't have a dummy for the battery compartment, so I can't test how much power the camera is consuming when main power is on and camera switched of via pin 15. And I bet there is some minor power consumption when shutted off via pin 15 'soft off'. 
Why do i bet? because the camera can be woken up again via the same pin. In contrary to when the camera is shut off via the 'main power switch'. So finally lets say the camera is going into some kind of power saving mode. 
I don't have a  RX100MK2 (or any later RX100 model from Sony), but as far as I know, the RX100 (since MK2) should be completly power controllable via the pin 15 function. Why? because these cameras have a power button, not a mechanical power switch. But this is unverified, at least by myself. 

Any new findings according the Multiport protocol itself?

Yes, at least a bit:
When the video recording is strated and/or stopped via the recording button at the right back side of the camera, there is some kind of status message sent via the serial pins (find out which!).

The according bus messages are as in the following pictures from my scope:






The first picture shows the overview of the two data bursts sent by the camera. The following two pictures show the first data burst in more detail and the second in more detail.
I don't know what this means yet, but I guess these are some status messages for a connected remote control. Persumably to keep camera and remote in sync.
Sadly there are no such messages when you push the photo trigger button (half & full press) or when you operate the zoom.
I will try to check if there are messages sent out when the camera is operate via the AF pin, photo trigger pin and on/off pin, but for this I will have to modify my connector again and add some more wires.

So long for today. I will keep you all posted when I have some more findings about the protocol itself. 
At least there is the easy possibility (i.e. via teensy, or any 3.3V Arduino style board)  to shoot some photos (with proir AF trigger), use AF when recording videos and to set the camera to "power safe" when you need it.

All the best!

p.s.:
I am still interested in exchanging findings or trying some serial message suggestions if someone is keen to support. :)

I also got my DYS 3 axis NEX gimbal delivered lately. Will try to post a small build log soon, because there are a lot of parts to join with this construction kit.