Add dumps for Sony E-mount lens protocol

lens_mounts/sony_emount/README

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+-------------------------------------------------------------------------------
+Sony E-mount camera/lens
+-------------------------------------------------------------------------------
+
+These are dumps from a Sony E-mount camera/lens.
+
+Details:
+https://en.wikipedia.org/wiki/Sony_E-mount
+
+These were taken using a modified 16mm Meike extension tube that brings out
+each lens contact to a 10-pin ribbon cable.
+
+Pinout of the mount is as follows (these pins are from left to right
+looking at a lens from the rear):
+
+1: LENS_GND - Lens motor GND
+
+2: LENS_POWER - Lens motor power
+   Can be either 5.0V or unregulated Vbat (7.4V nominal) - This is somehow
+   negotiated between body and lens.
+
+3: LOGIC_GND - Ground for lens logic circuitry
+
+4: BODY_VD_LENS - As-of-yet unknown body->lens signalling
+   In nearly all cases, it is normally high but pulses low at a very low duty
+   cycle at 60 Hz (is it 50 in EU?).
+
+5: LOGIC_VCC - Lens logic power
+   3.15V. All data lines described below are 3.15V logic high.
+
+6: LENS_CS_BODY - Handshaking line from lens to body
+   Always high when RXD is transferring data, normally low.
+
+7: RXD - Serial data from lens to body
+   Starts at 750 kbaud, usually negotiates up to 1.5 Mbaud during init.
+   8N1, LSB-first.
+
+8: TXD - Serial data from body to lens
+   Same speeds as above.
+
+9: BODY_CS_LENS - Handshaking line from body to lens
+   Always high when TXD is transferring data.
+
+10: LENS_XDETECT - (weakly) pulled high by the body
+    Grounded to LOGIC_GND by the lens, or sometimes via 680 Ohm resistor
+    (Viltrox EF-NEX II). Used to detect presence of a lens. Body will not
+    output power unless this is grounded.
+
+
+Logic analyzer setup
+--------------------
+
+The logic analyzer used was an fx2lafw board (at 6MHz):
+
+http://www.amazon.com/gp/product/B00ZOC23TK
+
+  Probe       Lens mount
+  ----------------------
+  0           BODY_VD_LENS
+  1           VCC
+  2           LENS_CS_BODY
+  3           RXD
+  4           TXD
+  5           BODY_CS_LENS
+
+
+Data
+----
+
+Protocol (quick summary):
+
+Data is only transmitted when a CS line goes high. Only one frame of data is
+transmitted per high CS period. All frames start with 0xF0, followed by a
+command ID byte. All frames end with 0x55, this is preceded by a 16-bit
+checksum of the command ID byte plus all payload bytes. Checksum is least
+significant byte first. Frames from body to lens are sometimes padded with
+additional 0x00 bytes beyond 0x55.
+
+A CS line can go high without any data being transmitted. This has so far
+only been seen during a speed change.
+
+The protocol appears to assume fixed frame lengths for a given command ID.
+Occurrences of 0x55 within a frame are NOT escaped.
+
+During "idle" operation, a low pulse of BODY_VD_LENS appears to trigger two
+status response frames from the lens to the body, followed by two frames from
+body to lens.
+
+Summary of hardware used:
+
+ - Body: Sony ILCE-A6000
+ - Probe breakout: Meike 16mm macro extension tube with all pins wired out
+   to a ribbon cable
+ - Lenses:
+   - Sony SEL55210 55-210mm zoom lens, initialization captured at both 55mm
+     and 210mm zoom settings
+   - Viltrox EF-NEX II adapter - Canon EF to Sony E mount electronic adapter
+   - Canon EF 50mm/1.8 STM - Used with Viltrox adapter
+   - Canon EF-S 24mm/2.8 STM - Used with Viltrox adapter
+   - Sony SELP1650 16-50mm Power Zoom lens - Initialization only captured at
+     the lens' default power-on focal length due to PZ + retractable lens
+
+More details can be found in the dpreview thread at:
+http://www.dpreview.com/forums/post/56133485
+