Sony E mount reverse engineer

Sony E mount reverse engineer

This page contains data collected from public postings

http://www.dyxum.com/dforum/emount-electronic-protocol-reverse-engineering_topic119522.html

http://www.dpreview.com/forums/post/56133485 http://www.dpreview.com/forums/post/56587712 http://www.dpreviewer.net/forums/thread/3968755?page=2

E-mount protocol is UART-based, little Endian. https://github.com/Entropy512/sigrok-dumps/blob/fdc2bdec17a44f2ef45a6a5e1f6664093dd4adec/lens_mounts/sony_emount/README 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, 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. Lens ID [[1]] The main focus position calculations (Packet 0x30 bytes 7/8 and bytes 25/26) appear to be reasonably correct/consistent with all native E-mount lenses I've looked at. These two values are always VERY close to each other and I don't know why there are two fields with almost the exact same data, but Techart seems to have gotten this one right. They are influenced by focal length but not in a linear fashion. They increase as the lens focuses closer (lens element moves away from sensor). However, there's a third focus position field at bytes 31/32 The value of this field is approximately 110*sqrt(focal length) at infinity focus! SONY'S SERVICE MANUAL: [[2]]