I have a need to control the lens for a EOS camera via external software for focus stepping. to this end i have bought a dropped lens, pulled it out( it now works!) and attatched 7 wires to the lens connections.
So Far: if we number the contact pins from the raised platform 1, 2(the widest contact),3,4,5,6,7
1, no signal seen ?gnd 2 Gnd , 1ohm or less to battery gnd (longest contact in battery compartment) 3 5V supply, seems to be constant so far 4 4.8V max data, slow rising edge, bursts when half shutter button pressed. 5 5V data rising and falling edges similar , comms when menu button pressed. 6 5V clock 78KHz bursting 7 GND < 1ohm to pin2
next step is to capture comms and associate with clock, using eos control on pc for focus step then to attempt replication. Unknowns, 2 pins have comms, I2C? Uart? or SPI one way or two way comms.