Actually, it does not work correctly. It give good readings up to 6 meters then become unresponsive, but the lidar pulsewidth is correct. I also do not see a difference in the voltage level of the waveform, when the Pixhawk is working or not. This appears to be a code issue. Also, when the Pixhawk does appear to see the pulse, the code does not enact avoidance if I move an obstacle under the vehicle when it is hovering.
If you want to try PWM just connect Lidar mode control to Pixhawk pin#55. Put a roughly 680 uf cap across the lidar power and gnd leads. Set up the configuration parameters as instructed for lidarlite v2.
Tomorrow, I'll upgrade to APM v3.5, then, try the I2C connection with RNGFND_TYPE=3. I see claims that works in other forums..