Just got my photon today and trying out the DAC but tinker app slider values range only from 0 to 255 when doc says should be 0 to 4095. Likewise voltage top is only .2 instead of 3.3. Appears to be a bug in the android tinker app. Is there a known fix for this app?
AFAIK the Tinker app is still treating A6 as it used to be on the Core as a PWM pin that only ranges from 0 to 255.
Maybe you could see in the Open Source section if there already is a issue opened about this for the Photon, or open one 
(Ping @ido)
There’s an update to the app in the Play store today which should fix this. If you’re still having trouble after you get the 1.4.0 update, please do speak up!
1.4.0 works fine. Thanks.