I saw your design on G+ and commented there (Re: good choice on connectors), but just thought of something else to ask.
Do you have any thermistor input protection (over-voltage)?
I don't know how many people have fried the analog inputs of their electronics due to accidentally shorting the hot end +Volts to the thermistor input, but it's a lot.
If you haven't, take a look at RAMBo and also at RAMPS-FD for methods using a set voltage source and a few diodes to crowbar limit the voltage. On RAMPS-FD (which is 3.3V) we use a shunt reg as zeners just aren't tolerant enough for voltages below about 4.5V (the breakdown voltage elbow gets more curved).
Do you have any thermistor input protection (over-voltage)?
I don't know how many people have fried the analog inputs of their electronics due to accidentally shorting the hot end +Volts to the thermistor input, but it's a lot.
If you haven't, take a look at RAMBo and also at RAMPS-FD for methods using a set voltage source and a few diodes to crowbar limit the voltage. On RAMPS-FD (which is 3.3V) we use a shunt reg as zeners just aren't tolerant enough for voltages below about 4.5V (the breakdown voltage elbow gets more curved).