Quote
uncle_bob
If you can, go for a pull down that's less than 1K ohms. It still won't pull enough to bother the regulator. The lower you go, the less likely odd events are to turn on the FET's.
The FETs are driven via a buffer (74HC125 in this case), so only a weak pull down is required between the SAM and the buffer. The regulator on the Due does not have a lot of headroom, it's worth saving mA where we can, they all add up.
I plugged in an LCD controller and the voltage dropped quite a bit. I haven't measured the overall current draw, so I wonder how close to the limit we are. We have added several bits of logic, plus stepper driver etc over RAMPS.
On the subject of E-stop, I've noticed that when activated it prevents motion on Y, Z and E0, but not X, which is a puzzle. Maybe an issue with my board, I wonder if anyone else has noticed the same thing?