ESP8266 Community Forum

- Fri Jun 16, 2017 3:53 pm #67253 Thanks for that, i will get some to test with my board setup. I'm not familiar with them, i do have a bunch of 1N4001's here but i guess there must be a difference. Is there an easy explenation to why specificly a Schottky type is best to use?

Do you happen to know what specifically is being done, does the ESP requires a Voltage drop and specific current to reboot?

- Fri Jun 16, 2017 4:18 pm #67254 Generally Schottky diodes have a lower forward voltage drop compared to regular diodes. (there are exceptions to this) A 40 volt Schottky might have a forward drop of .35 volts where a regular silicon diode would be closer to .7 volts.

- Fri Jun 16, 2017 4:40 pm #67255 So in other words, the Schottky have a lower resistance than the 1N4001's?

My understanding is that GPIO16 pulls RST low OR RST pulls GPIO16 high when momentarily dropped low for reboot after sleep. (since cathode should be on GPIO16) Is this correct? Which is it?

I have tested a resistor by the way, first a 1K didn't work, but a 470Ohm works well as you suggested. I'm now working on an external trigger to wake up the WeMos board, but it's unsuccessfull. So i am kinda looking for a clue... maybe you have some idea?

Note: i've used a 50v capacitor instead, perhaps it has a higher (too high) resistance for it to work?

- Sat Jun 17, 2017 3:56 am #67265 gpio16 is strong high during deep sleep.
So if directly connected to RST you need even stronger low to reset.
This situation is bad for gpio16 and device trying to reset.
With resistor the situation is improved but not good. "The" resistor and the one from the device trying to reset (internal pin impedance) build a voltage divider and the resulting level desides about success/failure.
With diode and obligatory pull-up on rst the circuit will form sth like "wired and" ,as long as other reset sources are implemented as "open colector" (or oc-like due to diode like gpio16).