ESP8266 Community Forum

- Sat Mar 19, 2016 10:39 am #43561

....RST on wemos have 10k pullup to 3.3 and 100n to GND.
I think that diodes so well protect inputs from peaks as generates double voltage.

Hi reaper7, thanks for confirming those values, I'd been too lazy to look them up and just went by the CR time-constant I was seeing on a scope. 100nF is quite a bit of charge for a cmos output to drive into. I wonder what they were thinking when they used that value on RST given that there's a frequent requirement to drive it low with GPIO16

I still think it's safest to link the two pins with around 100R. This triggers RST within well under 100uS. Here's a scope shot taken with 180R. Notice that the pulse is still at 0.5V after 300uS but the threshold is probably crossed as soon as the pulse begins.

RST.jpg

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- Sat Mar 19, 2016 1:08 pm #43570 @AdrianM - I like real tests good work!
I have only old crt oscilloscope without "hold"

I'm talking only about my experiences with wemos mini + 10u between GPIO16 and RST, this device works for me without any trouble and hangs more that one week! This is a proposal for people who have problems with different values for resistors and esp hangs.

MY GITHUB: https://github.com/reaper7/

SDM Energy Meter: https://github.com/reaper7/SDM_Energy_Meter
MLEDScroll (TM1640 led matrix): https://github.com/reaper7/MLEDScroll

- Sun Mar 20, 2016 3:58 pm #43650 Hello @reaper7 and @AdrianM , thanks for your suggestions.
My Huzzah breakout worked great for 36 hours on battery until discharge, then restarted when connected to power. No resistors, just wire between GPIO16 and RST.
Feather hangs, always, with wire and tests with various resistors (160, 330,660).

I'm really a beginner in electronics, I'm a programmer, so I understood nothing of your discussion about the capacitor between RST and GPIO16.
I've tried everything, I'll try the capacitor too... 4,7 and 10uF.

Maybe you can, from the schematics, tell the difference between the Feather and the Breakout, and understand why they behave differently. May it be a programming/library issue? After all, in the Arduino IDE you have to select a different board for compile: "Generic 8266" for the Feather and "Huzzah" for the Huzzah.

Funny thing, my project was supposed to be deployed on Huzzah, with Feather for development, because of the connectors. But then I wasted 2 weeks trying to get stable deepSleep on Feather, and Huzzah worked fine the first time.

- Mon Mar 21, 2016 2:03 am #43684 I wonder if the reason that the Feather has its own board type but Huzzah uses the generic board is because of the on-board usb-serial adaptor and it's auto-reset circuit. The IDE may have to send extra commands to the usb chip to make it perform auto-reset. With the Huzzah, you have to perform the reset for program upload yourself by pressing two buttons. WeMos D1 mini has a similar arrangement to Feather, and it too has its own board type.

Looking at the circuits connected to the RST pin in the Feather compared to the D1 mini, i can see very few differences. I can't see anything that would make wake from deep sleep unreliable on the Feather. Perhaps @reaper7 or @AdrianM could spot something.

Feather schematic
Huzzah schematic
WeMos D1 mini schematic