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RESET and CHIP_EN pins - instability

PostPosted: Tue Jun 23, 2015 11:41 am
by Lotus
Hi,
I've been struggling with the RESET (pin 32) and CHIP_EN (pin 7) connections on the ESP8266 (esp-03 module).

CHIP_EN:
I initially tried a 10 kohm pull up to Vcc on this pin and it causes random resets, sometimes into an unknown state where I see >500mA current drawn on Vcc with the IC getting very hot. I have subsequently connected the CHIP_EN pin directly to Vcc to fix this issue. What are the specs for this pin!? The latest user guide shows a 5.1 kohm pullup and 10 kohm pulldown presumably for enable and disable respectively? Or can I directly connect this pin to Vcc and GND?

RESET:
I notice this pin is extremely sensitive to noise pickup causing device resets. I have tried an external 1 kohm pull up with a 100 nF caps with no real luck. I notice the user guide has an external 5.1 kohm pull up and 100 pF cap, maybe this will filter noise better?

Re: RESET and CHIP_EN pins - instability

PostPosted: Tue Jun 23, 2015 8:41 pm
by tytower
Just as an aid perhaps, I connect both pins to high direct . Have not bothered to implement any resistors yet . That said I think their purpose is to stop big shorts from happening as appears to be the case with yours ? 500mA ! Wow .

If the chip is still alive what other connections do you have?

Re: RESET and CHIP_EN pins - instability

PostPosted: Tue Jun 23, 2015 9:08 pm
by martinayotte
Just as an aid perhaps, I connect both pins to high direct . Have not bothered to implement any resistors yet .

That is not a good practice on "undetermined I/O state", it is only good and it is "known Input Only".

Re: RESET and CHIP_EN pins - instability

PostPosted: Wed Jun 24, 2015 12:28 pm
by kolban
Lotus,
I don't have any thoughts or guidance to provide but your post resonates with me. I have found that my ESP8266s get "boiling hot" very quickly and yet check after check after check seems to show that I have wired them correctly. I figured I had "fried" them and have ordered a bunch more for testing so that I can get "scientific" on my tests and make notes to the point where the heat starts getting generated. But to the best of my knowledge, I can't see any explicit shorts and yet apply a 3.3V to the device causes it to heat to "burn to the touch" temperature. I can recreate this at will.

It relieves me to think that there might be others out there who are experiencing the same.