RESET and CHIP_EN pins - instability

Posts: 1
Joined: Wed Jun 24, 2015 12:22 am

RESET and CHIP_EN pins - instability

Postby lotus » Wed Jun 24, 2015 12:35 am

I've been struggling with the RESET (pin 32) and CHIP_EN (pin 7) connections on your ESP8266 (esp-03 module).

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!? Your 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?

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

Posts: 140
Joined: Mon Oct 27, 2014 10:40 am

Re: RESET and CHIP_EN pins - instability

Postby Espressif_Kelly » Wed Jul 22, 2015 8:12 pm

Hi lotus,

1.It is ok for CH-EN pin with 10kohm pull-up to VCC.

CH_EN, the power enable pin, should be powered on at the same time when or after the power supply system is powered on.

And in order to avoid unstable power when the system is just powered on, a RC time-delay circuit is recomended for CH_EN.

2.For EXT_RSTB, in order to avoid reset caused by external interference, the trace of EST_RSTB is generally required to be short, and external RC circuit is recommended and should be placed close to EXT_RSTB pin.
Besides, for relay application and so on, AC Ground and DC Ground should be separated and connected via a wire.

Any more questions, please let me know.


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