ESP8266 Community Forum

- Thu Nov 08, 2018 4:56 am #79069 the recommendation of diode is correct and best practise
and the problem comes from the 100n at rst, not internals of the ESP-12 module.

- Mon Nov 19, 2018 5:59 pm #79213 @schufti
Nope, I think it does not. The 100nF of course forms a low pass filter with any resistor in line but it won't be able to source a static current in the range of some 100µAs. A current source is the only explanation for a voltage at the RST input which is different from the calculated one based on the 10k pullup and 1k5 switched to GND by GPIO16.

@davydnorris & @schufti
Yes, fully agreed on the diode recommendation. I'll give that solution a try in the upcoming days. Connecting the anode to RST and the cathode to GPIO16 really looks best.
Indeed I've not thought about that serial reprogramming issue as my device was already in a state where I used OTA updates all the time and I was focused on getting rid of this instable deep-sleep behavior.
Until today where I bricked my OTA loop, and oops...


Best regards,
Kelrob

- Fri Mar 06, 2020 6:15 am #85974 Hi @all!
I had similar problems with ESP-12E/F module and this thread helped me a lot. In the end I had to do the following steps to make the deep sleep with my modules work:

1) RESET ---->| ----- GPIO16
connect Reset to GPIO16 via a diode (I used a 1n4007 just because I had one but I rekon most diodes will do)

2) Pull DOWN GPIO15 with 10k

3) Pull UP GPIO00, GPIO02, CH_PD/ENABLE with 10k

4) Didn't need to pull up RESET since it was already pulled up with 12k inside the modules I bought.
So check (measure) your modules, if they have already a resistor between VCC and RESET, you don't need an external one.

5) Use proper 3.3V as your VCC. I use an MCP1700-3300 LDO Voltage regulator to get 3.3V from an 18650 LiPo battery but as it provides only 250mA max, I use an 100nF ceramic parallel with an 1000uF elko to stabilize the voltage - seems sufficient.

6) For programming, use an FTDI adapter that is capable of 74880 baud. Make that your own program's serial speed, so you can see the esp's boot loader messages. Connect serial DTR with GPIO00 and serial RST with RESET for automatic reset and upload.

Enjoy!