ESP8266 Community Forum

- Fri Jul 13, 2018 1:38 pm #77028 Since this thread is discussing the differences between the ESP-12S and older modules, I want to bring up an issue I came across. I'm using these modules in Deep Sleep and it wakes up every 30s automatically (tying GPIO16 and RST to get auto-wakeup). I noticed sometimes that the ESP-12S "hangs" when coming out of wakeup. I did some investigating and noticed that the wakeup pulse is really crappy on the ESP-12S but pristine on the ESP-12E module. Has anyone seen this?

ESP-12S




ESP-12E



I also confirmed it on two NodeMCU boards with each module


I started another post showing the test code I'm using a couple days ago, viewtopic.php?f=6&t=17975

- Fri Jul 13, 2018 5:33 pm #77034 Could you add some bypass capacitors across VCC and GND? The ESP-12S has more internal capacitance than the previous models but I am concerned that your setup might be causing the issues you are seeing. You are not comparing apples to apples. A NODEMCU board with a proper power source compared to what you show in the top two pictures.

Use the shortest lead length you can. Try something like 100uF-470uF.

- Fri Jul 13, 2018 6:08 pm #77035 There are actually two separate test setups shown here:

Standalone module test; one using the ESP-12S and one using the ESP-12E with the required external resistors.

NodeMCU test; one using the ESP-12S and one using the ESP-12E.

In both cases the ESP-12S pulse is crappy and the ESP-12E pulse is perfect. If it were a bypass capacitor issue, you would assume that the ESP-12E pulse would be the bad one because the ESP-12S is supposed to have more internal capacitors on the power lines.

- Fri Jul 13, 2018 8:27 pm #77036

There are actually two separate test setups shown ...

If it were a bypass capacitor issue, you would assume that the ESP-12E pulse would be the bad one because the ESP-12S is supposed to have more internal capacitors on the power lines.

Good to know. I should have looked more carefully at the modules. I was pretty sleepy at the time. (have since had a nap)