ESP8266 Community Forum

- Mon Sep 05, 2016 9:12 am #54529 Hi there,
In my project (based on a NodeMCU - ESP12E) I use 4 different GPIOs:
- 2 as INPUT (connected to switches) => D1 & D6 (GPIO5 & GPIO12)
- 2 as OUTPUT (connected to LEDs) => D2 & D5 (GPIO4 & GPIO14)
When the module is in DeepSleep, the LED connected to D5 (GPIO14) goes to a "dimly lit" state which is not what I expect when I want to save battery life!
I don't have the problem on GPIO4 with the other LED, it is clearly linked to GPIO14.
I saw GPIO14 was mapped to HSCLK but I thought it could be used as a simple output GPIO ...
Any suggestion???
Thanks!

- Mon Sep 05, 2016 2:47 pm #54555 Hi there,
I'm no ESP expert, so I'm not sure what to tell you to get it to turn off all the way. Have you tried changing output pins? that one may be used for something. Alternatively, if it were me, I would hook it up to an oscilloscope (if you have one) and see what the output pin is doing. it may be helpful to add a zener diode or even a normal diode or a mosfet, in order to add to your voltage drop.

- Mon Sep 05, 2016 2:56 pm #54558 Hi there,
I'm no ESP expert, so I'm not sure what to tell you to get it to turn off all the way. Have you tried changing output pins? that one may be used for something. Alternatively, if it were me, I would hook it up to an oscilloscope (if you have one) and see what the output pin is doing. it may be helpful to add a zener diode or even a normal diode or a mosfet, in order to add to your voltage drop.

- Tue Sep 06, 2016 10:40 am #54593 Yes, as I wrote above I tried GPIO4 and I don't have this behaviour.
In fact the LED I use in my case is a blue one that is quite bright when GPIO is high.
I made some measures and I have the following values when LED is on :
LED voltage : 2,6v
LED current : 0,6mA
When it goes into DeepSleep state, I can't measure the current since it is too low but it is still dimly lit.
If I just touch the anode with a metallic object, the LED does not light any more, just as if it was due to a remaining capacitor charge ...
however it I let the module into DeepSleep for many hours, the LED is still dimly lit until I unplug the USB supply cable.