ESP8266 Community Forum

- Tue Jun 14, 2016 6:01 am #49171 Hi, this actually sounds more like very weak or missing pullup resistor to me.

Since you didn't mentioned that: What value is it?

- Tue Jun 14, 2016 1:12 pm #49191

it is more likely your power supply that needs the ferrite core, not the ESP.
The picture you present says that ESP is running well on a stable, filtered power supply.
But when presented with unhealthy influence (noise) via the power supply the ESP misbehaves.
That holds most likely true for a huge percentage of microprocessors....
Usually they proof to be susceptible to "noise" on the interrupt line, too.
To sum it up: a good clean (emc proof) design can't be beaten ...

You might be right, but I tried a couple of power supplies and with none of these the ESP interrupts worked flawless. Even via PC it did not when I used a cable w/o ferrite core.
-> Only adding a ferrite core did the trick. However, I agree that it is difficult to find a 'good', noise free powersupply.
Note: My problems are 'only' the interrupts! Other than that the ESP worked fine.

Reg. the question about pullups: I am using 10Kohm pullups.

Heiner

- Wed Jun 15, 2016 10:03 am #49220 EDIT: I am so sorry, i just posted on the wrong thread! sorry

Last edited by thehu on Fri Jun 17, 2016 5:39 pm, edited 1 time in total.

- Wed Jun 15, 2016 2:11 pm #49241

Why do i need pull ups? Everything is running on 3.3V.
I am not using any resistors.

First you need pullups on RES/CH_PD/GPIO2/GPIO0 and pulldown on GPIO15 to boot properly.
Then you could need more pullups on other GPIOs too if you are using them as input and where those inputs are driven with long wires, otherwise the wires can act as an antenna and internal pullups of ESP, if activated, won't be enough to stay HIGH level.