ESP8266 Community Forum

- Tue May 03, 2016 10:33 am #46783

All three of my ESP-01 that I bought on eBay work fine without the resistors.

That kind of answers is the syndrome "it is working for me" ...

Such syndrome is simply NOT a "good practice" !

If your environment change, such getting more EMI around, it will simply stop working ...

I'm saying that since more than a year : "PullUps/PullDown on those special pins are mandatory !"

- Tue May 03, 2016 2:13 pm #46806

All three of my ESP-01 that I bought on eBay work fine without the resistors.

That kind of answers is the syndrome "it is working for me" ...

Such syndrome is simply NOT a "good practice" !

If your environment change, such getting more EMI around, it will simply stop working ...

I'm saying that since more than a year : "PullUps/PullDown on those special pins are mandatory !"

They are IO pins.

- Tue May 03, 2016 2:26 pm #46809 I think you've misundertsood :
GPIO15/GPIO2/GPIO0/CH_PD/RES are special pins that act as input to determine which boot mode is selected at reset or powerup or wakeup from deepSleep().
If the are strong EMI around, leaving those pins in an unknown floating states, you won't be sure in which mode the ESP will boot up. And if it is located in an inaccessible location, you won't be able to restart it, it will stay hanged forever until you do maintenance locally.
For other GPIOs, we don't care of leaving them floating, since they are not influencing the boot process.