ESP8266 Community Forum

Posted: **Tue May 31, 2016 10:54 pm**

martinayotte wrote:What firmware are you using on ESP ?
If it is AT firmware, beware that every commands requires both CR+LF, not only CR.

As I said its only rx problem. I am flashing firmware compiled by arduino. Works for ESP-01 (1k/1.8k voltage divider) but not for ESP-12E (10k/22k divider).
Another question: What if RX pin input goes above Vcc. For me, Vcc = 3.2v, Rx input High = 3.4v.

Posted: **Wed Jun 01, 2016 6:24 am**

Subhajit Das wrote:Another question: What if RX pin input goes above Vcc. For me, Vcc = 3.2v, Rx input High = 3.4v.

VCC+0.3V should not pose a problem (datasheet only specifies 3.6V max. without mentioning VCC).
If on doubt, you can use a mosfet as level shifter or clamp the input voltage with a zener diode.

Posted: **Thu Jun 02, 2016 7:06 am**

I confirm that RX works for 1k/1.8k combination. But it heats like hell.
I checked input impedance (using multimeter, not actual i guess). It is 450E. What? Just 450? Isn't it supposed to be 1M or something for a MOSFET?

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