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.
Arduino Uno
Raspberry pi 2
ESP8266-01
ESP8266-12E