ESP8266 Community Forum

I'm interested in ESP side on how to set interrupt when data is incoming. For example I've an ESP-03, but in the pinout I can't find a dedicated pin that is an interrupt when ESP what to communicate or advise data to MCU.

All the GPIO pins can be initialized to become interrupt inputs using the functions mentioned above.

Data incoming at what side?

Data from the network (wlan) side is fully processed by the SDK code + LWIP and you will get complete packet payload through a callback function. It's all in the documentation...

Data from the UART is signalled by several interrupts that can call callback functions. The documentation about that isn't very good, for an example see my bridge: https://github.com/eriksl/esp8266-universal-io-bridge.

You cannot busy wait for characters to come. Many have stubbornly tried and many have failed