ESP32 Forum

Good morning,
i have a question about the urc messages scenarios :

I send a AT command :
1 - the URC can be received before the answer ?
2 - the URC can be received in the middle of the answer?
3 - the receiving is random?

I'm receving datas (for examples from a server):
+IPD:xxxxxxxx

A urc can be received in the middle? like this : +IPD,0,n:xxxxxxxxxxxxxxxxxxx+CONNECT,0xxxxxxxx or a MQTT notify

In other words , is there a "syncronization" with the ongoing trasmissions from the ESP to the microcontroller?

Thank you.

Best regards,
Lucio.

@LucioS URC messages are asynchronous and are generated by internal events (Wi-Fi, TCP/IP, MQTT, etc.).
They are not synchronized with AT command execution, so a URC may arrive before, during, or after the response of an AT command.

However, the firmware ensures that:

• Each message (AT response or URC) is output as a complete line

• Messages are not byte-interleaved

So while messages may be interleaved at the line level, they are not mixed at the character level.

So a situation like this will NOT happen: