Serial data stream to Nextion

Hi, I want to make t0.(Text) visible for “no data” information when there is no serial data stream to Nextion. can you help me?

How are you getting the data stream. Simplest way would be to send that text to t0 from whatever is creating the data stream.

I get the data stream as a four digit number like “0000” and 4800 baud from microcolttroller. I want “----” to be visible in the to.text 3 seconds after the data stream is interrupted.

Does the microcontroller know when the data stream is interrupted?

Yes, the Microcontroller knows when the data stream is interrupted. When the data flow is interrupted, the microcontroller enters a vicious circle.
I think the Microcontroller should send a command like “tm0.en=1” to the screen only once when the data flow is interrupted. On the other hand, when the timer is 3 seconds, I have to change the text box text with a command like “t4.txt=”----" or make the t4 text box visible. I set up the logic this way, but I couldn’t design which lines to write where.