Stop/continue While loop block

[Moris526]

Hi.

I have this situation


I have a While loop reading serial and polling data from a board

While True:

    if (ser.inWaiting() > 0):
          data=ser.readline()
          
    trellis.sync()
   
    time.sleep(0.02)

What I want to do, if possible, is :

When data is coming from serial, then stop reading the board (trellis.syc) , and then with some marker from serial start reading the board again.

Any help?