Hello Sathish
After doing a bit of research, I have found that the TC while timer is a hardwired internal mechanism of STP and cannot be observed directly. It can be configured indirectly by adjusting the hello timer, since the TC while timer is 2x the hello timer.
You can also see if the TC while timer is currently non-zero by examining if the TC flag is set (as seen in the output of the show spanning-tree detail command).
Other than that, there is no way that I know of to directly observe the TC while timer.
I hope this has been helpful!
Laz