Adjusting the Tx Rx switching

Hi everyone,

I want to adjust the switching time of Tx and Rx and FLEX 1800
daughterboard. USRP just checks the FPGA FIFO if it is full or empty
then decides to transmit or receive. But i couldn’t find anything
about how to adjust the Tx and Rx switching time. I mean is it
possible to transmit for a determined amount of time and then receive
for a determined amount of time.