Bits 15:8 GT[7:0]: Guard time valueThis bit-field is used to program the Guard time value in terms of number of baud clockperiods.This is used in Smartcard mode. The Transmission Complete flag is set after this guard timevalue.This bit field can only be written when the USART is disabled (UE=0).Note: If Smartcard mode is not supported, this bit is reserved and forced by hardware to ‘0’.Please refer to Section 29.4: USART implementation on page 887.