According to the reference manual on UART for PIC here(page 7), the UxSTA register have two read-only bits; TRMT and UTXBF. While writing a simple transmission program over UART, I didn't notice any change if I include
while(UxSTAbits.TMRT != 1);
before I send anything with the UxTXREG buffer. In what case is each of these bit relevant?