Mario Thomaidis wrote:

> Once a new value is loaded into the TXREG, it is transferred to the
> TSR register one instruction later (provided of course the last value
> in the TSR has been completely sent - otherwise, it sits there until
> TSR is empty).

  Sorry, I passed over the original code.  You *must not* clear TXREG
after each byte sent.  Clearing it is actually instructing that a NUL
character be sent, and you'll never know half the time whether what is
sent is the NUL or the other character you loaded later.

> You do not need to disable the transmitter in between bytes (for
> normal operation

  Again, you *must not* do this, you are most likely to abort part of
the current character.  Whether you produce glitches by doing so depends
on the setting of the port registers.  But doing so immediately after
sending a NUL really is asking for trouble!

  This is actually less of a problem if you are using TRMT instead of
TXIF which is what you should really be using.  Using TRMT avoids the
"first character sent" problem and slows transmission by adding "extra
stop bits" which is not necessarily a Bad Thing.

  So, remove the instruction to send the NUL, and make sure that
enabling the transmitter is part of your initialization code, not stuck
within the character sending code.

  Mario's code is OK except that you may strike the "first character"
problem.  It may be better to use:

UART_TRANS
        BSF     STATUS, RP0     ; Bank 0 (PIR1 & TXREG)
        MOVWF   TXREG           ; Transmit value loaded into W prior
LOOP    call    TRANS_DELAY
        BTFSS   PIR1, TXIF      ; TXIF=1 ? (= TXREG clear)
        GOTO    LOOP            ;
        RETURN
--
  Cheers,
        Paul B.