Bit-banging: is it the 'only' way?

[Demon]

A little more on p. 101:

Parity is not supported by the hardware, but can be implemented in software (and stored as the ninth data bit).

In order to select 9-bit transmission, transmit bit TX9 (TXSTA<6>) should be set and the ninth bit should be written to TX9D (TXSTA<0>). The ninth bit must be written before writing the 8-bit data to the TXREG register. This is because a data write to the TXREG register can result in an immediate transfer of the data to the TSR register (if the TSR is empty). In such a case, an incorrect ninth data bit may be loaded in the TSR register.

So it seems as if you can use the 9th bit for your use, unless I missed something.

[Archangel]

This is from the 14 bit core library . . .

;****************************************************************
;* Default hardware serial port values                          *
;****************************************************************

    ifndef HSER_BITS
HSER_BITS = 8            ; Default to 8 bits
    endif
    ifndef HSER_RCSTA           ; Receive register data
      if (HSER_BITS != 9)
HSER_RCSTA EQU 90h              ; Receiver enabled
      else
HSER_RCSTA EQU 0d0h             ; Receiver enabled for 9 bits
      endif
    endif
    ifndef HSER_TXSTA           ; Transmit register data
      if (HSER_BITS != 9)
HSER_TXSTA EQU 20h              ; Transmitter enabled
      else
HSER_TXSTA EQU 60h              ; Transmitter enabled for 9 bits
      endif
    endif
    ifndef HSER_BAUD            ; Baud rate
HSER_BAUD EQU 2400
    endif
    ifndef HSER_SPBRG           ; Baud rate generator register data
      if (OSC == 3)
    if (((HSER_TXSTA) & 04h) == 0)
HSER_SPBRG = (((3579545 / (HSER_BAUD)) + 32) / 64) - 1    ; For BRGH = 0
    else
HSER_SPBRG = (((3579545 / (HSER_BAUD)) + 8) / 16) - 1    ; For BRGH = 1
    endif
      else
    if (((HSER_TXSTA) & 04h) == 0)
HSER_SPBRG = ((((1000000 * (OSC)) / (HSER_BAUD)) + 32) / 64) - 1    ; For BRGH = 0
    else
HSER_SPBRG = ((((1000000 * (OSC)) / (HSER_BAUD)) + 8) / 16) - 1    ; For BRGH = 1
    endif
      endif
    endif
    ifdef HSER_EVEN
HSERPARITY_USED = 1             ; Parity used if even
    endif
    ifdef HSER_ODD
HSERPARITY_USED = 1             ; Parity used if odd
    endif

;****************************************************************

You might modify to achieve what you want, save an unaltered copy or make up an include file.

[kellyseye]

Sorry for the lengthy delay in replying.

I've downloaded the 16F877 datasheet and obtained a couple of units for experimentation - this seems to be the ideal solution and I thank you all for your imput.

best wishes