Hi all,

While reading the piclist on the topic about rs233,
an idea came to me for sending fast asynchronous data.
A similar routine may have been discovered and posted
before. But just in case, I will share this to all.
This routine is not yet tested and may contain bugs.

SEROUT:
      RRF    DATA,W        ;reformat data to have:
      XORWF  DATA          ;  1 = bit change
                           ;  0 = no bit change
                           ;
      MOVLW  (1<<S_PIN)    ;W = serial pin mask
      BCF    S_PORT,S_PIN  ;start bit
      SKPNC                ;bit 0
       XORWF S_PORT        ;
      BTFSC  S_PORT,0      ;bit 1
       XORWF S_PORT        ;
      BTFSC  S_PORT,1      ;bit 2
       XORWF S_PORT        ;
      BTFSC  S_PORT,2      ;bit 3
       XORWF S_PORT        ;
      BTFSC  S_PORT,3      ;bit 4
       XORWF S_PORT        ;
      BTFSC  S_PORT,4      ;bit 5
       XORWF S_PORT        ;
      BTFSC  S_PORT,5      ;bit 6
       XORWF S_PORT        ;
      BTFSC  S_PORT,6      ;bit 7
       XORWF S_PORT        ;
      NOP                  ;delay
      BSF    S_PORT,S_PIN  ;stop bit = 1
      RETURN

This gives only 2 cycle per bit which is quite fast.
On a 4MHz pic, it can send max. 500KBps.

Reggie