Mike Harrison wrote:
>
>
> a slightly smaller version...
>
>   movlw 1               ; end of byte marker
>   movwf byte_in
> loop
>  bsf clk
>  goto $+1  ; 2-cycle NOP (if needed)
>  clc
>  btfsc data_pin
>  sec
>  bcf clk         ; clear clk as soon as data has been read
>                       ; to allow maximum time for clk fall
>  rlf byte_in
>  skpc          ; loop until marker bit falls out end of byte
>  goto loop
>
> if you can arrange for data_in to be bit 0 or 7 of a port, you can
> read it into carry using rrf port,w or rlf port,w respectively.

and an even slightly smaller version

    movlw  1
    movwf  byte_in
    clrc
loop
    bsf    clk
    goto   $+1        ;probably mot necessary
    rlf    byte_in,F
    btfsc  data_pin
     bsf   byte_in,0
    bcf    clk
    skpc
     goto  loop


Scott