It's quite simple to set up comms and send/receive data First, you need to set the PIC's registers for the data rate, based on the speed of the PIC's clock. Example below is for 38400 baud with a 3.6864MHz crystal Then perhaps wait for a request from the PC, which may be a special character like "S" (for send) or whatever you want. By handshaking with the PC, the transfer will be a little slower but may result in a more controlled transfer, particularly if the PC gets busy and can't keep up with ungoverned transmission from the PIC After a request, just put the data into the transmit buffer and off it goes Those are the basics. You can add interrupts, error routines, checksums etc etc ;================================================ ; Initialise RS232 serial comms ;================================================ ; 38k4 with BRGH = 1 @ 3.6864MHz ; 38400 = Fosc / (16 * (X+1)) ; 38400 = 3686400 / (16 * (X+1)) ; 38400 * (16 * (X+1)) = 3686400 ; 16 * (X+1) = 3686400 / 38400 ; X = ( (3686400 / 38400) / 16 ) -1 ; X = (96/16)-1 ; X = 5 bank1 movlw 0x05 ;5 = 38,400 baud movwf spbrg movlw b'00100100' ;brgh=1, Asynch, 8-bit, Tx enabled movwf txsta bank0 movlw b'10010000' ;Asynch, 8-bit, Rx enabled movwf rcsta movf rcreg,w ;clear receive buffer and rcif ;================================================ ; Wait for request from PC ;================================================ get_req bank0 movf rcreg,w ;clear receive reg, buffer, and rcif movf rcreg,w movf rcreg,w bcf rcsta,cren ;clear any errors bsf rcsta,cren btfss pir1,rcif ;wait for receive buffer to fill goto $-1 movf rcreg,w ;clear rcif ;then test received byte (in W) to see if it's a proper request ;================================================ ; Send byte to PC ;================================================ bank0 movlw databyte ;put data into transmit buffer movwf txreg ;wait here to test for byte gone bank1 btfss txsta,trmt ;byte transmission complete goto $-1 bank0 -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.