PIC16F684 Part 011 - Controlling a 74HC595 Shift Register, Carry Bit?

PIC16F684 Part 011 - Controlling a 74HC595 Shift Register, Carry Bit?
Watch my 74HC595 Shift Register (Serial in Parallel Out) video: • 74HC595 Shift Register...
See the 74HC595 datasheet: www.ti.com/lit/ds/symlink/sn7...
PIC16F684 datasheet: ww1.microchip.com/downloads/e...

[@2bit661]

;free sample code, copy and paste
processor 16F684
include "p16f684.inc"
; Configuration settings
__CONFIG _INTRC_OSC_NOCLKOUT & _WDT_OFF & _MCLRE_OFF

R1 EQU 0x20 ; outer loop counter
R2 EQU 0x21 ; inner loop counter
C1 EQU 0X22 ; specify file to experiment with
; Define connections
#define SER_IN PORTA, 0 ; RA0 connected to 74HC595 SER_IN
#define L_Clock PORTA, 1 ; RA1 connected to 74HC595 L_Clock
#define Clock PORTA, 2 ; RA2 connected to 74HC595 Clock

; Main program start
org 0x0000
goto Initialize
; Main program
Initialize:
; Initialize ports
bsf STATUS, RP0 ; Switch to Bank 1
clrf ANSEL ; Set all pins to digital
clrf TRISA ; Set all pins of PORTA as output
bcf STATUS, RP0 ; Switch to Bank 0

CLRF C1

LOOP

BITTESTER
BTFSC C1, 0
BSF SER_IN ; PORTA, 0 (RA0) controls the serial input on the shift register
CALL DELAY
CALL SHIFT_CODE

BTFSC C1, 1
BSF SER_IN
CALL DELAY
CALL SHIFT_CODE

BTFSC C1, 2
BSF SER_IN
CALL DELAY
CALL SHIFT_CODE
BTFSC C1, 3
BSF SER_IN
CALL DELAY
CALL SHIFT_CODE

BTFSC C1, 4
BSF SER_IN
CALL DELAY
CALL SHIFT_CODE

BTFSC C1, 5
BSF SER_IN
CALL DELAY
CALL SHIFT_CODE

BTFSC C1, 6
BSF SER_IN
CALL DELAY
CALL SHIFT_CODE

BTFSC C1, 7
BSF SER_IN
CALL DELAY
CALL SHIFT_CODE

BSF L_Clock ; L_CLOCK (PORTA, 1) sets or latches previously-sent 8 bits
CALL DELAY
BCF L_Clock ; L_CLOCK cleared back to low
CALL DELAY

RRF C1, F ; rotate right f through carry

GOTO LOOP

SHIFT_CODE ; shift register subroutine
BSF Clock ; Clock pin (PORTA, 2), clocks in whatever serial input (PORTA, 0) is doing
CALL DELAY
BCF Clock
CALL DELAY
BCF SER_IN
CALL DELAY
RETLW 0

DELAY MOVLW 0x80 ; adjusted delay time
MOVWF R1
AGAIN MOVLW 0x20
MOVWF R2
HERE NOP
NOP
DECFSZ R2, F
GOTO HERE
DECFSZ R1, F
GOTO AGAIN
RETLW 0

END ; Needed to end the program.