init0:
clrf    TRISC,A         ;make all of PORTC an output
init1:
movlw 0x08;
movwf LATC,A; setzt Bit 3 und löscht alle anderen Bits
Mainloop:
OndelayLoop:
    decfsz  Delay1,f,A      ;Waste time.
    goto    OndelayLoop     ;The Inner loop takes 3 instructions per loop * 256 loopss = 768 instructions
    decfsz  Delay2,f,A      ;The outer loop takes an additional 3 instructions per lap * 256 loops
    goto    OndelayLoop     ;(768+3) * 256 = 197376 instructions / 250K instructions per second = 0.79 sec.
Rotate:
    bcf     STATUS,0,A        ;clear the carry
    rrcf    LATC,F,A        ;shift the LEDs and turn on the next LED to the right
    bnc     MainLoop      ;
    bra     init1        ;repeat this program forever

bsf     LATC,3,A

movlw 0x08;
movwf LATC,F,A; setzt Bit 3 und löscht alle anderen Bits

Rotate:
    bcf        STATUS,0,A        ;clear the carry
    rrcf    LATC,F,A        ;shift the LEDs and turn on the next LED to the right
    bnc   MainLoop      ;
    bsf     LATC,3,A        ;yes, it did and now start the sequence over again by turning on DS4
    bra    MainLoop        ;repeat this program forever

; PICkit 3 Starter Kit
; Assembly Lesson 3
;
; VSK @THU 17.11.2025
; MPLABX v6.20 / pic-as v3.10
; Board: PICkit 3 Low Pin Count Demo Board
; *******************************************************************
; * See Low Pin Count Demo Board User's Guide for Lesson Information*
; *******************************************************************

; config statements in Config_18F1xQ41.s
; cpu clock speed is set to 1MHz in the configuration bits
    
#include <xc.inc>

GLOBAL Delay1,Delay2;make them global -> watchable when debugging

PSECT udata_acs     ;shared memory location that is accessible from all banks
Delay1:
    DS      1       ;reserve 1 byte for Delay1
Delay2:
    DS      1       ;reserve 1 byte for Delay2

    ; -------------------LATC-----------------
    ; Bit#:  -7---6---5---4---3---2---1---0---
    ; LED:   ---------------|DS4|DS3|DS2|DS1|-
    ; ----------------------------------------

PSECT resetVec,class=CODE,reloc=2   ; define "-presetVec=0h" in custom linker options
resetVec:
;cpu clock speed is set to 1MHz in the configuration bits
    clrf    TRISC,A         ;make all of PORTC an output
    movlw   00001000B       ;start the rotation by setting DS4 ON
    movwf   LATC,A          ;write contents of the working register to the latch
MainLoop:
OndelayLoop:
    decfsz  Delay1,f,A      ;Waste time.
    goto    OndelayLoop     ;The Inner loop takes 3 instructions per loop * 256 loopss = 768 instructions
    decfsz  Delay2,f,A      ;The outer loop takes an additional 3 instructions per lap * 256 loops
    goto    OndelayLoop     ;(768+3) * 256 = 197376 instructions / 250K instructions per second = 0.79 sec.

Rotate:
    rrcf    LATC,F,A        ;shift the LEDs and turn on the next LED to the right
    btfss   STATUS,0,A      ;did the bit rotate into the carry (i.e. was DS1 just lit?)
    goto    MainLoop	    ;nope, repeat this program forever
    bsf     LATC,3,A        ;yes, it did and now start the sequence over again by turning on DS4
    bcf	    STATUS,0,A	    ;clear the carry
    goto    MainLoop        ;repeat this program forever

    END     resetVec