Home » Archimedes archive » Acorn User » AU 1997-10 A.adf » Regulars » RTR/Examples/Timer
RTR/Examples/Timer
This website contains an archive of files for the Acorn Electron, BBC Micro, Acorn Archimedes, Commodore 16 and Commodore 64 computers, which Dominic Ford has rescued from his private collection of floppy disks and cassettes.
Some of these files were originally commercial releases in the 1980s and 1990s, but they are now widely available online. I assume that copyright over them is no longer being asserted. If you own the copyright and would like files to be removed, please contact me.
| Tape/disk: | Home » Archimedes archive » Acorn User » AU 1997-10 A.adf » Regulars |
| Filename: | RTR/Examples/Timer |
| Read OK: | ✔ |
| File size: | 0D84 bytes |
| Load address: | 0000 |
| Exec address: | 0000 |
File contents
; TIMER MODULE FOR PROCESSING DATA WITH AN
; ACCURATE CLOCK. ONE MILLISECOND AND 100
; MILLISECOND TIMING REFERENCES ARE GENERATED
; FROM THE PIC CLOCK RUNNING WITH A 4 MHz CRYSTAL.
; TO RUN FROM AN EXTERNAL 1 MHz STANDARD SET UP
; THE PIC TO RUN FROM AN EXTERNAL CLOCK AND REMOVE
; THE PRESCALER OPTION.
; PIN 8 - 5 uS PULSE AT A PRF OF 1 KHz
; PIN 10 - 5 Hz SQUARE WAVE
; By Bill Jeffs
;=============================
;
; DEFINITIONS
;
;-------MICROPROCESSOR--------
;
LIST P=16C84
;
;-------GENERIC---------------
;
W EQU 0
F EQU 1
;
;-------REGISTERS-------------
;
RTCC EQU H'01' ; REGISTERS DEFINED USING
STATUS EQU H'03' ; HEX NOTATION
PORTB EQU H'06'
INTCON EQU H'0B'
WSAVE EQU H'0C'
SSAVE EQU H'0D'
OPTREG EQU H'01' ; ACTUAL ADDRESS H'81' SO SET TO PAGE 1
TRISB EQU H'06' ; ACTUAL ADDRESS H'86' SO SET TO PAGE 1
DSEC EQU H'0E' ; DECISEC COUNTER
;
;-------STATUS BITS-----------
;
C EQU 0
Z EQU 2
TOIF EQU 2
RP0 EQU 5
TOIE EQU 5
GEI EQU 7
;
;-------START-----------------
;
ORG H'00' ; START VECTOR
GOTO MAIN
;
ORG H'04' ; INTERRUPT VECTOR
GOTO INTRPT
;
;-------SUBROUTINES-----------
;
ORG H'06'
;
;-------INITIALISE------------
;
INIT MOVLW 0
MOVWF PORTB ; CLEAR PORT B FOR CLEAN START
MOVLW B'00000001' ; SET PRESCALER TO DIV BY 4
BSF STATUS,RP0 ; SET FOR REGISTER PAGE 1
MOVWF OPTREG ; OPTREG IS IN PAGE 1
MOVLW 0 ; SET PORTB TO OUTPUT
MOVWF TRISB ; TRISB IS IN PAGE 1
BCF STATUS,RP0 ; RETURN TO PAGE 0
MOVLW 100
MOVWF DSEC ; LOAD DECISEC COUNTER
BSF INTCON,TOIE ; TIMER INTERRUPT ENABLE
BSF INTCON,GEI ; GLOBAL INTERRUPT ENABLE
RETURN
;
;-------SERVICE INTERRUPT-----
;
INTRPT MOVWF WSAVE ; SAVE W REGISTER
SWAPF STATUS,W ; STATUS WILL NOT BE CHANGED
MOVWF SSAVE ; SAVE STATUS REGISTER
BCF INTCON,TOIF ; CLEAR INTERRUPT FLAG
;
MOVLW H'04' ; LOAD MASK TO TOGGLE BIT 2
XORWF PORTB,F ; AND TOGGLE IT
NOP ; AND DELAY FOR 5 CLOCK CYCLES
NOP
NOP
NOP
XORWF PORTB,F ; AND RETURN FOR 5 CYCLE PULSE
MOVLW 5 ; 256-(250-14)=COUNT UP FROM 20/4
MOVWF RTCC ; RELOAD RTCC
DECF DSEC,F ; DECREMENT COUNTER
BTFSC STATUS,Z ; SKIP IF NOT ZERO
CALL TOGGLE ; RESET COUNTER AND TOGGLE OUTPUT
;
SWAPF SSAVE,W ; RESTORE STATUS WITHOUT
MOVWF STATUS ; CHANGING ANY STATUS BITS
SWAPF WSAVE,F ; RESTORE W REGISTER WITHOUT
SWAPF WSAVE,W ; CHANGING ANY STATUS BITS
RETFIE ; AND THEN RETURN FROM INTERRUPT
;
;-------PROCESS DECISECOND---
;
TOGGLE MOVLW H'64'
MOVWF DSEC
MOVLW H'10'
XORWF PORTB,F
RETURN
;
;-------PROGRAM STARTS HERE---
;
MAIN CALL INIT
LOOP NOP
GOTO LOOP
END
00000000 3b 20 54 49 4d 45 52 20 4d 4f 44 55 4c 45 20 46 |; TIMER MODULE F| 00000010 4f 52 20 50 52 4f 43 45 53 53 49 4e 47 20 44 41 |OR PROCESSING DA| 00000020 54 41 20 57 49 54 48 20 41 4e 0a 3b 20 41 43 43 |TA WITH AN.; ACC| 00000030 55 52 41 54 45 20 43 4c 4f 43 4b 2e 20 4f 4e 45 |URATE CLOCK. ONE| 00000040 20 4d 49 4c 4c 49 53 45 43 4f 4e 44 20 41 4e 44 | MILLISECOND AND| 00000050 20 31 30 30 0a 3b 20 4d 49 4c 4c 49 53 45 43 4f | 100.; MILLISECO| 00000060 4e 44 20 54 49 4d 49 4e 47 20 52 45 46 45 52 45 |ND TIMING REFERE| 00000070 4e 43 45 53 20 41 52 45 20 47 45 4e 45 52 41 54 |NCES ARE GENERAT| 00000080 45 44 0a 3b 20 46 52 4f 4d 20 54 48 45 20 50 49 |ED.; FROM THE PI| 00000090 43 20 43 4c 4f 43 4b 20 52 55 4e 4e 49 4e 47 20 |C CLOCK RUNNING | 000000a0 57 49 54 48 20 41 20 34 20 4d 48 7a 20 43 52 59 |WITH A 4 MHz CRY| 000000b0 53 54 41 4c 2e 0a 3b 20 54 4f 20 52 55 4e 20 46 |STAL..; TO RUN F| 000000c0 52 4f 4d 20 41 4e 20 45 58 54 45 52 4e 41 4c 20 |ROM AN EXTERNAL | 000000d0 31 20 4d 48 7a 20 53 54 41 4e 44 41 52 44 20 53 |1 MHz STANDARD S| 000000e0 45 54 20 55 50 0a 3b 20 54 48 45 20 50 49 43 20 |ET UP.; THE PIC | 000000f0 54 4f 20 52 55 4e 20 46 52 4f 4d 20 41 4e 20 45 |TO RUN FROM AN E| 00000100 58 54 45 52 4e 41 4c 20 43 4c 4f 43 4b 20 41 4e |XTERNAL CLOCK AN| 00000110 44 20 52 45 4d 4f 56 45 0a 3b 20 54 48 45 20 50 |D REMOVE.; THE P| 00000120 52 45 53 43 41 4c 45 52 20 4f 50 54 49 4f 4e 2e |RESCALER OPTION.| 00000130 0a 3b 20 50 49 4e 20 38 20 20 2d 20 35 20 75 53 |.; PIN 8 - 5 uS| 00000140 20 50 55 4c 53 45 20 41 54 20 41 20 50 52 46 20 | PULSE AT A PRF | 00000150 4f 46 20 31 20 4b 48 7a 0a 3b 20 50 49 4e 20 31 |OF 1 KHz.; PIN 1| 00000160 30 20 2d 20 35 20 48 7a 20 53 51 55 41 52 45 20 |0 - 5 Hz SQUARE | 00000170 57 41 56 45 0a 3b 20 42 79 20 42 69 6c 6c 20 4a |WAVE.; By Bill J| 00000180 65 66 66 73 0a 3b 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d |effs.;==========| 00000190 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d |================| 000001a0 3d 3d 3d 0a 3b 0a 3b 20 20 20 20 20 20 20 44 45 |===.;.; DE| 000001b0 46 49 4e 49 54 49 4f 4e 53 0a 3b 0a 3b 2d 2d 2d |FINITIONS.;.;---| 000001c0 2d 2d 2d 2d 4d 49 43 52 4f 50 52 4f 43 45 53 53 |----MICROPROCESS| 000001d0 4f 52 2d 2d 2d 2d 2d 2d 2d 2d 0a 3b 0a 20 20 20 |OR--------.;. | 000001e0 20 20 20 20 20 4c 49 53 54 20 50 3d 31 36 43 38 | LIST P=16C8| 000001f0 34 0a 3b 0a 3b 2d 2d 2d 2d 2d 2d 2d 47 45 4e 45 |4.;.;-------GENE| 00000200 52 49 43 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d |RIC-------------| 00000210 2d 2d 0a 3b 0a 20 20 20 20 20 20 20 20 57 20 20 |--.;. W | 00000220 20 20 20 20 20 45 51 55 20 20 20 20 20 30 0a 20 | EQU 0. | 00000230 20 20 20 20 20 20 20 46 20 20 20 20 20 20 20 45 | F E| 00000240 51 55 20 20 20 20 20 31 0a 3b 0a 3b 2d 2d 2d 2d |QU 1.;.;----| 00000250 2d 2d 2d 52 45 47 49 53 54 45 52 53 2d 2d 2d 2d |---REGISTERS----| 00000260 2d 2d 2d 2d 2d 2d 2d 2d 2d 0a 3b 0a 20 20 20 20 |---------.;. | 00000270 20 20 20 20 52 54 43 43 20 20 20 20 45 51 55 20 | RTCC EQU | 00000280 20 20 20 20 48 27 30 31 27 20 20 20 3b 20 52 45 | H'01' ; RE| 00000290 47 49 53 54 45 52 53 20 44 45 46 49 4e 45 44 20 |GISTERS DEFINED | 000002a0 55 53 49 4e 47 0a 20 20 20 20 20 20 20 20 53 54 |USING. ST| 000002b0 41 54 55 53 20 20 45 51 55 20 20 20 20 20 48 27 |ATUS EQU H'| 000002c0 30 33 27 20 20 20 3b 20 48 45 58 20 4e 4f 54 41 |03' ; HEX NOTA| 000002d0 54 49 4f 4e 0a 20 20 20 20 20 20 20 20 50 4f 52 |TION. POR| 000002e0 54 42 20 20 20 45 51 55 20 20 20 20 20 48 27 30 |TB EQU H'0| 000002f0 36 27 0a 20 20 20 20 20 20 20 20 49 4e 54 43 4f |6'. INTCO| 00000300 4e 20 20 45 51 55 20 20 20 20 20 48 27 30 42 27 |N EQU H'0B'| 00000310 0a 20 20 20 20 20 20 20 20 57 53 41 56 45 20 20 |. WSAVE | 00000320 20 45 51 55 20 20 20 20 20 48 27 30 43 27 0a 20 | EQU H'0C'. | 00000330 20 20 20 20 20 20 20 53 53 41 56 45 20 20 20 45 | SSAVE E| 00000340 51 55 20 20 20 20 20 48 27 30 44 27 0a 20 20 20 |QU H'0D'. | 00000350 20 20 20 20 20 4f 50 54 52 45 47 20 20 45 51 55 | OPTREG EQU| 00000360 20 20 20 20 20 48 27 30 31 27 20 20 20 3b 20 41 | H'01' ; A| 00000370 43 54 55 41 4c 20 41 44 44 52 45 53 53 20 48 27 |CTUAL ADDRESS H'| 00000380 38 31 27 20 53 4f 20 53 45 54 20 54 4f 20 50 41 |81' SO SET TO PA| 00000390 47 45 20 31 0a 20 20 20 20 20 20 20 20 54 52 49 |GE 1. TRI| 000003a0 53 42 20 20 20 45 51 55 20 20 20 20 20 48 27 30 |SB EQU H'0| 000003b0 36 27 20 20 20 3b 20 41 43 54 55 41 4c 20 41 44 |6' ; ACTUAL AD| 000003c0 44 52 45 53 53 20 48 27 38 36 27 20 53 4f 20 53 |DRESS H'86' SO S| 000003d0 45 54 20 54 4f 20 50 41 47 45 20 31 0a 20 20 20 |ET TO PAGE 1. | 000003e0 20 20 20 20 20 44 53 45 43 20 20 20 20 45 51 55 | DSEC EQU| 000003f0 20 20 20 20 20 48 27 30 45 27 20 20 20 3b 20 44 | H'0E' ; D| 00000400 45 43 49 53 45 43 20 43 4f 55 4e 54 45 52 0a 3b |ECISEC COUNTER.;| 00000410 0a 3b 2d 2d 2d 2d 2d 2d 2d 53 54 41 54 55 53 20 |.;-------STATUS | 00000420 42 49 54 53 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 0a |BITS-----------.| 00000430 3b 0a 20 20 20 20 20 20 20 20 43 20 20 20 20 20 |;. C | 00000440 20 20 45 51 55 20 20 20 20 20 30 0a 20 20 20 20 | EQU 0. | 00000450 20 20 20 20 5a 20 20 20 20 20 20 20 45 51 55 20 | Z EQU | 00000460 20 20 20 20 32 0a 20 20 20 20 20 20 20 20 54 4f | 2. TO| 00000470 49 46 20 20 20 20 45 51 55 20 20 20 20 20 32 0a |IF EQU 2.| 00000480 20 20 20 20 20 20 20 20 52 50 30 20 20 20 20 20 | RP0 | 00000490 45 51 55 20 20 20 20 20 35 0a 20 20 20 20 20 20 |EQU 5. | 000004a0 20 20 54 4f 49 45 20 20 20 20 45 51 55 20 20 20 | TOIE EQU | 000004b0 20 20 35 0a 20 20 20 20 20 20 20 20 47 45 49 20 | 5. GEI | 000004c0 20 20 20 20 45 51 55 20 20 20 20 20 37 0a 3b 0a | EQU 7.;.| 000004d0 3b 2d 2d 2d 2d 2d 2d 2d 53 54 41 52 54 2d 2d 2d |;-------START---| 000004e0 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 0a 3b |--------------.;| 000004f0 0a 20 20 20 20 20 20 20 20 4f 52 47 20 20 20 20 |. ORG | 00000500 20 48 27 30 30 27 20 20 20 20 20 20 20 20 20 20 | H'00' | 00000510 20 3b 20 53 54 41 52 54 20 56 45 43 54 4f 52 0a | ; START VECTOR.| 00000520 20 20 20 20 20 20 20 20 47 4f 54 4f 20 20 20 20 | GOTO | 00000530 4d 41 49 4e 0a 3b 0a 20 20 20 20 20 20 20 20 4f |MAIN.;. O| 00000540 52 47 20 20 20 20 20 48 27 30 34 27 20 20 20 20 |RG H'04' | 00000550 20 20 20 20 20 20 20 3b 20 49 4e 54 45 52 52 55 | ; INTERRU| 00000560 50 54 20 56 45 43 54 4f 52 0a 20 20 20 20 20 20 |PT VECTOR. | 00000570 20 20 47 4f 54 4f 20 20 20 20 49 4e 54 52 50 54 | GOTO INTRPT| 00000580 0a 3b 0a 3b 2d 2d 2d 2d 2d 2d 2d 53 55 42 52 4f |.;.;-------SUBRO| 00000590 55 54 49 4e 45 53 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d |UTINES----------| 000005a0 2d 0a 3b 0a 20 20 20 20 20 20 20 20 4f 52 47 20 |-.;. ORG | 000005b0 20 20 20 20 48 27 30 36 27 0a 3b 0a 3b 2d 2d 2d | H'06'.;.;---| 000005c0 2d 2d 2d 2d 49 4e 49 54 49 41 4c 49 53 45 2d 2d |----INITIALISE--| 000005d0 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 0a 3b 0a 49 4e 49 |----------.;.INI| 000005e0 54 20 20 20 20 4d 4f 56 4c 57 20 20 20 30 0a 20 |T MOVLW 0. | 000005f0 20 20 20 20 20 20 20 4d 4f 56 57 46 20 20 20 50 | MOVWF P| 00000600 4f 52 54 42 20 20 20 20 20 20 20 20 20 20 20 3b |ORTB ;| 00000610 20 43 4c 45 41 52 20 50 4f 52 54 20 42 20 46 4f | CLEAR PORT B FO| 00000620 52 20 43 4c 45 41 4e 20 53 54 41 52 54 0a 20 20 |R CLEAN START. | 00000630 20 20 20 20 20 20 4d 4f 56 4c 57 20 20 20 42 27 | MOVLW B'| 00000640 30 30 30 30 30 30 30 31 27 20 20 20 20 20 3b 20 |00000001' ; | 00000650 53 45 54 20 50 52 45 53 43 41 4c 45 52 20 54 4f |SET PRESCALER TO| 00000660 20 44 49 56 20 42 59 20 34 0a 20 20 20 20 20 20 | DIV BY 4. | 00000670 20 20 42 53 46 20 20 20 20 20 53 54 41 54 55 53 | BSF STATUS| 00000680 2c 52 50 30 20 20 20 20 20 20 3b 20 53 45 54 20 |,RP0 ; SET | 00000690 46 4f 52 20 52 45 47 49 53 54 45 52 20 50 41 47 |FOR REGISTER PAG| 000006a0 45 20 31 0a 20 20 20 20 20 20 20 20 4d 4f 56 57 |E 1. MOVW| 000006b0 46 20 20 20 4f 50 54 52 45 47 20 20 20 20 20 20 |F OPTREG | 000006c0 20 20 20 20 3b 20 4f 50 54 52 45 47 20 49 53 20 | ; OPTREG IS | 000006d0 49 4e 20 50 41 47 45 20 31 0a 20 20 20 20 20 20 |IN PAGE 1. | 000006e0 20 20 4d 4f 56 4c 57 20 20 20 30 20 20 20 20 20 | MOVLW 0 | 000006f0 20 20 20 20 20 20 20 20 20 20 3b 20 53 45 54 20 | ; SET | 00000700 50 4f 52 54 42 20 54 4f 20 4f 55 54 50 55 54 0a |PORTB TO OUTPUT.| 00000710 20 20 20 20 20 20 20 20 4d 4f 56 57 46 20 20 20 | MOVWF | 00000720 54 52 49 53 42 20 20 20 20 20 20 20 20 20 20 20 |TRISB | 00000730 3b 20 54 52 49 53 42 20 49 53 20 49 4e 20 50 41 |; TRISB IS IN PA| 00000740 47 45 20 31 0a 20 20 20 20 20 20 20 20 42 43 46 |GE 1. BCF| 00000750 20 20 20 20 20 53 54 41 54 55 53 2c 52 50 30 20 | STATUS,RP0 | 00000760 20 20 20 20 20 3b 20 52 45 54 55 52 4e 20 54 4f | ; RETURN TO| 00000770 20 50 41 47 45 20 30 0a 20 20 20 20 20 20 20 20 | PAGE 0. | 00000780 4d 4f 56 4c 57 20 20 20 31 30 30 0a 20 20 20 20 |MOVLW 100. | 00000790 20 20 20 20 4d 4f 56 57 46 20 20 20 44 53 45 43 | MOVWF DSEC| 000007a0 20 20 20 20 20 20 20 20 20 20 20 20 3b 20 4c 4f | ; LO| 000007b0 41 44 20 44 45 43 49 53 45 43 20 43 4f 55 4e 54 |AD DECISEC COUNT| 000007c0 45 52 0a 20 20 20 20 20 20 20 20 42 53 46 20 20 |ER. BSF | 000007d0 20 20 20 49 4e 54 43 4f 4e 2c 54 4f 49 45 20 20 | INTCON,TOIE | 000007e0 20 20 20 3b 20 54 49 4d 45 52 20 49 4e 54 45 52 | ; TIMER INTER| 000007f0 52 55 50 54 20 45 4e 41 42 4c 45 0a 20 20 20 20 |RUPT ENABLE. | 00000800 20 20 20 20 42 53 46 20 20 20 20 20 49 4e 54 43 | BSF INTC| 00000810 4f 4e 2c 47 45 49 20 20 20 20 20 20 3b 20 47 4c |ON,GEI ; GL| 00000820 4f 42 41 4c 20 49 4e 54 45 52 52 55 50 54 20 45 |OBAL INTERRUPT E| 00000830 4e 41 42 4c 45 0a 20 20 20 20 20 20 20 20 52 45 |NABLE. RE| 00000840 54 55 52 4e 0a 3b 0a 3b 2d 2d 2d 2d 2d 2d 2d 53 |TURN.;.;-------S| 00000850 45 52 56 49 43 45 20 49 4e 54 45 52 52 55 50 54 |ERVICE INTERRUPT| 00000860 2d 2d 2d 2d 2d 0a 3b 0a 49 4e 54 52 50 54 20 20 |-----.;.INTRPT | 00000870 4d 4f 56 57 46 20 20 20 57 53 41 56 45 20 20 20 |MOVWF WSAVE | 00000880 20 20 20 20 20 20 20 20 3b 20 53 41 56 45 20 57 | ; SAVE W| 00000890 20 52 45 47 49 53 54 45 52 0a 20 20 20 20 20 20 | REGISTER. | 000008a0 20 20 53 57 41 50 46 20 20 20 53 54 41 54 55 53 | SWAPF STATUS| 000008b0 2c 57 20 20 20 20 20 20 20 20 3b 20 53 54 41 54 |,W ; STAT| 000008c0 55 53 20 57 49 4c 4c 20 4e 4f 54 20 42 45 20 43 |US WILL NOT BE C| 000008d0 48 41 4e 47 45 44 0a 20 20 20 20 20 20 20 20 4d |HANGED. M| 000008e0 4f 56 57 46 20 20 20 53 53 41 56 45 20 20 20 20 |OVWF SSAVE | 000008f0 20 20 20 20 20 20 20 3b 20 53 41 56 45 20 53 54 | ; SAVE ST| 00000900 41 54 55 53 20 52 45 47 49 53 54 45 52 0a 20 20 |ATUS REGISTER. | 00000910 20 20 20 20 20 20 42 43 46 20 20 20 20 20 49 4e | BCF IN| 00000920 54 43 4f 4e 2c 54 4f 49 46 20 20 20 20 20 3b 20 |TCON,TOIF ; | 00000930 43 4c 45 41 52 20 49 4e 54 45 52 52 55 50 54 20 |CLEAR INTERRUPT | 00000940 46 4c 41 47 0a 3b 0a 20 20 20 20 20 20 20 20 4d |FLAG.;. M| 00000950 4f 56 4c 57 20 20 20 48 27 30 34 27 20 20 20 20 |OVLW H'04' | 00000960 20 20 20 20 20 20 20 3b 20 4c 4f 41 44 20 4d 41 | ; LOAD MA| 00000970 53 4b 20 54 4f 20 54 4f 47 47 4c 45 20 42 49 54 |SK TO TOGGLE BIT| 00000980 20 32 0a 20 20 20 20 20 20 20 20 58 4f 52 57 46 | 2. XORWF| 00000990 20 20 20 50 4f 52 54 42 2c 46 20 20 20 20 20 20 | PORTB,F | 000009a0 20 20 20 3b 20 41 4e 44 20 54 4f 47 47 4c 45 20 | ; AND TOGGLE | 000009b0 49 54 0a 20 20 20 20 20 20 20 20 4e 4f 50 20 20 |IT. NOP | 000009c0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 000009d0 20 20 20 3b 20 41 4e 44 20 44 45 4c 41 59 20 46 | ; AND DELAY F| 000009e0 4f 52 20 35 20 43 4c 4f 43 4b 20 43 59 43 4c 45 |OR 5 CLOCK CYCLE| 000009f0 53 0a 20 20 20 20 20 20 20 20 4e 4f 50 0a 20 20 |S. NOP. | 00000a00 20 20 20 20 20 20 4e 4f 50 0a 20 20 20 20 20 20 | NOP. | 00000a10 20 20 4e 4f 50 0a 20 20 20 20 20 20 20 20 58 4f | NOP. XO| 00000a20 52 57 46 20 20 20 50 4f 52 54 42 2c 46 20 20 20 |RWF PORTB,F | 00000a30 20 20 20 20 20 20 3b 20 41 4e 44 20 52 45 54 55 | ; AND RETU| 00000a40 52 4e 20 46 4f 52 20 35 20 43 59 43 4c 45 20 50 |RN FOR 5 CYCLE P| 00000a50 55 4c 53 45 0a 20 20 20 20 20 20 20 20 4d 4f 56 |ULSE. MOV| 00000a60 4c 57 20 20 20 35 20 20 20 20 20 20 20 20 20 20 |LW 5 | 00000a70 20 20 20 20 20 3b 20 32 35 36 2d 28 32 35 30 2d | ; 256-(250-| 00000a80 31 34 29 3d 43 4f 55 4e 54 20 55 50 20 46 52 4f |14)=COUNT UP FRO| 00000a90 4d 20 32 30 2f 34 0a 20 20 20 20 20 20 20 20 4d |M 20/4. M| 00000aa0 4f 56 57 46 20 20 20 52 54 43 43 20 20 20 20 20 |OVWF RTCC | 00000ab0 20 20 20 20 20 20 20 3b 20 52 45 4c 4f 41 44 20 | ; RELOAD | 00000ac0 52 54 43 43 0a 20 20 20 20 20 20 20 20 44 45 43 |RTCC. DEC| 00000ad0 46 20 20 20 20 44 53 45 43 2c 46 20 20 20 20 20 |F DSEC,F | 00000ae0 20 20 20 20 20 3b 20 44 45 43 52 45 4d 45 4e 54 | ; DECREMENT| 00000af0 20 43 4f 55 4e 54 45 52 0a 20 20 20 20 20 20 20 | COUNTER. | 00000b00 20 42 54 46 53 43 20 20 20 53 54 41 54 55 53 2c | BTFSC STATUS,| 00000b10 5a 20 20 20 20 20 20 20 20 3b 20 53 4b 49 50 20 |Z ; SKIP | 00000b20 49 46 20 4e 4f 54 20 5a 45 52 4f 0a 20 20 20 20 |IF NOT ZERO. | 00000b30 20 20 20 20 43 41 4c 4c 20 20 20 20 54 4f 47 47 | CALL TOGG| 00000b40 4c 45 20 20 20 20 20 20 20 20 20 20 3b 20 52 45 |LE ; RE| 00000b50 53 45 54 20 43 4f 55 4e 54 45 52 20 41 4e 44 20 |SET COUNTER AND | 00000b60 54 4f 47 47 4c 45 20 4f 55 54 50 55 54 0a 3b 0a |TOGGLE OUTPUT.;.| 00000b70 20 20 20 20 20 20 20 20 53 57 41 50 46 20 20 20 | SWAPF | 00000b80 53 53 41 56 45 2c 57 20 20 20 20 20 20 20 20 20 |SSAVE,W | 00000b90 3b 20 52 45 53 54 4f 52 45 20 53 54 41 54 55 53 |; RESTORE STATUS| 00000ba0 20 57 49 54 48 4f 55 54 0a 20 20 20 20 20 20 20 | WITHOUT. | 00000bb0 20 4d 4f 56 57 46 20 20 20 53 54 41 54 55 53 20 | MOVWF STATUS | 00000bc0 20 20 20 20 20 20 20 20 20 3b 20 43 48 41 4e 47 | ; CHANG| 00000bd0 49 4e 47 20 41 4e 59 20 53 54 41 54 55 53 20 42 |ING ANY STATUS B| 00000be0 49 54 53 0a 20 20 20 20 20 20 20 20 53 57 41 50 |ITS. SWAP| 00000bf0 46 20 20 20 57 53 41 56 45 2c 46 20 20 20 20 20 |F WSAVE,F | 00000c00 20 20 20 20 3b 20 52 45 53 54 4f 52 45 20 57 20 | ; RESTORE W | 00000c10 52 45 47 49 53 54 45 52 20 57 49 54 48 4f 55 54 |REGISTER WITHOUT| 00000c20 0a 20 20 20 20 20 20 20 20 53 57 41 50 46 20 20 |. SWAPF | 00000c30 20 57 53 41 56 45 2c 57 20 20 20 20 20 20 20 20 | WSAVE,W | 00000c40 20 3b 20 43 48 41 4e 47 49 4e 47 20 41 4e 59 20 | ; CHANGING ANY | 00000c50 53 54 41 54 55 53 20 42 49 54 53 0a 20 20 20 20 |STATUS BITS. | 00000c60 20 20 20 20 52 45 54 46 49 45 20 20 20 20 20 20 | RETFIE | 00000c70 20 20 20 20 20 20 20 20 20 20 20 20 3b 20 41 4e | ; AN| 00000c80 44 20 54 48 45 4e 20 52 45 54 55 52 4e 20 46 52 |D THEN RETURN FR| 00000c90 4f 4d 20 49 4e 54 45 52 52 55 50 54 0a 3b 0a 3b |OM INTERRUPT.;.;| 00000ca0 2d 2d 2d 2d 2d 2d 2d 50 52 4f 43 45 53 53 20 44 |-------PROCESS D| 00000cb0 45 43 49 53 45 43 4f 4e 44 2d 2d 2d 0a 3b 0a 54 |ECISECOND---.;.T| 00000cc0 4f 47 47 4c 45 20 20 4d 4f 56 4c 57 20 20 20 48 |OGGLE MOVLW H| 00000cd0 27 36 34 27 0a 20 20 20 20 20 20 20 20 4d 4f 56 |'64'. MOV| 00000ce0 57 46 20 20 20 44 53 45 43 0a 20 20 20 20 20 20 |WF DSEC. | 00000cf0 20 20 4d 4f 56 4c 57 20 20 20 48 27 31 30 27 0a | MOVLW H'10'.| 00000d00 20 20 20 20 20 20 20 20 58 4f 52 57 46 20 20 20 | XORWF | 00000d10 50 4f 52 54 42 2c 46 0a 20 20 20 20 20 20 20 20 |PORTB,F. | 00000d20 52 45 54 55 52 4e 0a 3b 0a 3b 2d 2d 2d 2d 2d 2d |RETURN.;.;------| 00000d30 2d 50 52 4f 47 52 41 4d 20 53 54 41 52 54 53 20 |-PROGRAM STARTS | 00000d40 48 45 52 45 2d 2d 2d 0a 3b 0a 4d 41 49 4e 20 20 |HERE---.;.MAIN | 00000d50 20 20 43 41 4c 4c 20 20 20 20 49 4e 49 54 0a 4c | CALL INIT.L| 00000d60 4f 4f 50 20 20 20 20 4e 4f 50 0a 20 20 20 20 20 |OOP NOP. | 00000d70 20 20 20 47 4f 54 4f 20 20 20 20 4c 4f 4f 50 0a | GOTO LOOP.| 00000d80 45 4e 44 0a |END.| 00000d84
.