Hi Everyone!
I wanna make siren sound with 16f628a and timer0.
I find on the web and found the tmr0 solution. I did make program, but can't take good result.
Do you have sample program for me with tmr0 interrupt.
Thank you.
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Hi Everyone!
I wanna make siren sound with 16f628a and timer0.
I find on the web and found the tmr0 solution. I did make program, but can't take good result.
Do you have sample program for me with tmr0 interrupt.
Thank you.
Post up the code you have (use the "code /code " tags) and state what the actual problem is and I'm sure someone will offer assistance
Hi I am using tmro interrupt.Quote:
Originally Posted by Scampy
My program is;
anyone can help me for this?Code:@ __config _INTRC_OSC_NOCLKOUT & _WDT_OFF & _PWRTE_ON & _MCLRE_OFF &_BODEN_ON & _LVP_OFF & _DATA_CP_OFFON INTERRUPT GoTo VAIL
OPTION_REG=000001
define OSC 4
CMCON=7
INTCON=100000
trisa=0
trisb=0
porta=0
portb=0
SYMBOL SES=PORTA.1
t var word
a1 var byte
a var byte
x var byte
a=0:a1=55:t=0:x=0
tmr0=55
wail:
goto wail
VAIL:
disable
TOGGLE SES
t=t+1
if t=20 and a=0 then
t=0
a1=a1+1
if a1>242 then a=1
endif
if t=125 and a=1 then
t=0
a1=a1+1
if a1>245 then a=2
endif
if t=125 and a=2 then
t=0
a1=a1-1
if a1<242 then a=3
endif
if t=20 and a=3 then
t=0
a1=a1-1
if a1=<55 then a=0
endif
tmr0=a1
INTCON.2=0
resume
enable
end
well this may be one reason... it's looping but doing nothing in-betweenCode:a=0:a1=55:t=0:x=0
tmr0=55
wail:
goto wail
VAIL:
disable
I think that is ok, it loops until tmr0 interrupts on overflow.Quote:
Originally Posted by Scampy
I have never used ON INTERRUPT, but I see some mistakes probably from cut and paste. ON INTERRUPT should be on a separate line, not in the configurations
OPTION_REG and INTCON need % in front of the binary numbers
enable at the end of the code will never happen, since resume returns us to the main program.
What else?
Code:@ __config _INTRC_OSC_NOCLKOUT & _WDT_OFF & _PWRTE_ON & _MCLRE_OFF &_BODEN_ON & _LVP_OFF & _DATA_CP_OFFON INTERRUPT GoTo VAIL
OPTION_REG=000001
define OSC 4
CMCON=7
INTCON=100000
trisa=0
trisb=0
porta=0
portb=0
SYMBOL SES=PORTA.1
t var word
a1 var byte
a var byte
x var byte
a=0:a1=55:t=0:x=0
tmr0=55
wail:
goto wail
VAIL:
disable
TOGGLE SES
t=t+1
if t=20 and a=0 then
t=0
a1=a1+1
if a1>242 then a=1
endif
if t=125 and a=1 then
t=0
a1=a1+1
if a1>245 then a=2
endif
if t=125 and a=2 then
t=0
a1=a1-1
if a1<242 then a=3
endif
if t=20 and a=3 then
t=0
a1=a1-1
if a1=<55 then a=0
endif
tmr0=a1
INTCON.2=0
resume
enable
end
Hi MarksQuote:
Originally Posted by mark_s
You are right. İt is problem related to copy paste selection.
I looked to my program on the editor mode, it is right.
I am using this program on the isus simulation program.
All commands is good, without one position.
High frequency sound is very bad. I am trying to make good sound this frequency.
I asked you , if you have sapmle code related this program pls share for me.
Thank you for your interest.
I found this on the net, no idea if it works, but the code is very well commented and may help you with your project. Note the hardware too
https://www.scribd.com/doc/103363423...icrocontroller
And another project, but in mikroC which may be easier to convert to PBP http://www.electroschematics.com/873...ecurity-alarm/
Hi Scampy;Quote:
Originally Posted by Scampy
Thank you for your solutions.
I saw this project on the web, these are related , simple siren sound.
I wanna professional siren sound. I saw more softwear on the web, all softwear writing asm language.
Then I decide to learn asm.
İt is mine solutions.
Thank you :)
I think this the one you are trying to do?
https://www.youtube.com/watch?v=tcrrrRKwqb8
It would be fun to port this to pic basic. I found the original assembly program for a pic16f84. The guy in the video uses a pic16f676. You can find more info if you google "Pic micro Multi Siren"
I don't have time to try it right now
Code:
;-----------------------------------------------------------------------------
;LABLE OPCODE OPERAND COMMENTS
list R=DEC ;Set radix to decimal
list P=16F84A ;Set device to pic16F84
list F=INHX8m ;Set format intel 8 bit merged
; list F=picice ;picice format
;------------------------------------------------------------------------------
;SETTING UP LABLES
;
port_a equ 5h ;equate port a
port_b equ 6h ;equate port b
same equ 1 ;same register
_pc equ 02h ;program counter
_rtcc equ 01h ;rtcc
indirect equ 00h ;indirect address contents
_fsr equ 04h ;file select register
_status equ 03h ;status register
_carry equ 0 ;carry flag
_zero equ 2 ;zero flag
; equ 10h ;
; equ 11h ;
; equ 12h ;
_lenth equ 13h ;
; equ 17h ;
temp1 equ 14h ;
temp2 equ 15h ;
temp3 equ 16h ;
temp4 equ 1Ah ;
temp5 equ 1Bh ;
dipval equ 1Ch ;
; equ 1Dh ;
; equ 1Eh ;
; equ 1Fh ;
; equ 0Fh ;
; equ 0Dh ;
; equ 0Bh ;
; equ 09h ;
; equ 08h ;
; equ 0Ah ;
; equ 0Eh ;
_flags equ 0Ch ;flag register
; equ 18h ;
; equ 19h ;
;-----------------------------------------------------------------------------
;port b pin definitions
;--------------------
; equ 3 ;
; equ 2 ;
; equ 1 ;
sir equ 0 ;siren drive out
;------------------------------------------------------------------------------
;flags
; 0 0=siren sweep off
; 1=siren sweep on
;------------------------------------------------------------------------------
; 1 0=
; 1=
;------------------------------------------------------------------------------
; 2 0=
; 1=
;------------------------------------------------------------------------------
; 3 0=
; 1=
;------------------------------------------------------------------------------
; 4 0=
; 1=
;-----------------------------------------------------------------------------
; 5 0=
; 1=
;------------------------------------------------------------------------------
; 6 0=
; 1=
;------------------------------------------------------------------------------
; 7 0=
; 1=
;------------------------------------------------------------------------------
;page 0
;------------------------------------------------------------------------------
ORG 000h ;originate code here
;------------------------------------------------------------------------------
;Codes start here
init movlw B'01111111' ;7 output
tris port_b ;
clrf port_b ;resetting port b
movlw B'11111111' ;
tris port_a ;
clrf port_a ;resetting port a
movlw B'00001111' ;setup wdt 128:1
option ;pul ups off int clock enabled
clrf _flags ;clear all flags
;----------------------------------------------------------------------------
diptest movf port_b,w ;get dip value
movwf dipval ;
comf dipval,same ;
bcf dipval,7 ;mask
bcf dipval,6 ;
bcf dipval,5 ;
bcf dipval,4 ;
movlw 15 ;
subwf dipval,w ;
btfsc _status,_carry ;set is pos
goto op ;
movlw 14 ;
subwf dipval,w ;
btfsc _status,_carry ;set is pos
goto op14 ;
movlw 13 ;
subwf dipval,w ;
btfsc _status,_carry ;set is pos
goto op13 ;
movlw 12 ;
subwf dipval,w ;
btfsc _status,_carry ;set is pos
goto op12 ;
movlw 11 ;
subwf dipval,w ;
btfsc _status,_carry ;set is pos
goto op11 ;
movlw 10 ;
subwf dipval,w ;
btfsc _status,_carry ;set is pos
goto op10 ;
movlw 9 ;
subwf dipval,w ;
btfsc _status,_carry ;set is pos
goto op9 ;
movlw 8 ;
subwf dipval,w ;
btfsc _status,_carry ;set is pos
goto op8 ;
movlw 7 ;
subwf dipval,w ;
btfsc _status,_carry ;set is pos
goto op7 ;
movlw 6 ;
subwf dipval,w ;
btfsc _status,_carry ;set is pos
goto op6 ;
movlw 5 ;
subwf dipval,w ;
btfsc _status,_carry ;set is pos
goto op5 ;
movlw 4 ;
subwf dipval,w ;
btfsc _status,_carry ;set is pos
goto op4 ;
movlw 3 ;
subwf dipval,w ;
btfsc _status,_carry ;set is pos
goto op3 ;
movlw 2 ;
subwf dipval,w ;
btfsc _status,_carry ;set is pos
goto op2 ;
movlw 1 ;
subwf dipval,w ;
btfsc _status,_carry ;set is pos
goto op1 ;
goto op ;
;---------------------------------------------------------------------------
op bsf _flags,0 ;fast sweep
movlw 250 ;
movwf temp2 ;sweep = 255
movlw 5 ;255 /10 th = variable rate 5
movwf _lenth ;
movlw 3 ;
movwf temp3 ;pitch preset to 25
siren bsf port_b,7 ;beeper on
call pit ;variable pitch
bcf port_b,7 ;beeper off
call pit ;variable pitch
decfsz temp2,same ;sweep timer
goto var ;
movlw 250 ;reset sweep timer
movwf temp2 ;
goto tog ;toggle if sweep over
;--------------------------------------------------------------------------
tog btfsc _flags,0 ;test if sweep off
goto down ;pitch down
goto up ;pitch up
down bcf _flags,0 ;
goto siren ;
up bsf _flags,0 ;
goto siren ;
;---------------------------------------------------------------------------
var decfsz _lenth,same ;
goto siren ;
btfsc _flags,0 ;test if sweep up or down
goto re ;
decfsz temp3,same ;
goto qw1 ;
bsf _flags,0 ;
qw1 movlw 5 ;reset /10 5
movwf _lenth ;
goto siren ;
re incf temp3,same ;
movlw 5 ;
movwf _lenth ;reset /10 5
goto siren ;
;---------------------------------------------------------------------------
pit movf temp3,w ;
movwf temp4 ;
g clrwdt ;kick dog
decfsz temp4,same ;
goto g ;
retlw 0 ;
;--------------------------------------------------------------------------
;---------------------------------------------------------------------------
;---------------------------------------------------------------------------
;---------------------------------------------------------------------------
op1 bsf _flags,0 ;very slow sweep
movlw 230 ;
movwf temp2 ;sweep = 255
movlw 3 ;255 /10 th = variable rate
movwf _lenth ;
movlw 85 ;
movwf temp3 ;pitch preset to 25
siren1 bsf port_b,7 ;beeper on
call pit ;variable pitch
bcf port_b,7 ;beeper off
call pit ;variable pitch
decfsz temp2,same ;sweep timer
goto var1 ;
movlw 230 ;reset sweep timer
movwf temp2 ;
goto tog1 ;toggle if sweep over
;--------------------------------------------------------------------------
tog1 btfsc _flags,0 ;test if sweep off
goto down1 ;pitch down
goto up1 ;pitch up
down1 bcf _flags,0 ;
goto siren1 ;
up1 bsf _flags,0 ;
goto siren1 ;
;---------------------------------------------------------------------------
var1 decfsz _lenth,same ;
goto siren1 ;
btfsc _flags,0 ;test if sweep up or down
goto re1 ;
decf temp3,same ;
movlw 3 ;reset /10
movwf _lenth ;
goto siren1 ;
re1 incf temp3,same ;
movlw 3 ;
movwf _lenth ;reset /10
goto siren1 ;
;---------------------------------------------------------------------------
;---------------------------------------------------------------------------
;---------------------------------------------------------------------------
op2 bsf _flags,0 ;medium sweep
movlw 10 ;
movwf temp3 ;pitch preset to 25
siren2 bsf port_b,7 ;beeper on
call pit ;variable pitch
bcf port_b,7 ;beeper off
call pit ;variable pitch
goto var2 ;
;---------------------------------------------------------------------------
var2 btfsc _flags,0 ;test if sweep up or down
goto re2 ;
decfsz temp3,same ;
goto siren2 ;
bsf _flags,0 ;
incf temp3,same ;
goto siren2 ;
re2 incf temp3,same ;
movlw 150 ;
subwf temp3,w ;
btfsc _status,_carry ;set if pos
bcf _flags,0 ;
goto siren2 ;
;---------------------------------------------------------------------------
;---------------------------------------------------------------------------
;---------------------------------------------------------------------------
op3 bsf _flags,0 ;police siren
movlw 5 ;sweep delay timer
movwf temp1 ;
movlw 255 ;
movwf temp2 ;sweep = 255
movlw 255 ;
movwf temp3 ;pitch preset to 25
siren3 bsf port_b,7 ;beeper on
call pit ;variable pitch
bcf port_b,7 ;beeper off
call pit ;variable pitch
decfsz temp1,same ;delay sweep
goto siren3 ;
movlw 5 ;reset delayed sweep
movwf temp1 ;
btfsc _flags,0 ;test if up or down sweep
goto m1 ;
goto m2 ;
m1 decfsz temp2,same ;sweep timer
goto var3 ;
goto tog3 ;toggle if sweep over
m2 movlw 5 ;
subwf temp2,same ;
movf temp2,w ;
btfsc _status,_zero ;
goto var3 ;
goto tog3 ;toggle if sweep over
;--------------------------------------------------------------------------
tog3 btfsc _flags,0 ;test if sweep off
goto down3 ;pitch down
goto up3 ;pitch up
down3 bcf _flags,0 ;
goto siren3 ;
up3 bsf _flags,0 ;
goto siren3 ;
;---------------------------------------------------------------------------
var3 btfsc _flags,0 ;test if sweep up or down
goto re3 ;
decf temp3,same ;
goto siren3 ;
re3 movlw 255 ;
subwf temp3,w ;
btfsc _status,_carry ;set is positive
bcf _flags,0 ;
incf temp3,same ;
goto siren5 ;
;---------------------------------------------------------------------------
;---------------------------------------------------------------------------
;---------------------------------------------------------------------------
op4 bsf _flags,0 ;slow rise
movlw 6 ;sweep delay timer
movwf temp1 ;
movlw 255 ;
movwf temp2 ;sweep = 255
movlw 255 ;
movwf temp3 ;pitch preset to 25
siren4 bsf port_b,7 ;beeper on
call pit ;variable pitch
bcf port_b,7 ;beeper off
call pit ;variable pitch
decfsz temp1,same ;delay sweep
goto siren4 ;
movlw 6 ;reset delayed sweep
movwf temp1 ;
btfss _flags,0 ;test if up or down sweep
goto m3 ;
goto m4 ;
m3 decfsz temp2,same ;sweep timer
goto var4 ;
goto tog4 ;toggle if sweep over
m4 movlw 5 ;
subwf temp2,same ;
movf temp2,w ;
btfsc _status,_zero ;
goto var4 ;
goto tog4 ;toggle if sweep over
;--------------------------------------------------------------------------
tog4 btfsc _flags,0 ;test if sweep off
goto down4 ;pitch down
goto up4 ;pitch up
down4 bcf _flags,0 ;
goto siren4 ;
up4 bsf _flags,0 ;
goto siren4 ;
;---------------------------------------------------------------------------
var4 btfsc _flags,0 ;test if sweep up or down
goto re4 ;
decf temp3,same ;
goto siren4 ;
re4 movlw 255 ;
subwf temp3,w ;
btfsc _status,_carry ;set is positive
bcf _flags,0 ;
incf temp3,same ;
goto siren5 ;
;---------------------------------------------------------------------------
;---------------------------------------------------------------------------
;---------------------------------------------------------------------------
op5 bsf _flags,0 ;ultra low sweep (air raid)
movlw 20 ;sweep delay timer
movwf temp1 ;
movlw 255 ;
movwf temp2 ;sweep = 255
movlw 255 ;
movwf temp3 ;pitch preset to 25
siren5 bsf port_b,7 ;beeper on
call pit ;variable pitch
bcf port_b,7 ;beeper off
call pit ;variable pitch
decfsz temp1,same ;delay sweep
goto siren5 ;
movlw 20 ;reset delayed sweep
movwf temp1 ;
decfsz temp2,same ;sweep timer
goto var5 ;
goto tog5 ;toggle if sweep over
;--------------------------------------------------------------------------
tog5 btfsc _flags,0 ;test if sweep off
goto down5 ;pitch down
goto up5 ;pitch up
down5 bcf _flags,0 ;
goto siren5 ;
up5 bsf _flags,0 ;
goto siren5 ;
;---------------------------------------------------------------------------
var5 btfsc _flags,0 ;test if sweep up or down
goto re5 ;
decf temp3,same ;
goto siren5 ;
re5 movlw 255 ;
subwf temp3,w ;
btfsc _status,_carry ;set is positive
bcf _flags,0 ;
incf temp3,same ;
goto siren5 ;
;----------------------------------------------------------------------------
;----------------------------------------------------------------------------
;---------------------------------------------------------------------------
op6 bsf _flags,0 ;two tone high pitch
movlw 2 ;sweep delay timer
movwf temp1 ;
movlw 255 ;
movwf temp2 ;sweep = 255
movlw 50 ;
movwf temp3 ;pitch preset to 25
siren6 bsf port_b,7 ;beeper on
call pit ;variable pitch
bcf port_b,7 ;beeper off
call pit ;variable pitch
decfsz temp1,same ;delay sweep
goto siren6 ;
movlw 2 ;reset delayed sweep
movwf temp1 ;
decfsz temp2,same ;sweep timer
goto siren6 ;
btfsc _flags,0 ;test if high or low
goto m5 ;
goto m6 ;
m5 movlw 20 ;
movwf temp3 ;
bcf _flags,0 ;
goto siren6 ;
m6 movlw 50 ;
movwf temp3 ;
bsf _flags,0 ;
goto siren6 ;
;---------------------------------------------------------------------------
;---------------------------------------------------------------------------
;----------------------------------------------------------------------------
op7 bsf _flags,0 ;continues
movlw 40 ;
movwf temp3 ;pitch preset to 25
siren7 bsf port_b,7 ;beeper on
call pit ;variable pitch
bcf port_b,7 ;beeper off
call pit ;variable pitch
goto siren7 ;
;----------------------------------------------------------------------------
;----------------------------------------------------------------------------
;----------------------------------------------------------------------------
op8 movlw 40 ;telephone
movwf temp3 ;pitch preset to 25
movlw 100 ;
movwf _lenth ;lenth timer
siren8 bsf port_b,7 ;beeper on
call pit ;variable pitch
bcf port_b,7 ;beeper off
call pit ;variable pitch
decfsz _lenth,same ;
goto siren8 ;
movlw 100 ;reset lenth timer
movwf _lenth ;
movlw 50 ;
movwf temp3 ;pitch preset to 25
siren9 bsf port_b,7 ;beeper on
call pit ;variable pitch
bcf port_b,7 ;beeper off
call pit ;variable pitch
decfsz _lenth,same ;
goto siren9 ;
movlw 100 ;reset lenth timer
movwf _lenth ;
goto op8 ;
;---------------------------------------------------------------------------
;---------------------------------------------------------------------------
;---------------------------------------------------------------------------
op9 movlw 40 ;buzzer
movwf temp3 ;pitch preset to 25
movlw 2 ;
movwf _lenth ;lenth timer
siren10 bsf port_b,7 ;beeper on
call pit ;variable pitch
bcf port_b,7 ;beeper off
call pit ;variable pitch
decfsz _lenth,same ;
goto siren10 ;
movlw 2 ;reset lenth timer
movwf _lenth ;
movlw 255 ;
movwf temp3 ;pitch preset to 25
siren11 bsf port_b,7 ;beeper on
call pit ;variable pitch
bcf port_b,7 ;beeper off
call pit ;variable pitch
decfsz _lenth,same ;
goto siren11 ;
movlw 2 ;reset lenth timer
movwf _lenth ;
goto op9 ;
;----------------------------------------------------------------------------
;----------------------------------------------------------------------------
;---------------------------------------------------------------------------
op10 bsf _flags,0 ;laser shoot fast
movlw 1 ;sweep delay timer
movwf temp1 ;
movlw 255 ;
movwf temp2 ;sweep = 255
movlw 255 ;
movwf temp3 ;pitch preset to 25
siren12 bsf port_b,7 ;beeper on
call pit ;variable pitch
bcf port_b,7 ;beeper off
call pit ;variable pitch
decfsz temp1,same ;delay sweep
goto siren12 ;
movlw 1 ;reset delayed sweep
movwf temp1 ;
btfsc _flags,0 ;test if up or down sweep
goto m11 ;
goto m12 ;
m11 decfsz temp2,same ;sweep timer
goto var11 ;
goto tog13 ;toggle if sweep over
m12 movlw 5 ;
subwf temp2,same ;
movf temp2,w ;
btfsc _status,_zero ;
goto var11 ;
goto tog13 ;toggle if sweep over
;--------------------------------------------------------------------------
tog13 btfsc _flags,0 ;test if sweep off
goto down13 ;pitch down
goto up13 ;pitch up
down13 bcf _flags,0 ;
goto siren12 ;
up13 bsf _flags,0 ;
goto siren12 ;
;---------------------------------------------------------------------------
var11 btfsc _flags,0 ;test if sweep up or down
goto re13 ;
decf temp3,same ;
goto siren12 ;
re13 movlw 255 ;
subwf temp3,w ;
btfsc _status,_carry ;set is positive
bcf _flags,0 ;
incf temp3,same ;
goto siren12 ;
;---------------------------------------------------------------------------
;---------------------------------------------------------------------------
;---------------------------------------------------------------------------
op11 bsf _flags,0 ;laser shoot slow
movlw 2 ;sweep delay timer
movwf temp1 ;
movlw 255 ;
movwf temp2 ;sweep = 255
movlw 255 ;
movwf temp3 ;pitch preset to 25
siren13 bsf port_b,7 ;beeper on
call pit ;variable pitch
bcf port_b,7 ;beeper off
call pit ;variable pitch
decfsz temp1,same ;delay sweep
goto siren13 ;
movlw 2 ;reset delayed sweep
movwf temp1 ;
btfsc _flags,0 ;test if up or down sweep
goto m13 ;
goto m14 ;
m13 decfsz temp2,same ;sweep timer
goto var13 ;
goto tog14 ;toggle if sweep over
m14 movlw 5 ;
subwf temp2,same ;
movf temp2,w ;
btfsc _status,_zero ;
goto var13 ;
goto tog14 ;toggle if sweep over
;--------------------------------------------------------------------------
tog14 btfsc _flags,0 ;test if sweep off
goto down14 ;pitch down
goto up14 ;pitch up
down14 bcf _flags,0 ;
goto siren13 ;
up14 bsf _flags,0 ;
goto siren13 ;
;---------------------------------------------------------------------------
var13 btfsc _flags,0 ;test if sweep up or down
goto re14 ;
decf temp3,same ;
goto siren13 ;
re14 movlw 255 ;
subwf temp3,w ;
btfsc _status,_carry ;set is positive
bcf _flags,0 ;
incf temp3,same ;
goto siren13 ;
;--------------------------------------------------------------------------
;----------------------------------------------------------------------------
;----------------------------------------------------------------------------
op12 bsf _flags,0 ;continues pulsed
movlw 40 ;
movwf temp3 ;pitch preset to 25
movlw 255 ;pulse timer
movwf temp5 ;
siren14 bsf port_b,7 ;beeper on
call pit ;variable pitch
bcf port_b,7 ;beeper off
call pit ;variable pitch
decfsz temp5,same ;
goto siren14 ;
qw3 clrwdt ;kick dog
call pit ;
decfsz temp5,same ;
goto qw3 ;
decfsz temp3 ;
goto qw3 ;
goto op12 ;
;--------------------------------------------------------------------------
;--------------------------------------------------------------------------
;--------------------------------------------------------------------------
op13 bsf _flags,0 ;double sweep fast
movlw 200 ;
movwf temp3 ;pitch preset to 25
siren15 bsf port_b,7 ;beeper on
call pit ;variable pitch
bcf port_b,7 ;beeper off
call pit ;variable pitch
decfsz temp3,same ;
goto siren15 ;
movlw 200 ;
movwf temp3 ;
goto siren15 ;
;---------------------------------------------------------------------------
;---------------------------------------------------------------------------
;---------------------------------------------------------------------------
op14 bsf _flags,0 ;
movlw 10 ;
movwf temp3 ;pitch preset to 25
siren16 bsf port_b,7 ;beeper on
call pit ;variable pitch
bcf port_b,7 ;beeper off
call pit ;variable pitch
movlw 1 ;
addwf temp3,same ;
goto siren16 ;
;----------------------------------------------------------------------------
org 3ffh ;
goto init ;
END ;
For 16F84 there’s an excuse for that, but wouldn’t it be easier for 16F628 to use hardware PWM
and have your software just adjust the registers?
I don’t see any benefit worrying about assembler for that.