;******************************************************************************
; FREQUENCY COUNTER
; Model : WTCNT
; Author : Terry J. Weeder
; Date : November 18, 1993
; Version: 1.0
;
; WWW.WEEDTECH.COM
;
; Ported to 16f84 by
; Peter Cousens
; October 1998
;
; lines 337 to 453 are an example of where to add personal introductory
; lines and should be omitted or changed to your own
;******************************************************************************
;
;watchdog disabled
;
list P=16F84
ind equ 0h
rtcc equ 1h
pc equ 2h
status equ 3h
fsr equ 4h
port_a equ 5h
port_b equ 6h
;port_c equ 7h
c equ 0h
dc equ 1h
z equ 2h
pd equ 3h
to equ 4h
MSB equ 7h
LSB equ 0h
;
cnt equ 2h
rs equ 2h
rw equ 1h
e equ 0h
o equ 7h
;
count1 equ 2ah
count2 equ 2bh
count3 equ 2ch
count4 equ 2dh
in_reg equ 2eh
addcnt equ 2fh
gate equ 0Ch
cnt1 equ 0Dh
cnt2 equ 0Eh
cnt3 equ 0Fh
calc1 equ 10h
calc2 equ 11h
calc3 equ 12h
sum1 equ 13h
sum2 equ 14h
sum3 equ 15h
rtcc2 equ 16h
;
org 0
goto start
;
int_del movlw 0x05 ;delay 5.000 ms (4 MHz clock)
movwf count1
d1 movlw 0xA5
movwf count2
d2 decfsz count2 ,f
goto d2
decfsz count1 ,f
goto d1
retlw 0x00
;
lcd_out movwf port_b ;load data into port_b
movlw b'00000000' ;define port_b as output
tris port_b
bsf port_a,rs ;rs = data
bcf port_a,rw ;r/w = write
bsf port_a,e ;toggle enable
bcf port_a,e
movlw b'11111111' ;define port_b as input
tris port_b
bcf port_a,rs ;rs = instruction
bsf port_a,rw ;r/w = read
bsf port_a,e ;enable high
movf port_b,w ;get address counter
movwf addcnt
bsf addcnt,7
bcf port_a,e ;enable low
out1 bsf port_a,e ;enable high
btfss port_b,7 ;test busy flag
goto out2
bcf port_a,e ;enable low
goto out1
out2 bcf port_a,e ;enable low
goto shift
;
inst movwf port_b ;load instruction into port_b
movlw b'00000000' ;define port_b as output
tris port_b
bcf port_a,rs ;rs = instruction
bcf port_a,rw ;r/w = write
bsf port_a,e ;toggle enable
bcf port_a,e
movlw b'11111111' ;define port_b as input
tris port_b
bsf port_a,rw ;r/w = read
inst1 bsf port_a,e ;enable high
btfss port_b,7 ;test busy flag
goto inst2
bcf port_a,e ;enable low
goto inst1
inst2 bcf port_a,e ;enable low
retlw 0x00
;
shift btfss addcnt,0 ;shift to opposite side of display?
retlw 0x00
btfss addcnt,1
retlw 0x00
btfss addcnt,2
retlw 0x00
btfss addcnt,3
retlw 0x00
movlw 0x39
addwf addcnt,f
bsf addcnt,7
movf addcnt,w
goto inst
;
sub bcf status,o ;clear overflow bit
movf calc1,w ;subtract calc1 from cnt1
subwf cnt1 ,f
btfsc status,c
goto sb1
movlw 0x01 ;borrow from cnt2 if overflow
subwf cnt2 ,f
btfsc status,c
goto sb1
subwf cnt3 ,f ;borrow from cnt3 if cnt2 overflow
btfss status,c
bsf status,o ;set overflow bit if result is negative
sb1 movf calc2,w ;subtract calc2 from cnt2
subwf cnt2 ,f
btfsc status,c
goto sb2
movlw 0x01 ;borrow from cnt3 if cnt2 overflow
subwf cnt3 ,f
btfss status,c
bsf status,o ;set overflow bit if result is negative
sb2 movf calc3,w ;subtract calc3 from cnt3
subwf cnt3 ,f
btfss status,c
bsf status,o ;set overflow bit if result is negative
retlw 0x00
;
add movf calc1,w ;add calc1 to cnt1
addwf cnt1 ,f
btfss status,c
goto ad1
incfsz cnt2 ,f ;add to cnt2 if cnt1 overflow
goto ad1
incf cnt3 ,f ;add to cnt3 if cnt2 overflow
ad1 movf calc2,w ;add calc2 to cnt2
addwf cnt2 ,f
btfsc status,c
incf cnt3 ,f ;add to cnt3 if cnt2 overflow
movf calc3,w ;add calc3 to cnt3
addwf cnt3 ,f
retlw 0x00
;
cnvt movlw 0x07 ;7 digits in display
movwf count1
movlw 0x19 ;set fsr for MSB in display
movwf fsr
movlw 0x2F ;one less that ASCII "0"
cnvt0 movwf ind
incf fsr ,f
decfsz count1 ,f
goto cnvt0
movlw 0x0F ;load "1,000,000" in calc1-3
movwf calc3
movlw 0x42
movwf calc2
movlw 0x40
movwf calc1
cnvt1 call sub ;subtract number from count
incf 19 ,f ;increment 1,000,000's register
movlw 0x3A
xorwf 19,w
btfsc status,z
goto overflow
btfss status,o ;check if overflow
goto cnvt1
call add ;add back last number
movlw 0x01 ;load "100,000" in calc1-3
movwf calc3
movlw 0x86
movwf calc2
movlw 0xA0
movwf calc1
cnvt2 call sub ;subtract number from count
incf 1A ,f ;increment 100,000's register
btfss status,o ;check if overflow
goto cnvt2
call add ;add back last number
clrf calc3 ;load "10,000" in calc1-3
movlw 0x27
movwf calc2
movlw 0x10
movwf calc1
cnvt3 call sub ;subtract number from count
incf 1B ,f ;increment 10,000's register
btfss status,o ;check if overflow
goto cnvt3
call add ;add back last number
movlw 0x03 ;load "1,000" in calc1-3
movwf calc2
movlw 0xE8
movwf calc1
cnvt4 call sub ;subtract number from count
incf 1C ,f ;increment 1,000's register
btfss status,o ;check if overflow
goto cnvt4
call add ;add back last number
clrf calc2 ;load "100" in calc1-3
movlw 0x64
movwf calc1
cnvt5 call sub ;subtract number from count
incf 1D ,f ;increment 100's register
btfss status,o ;check if overflow
goto cnvt5
call add ;add back number
movlw 0x0A ;load "10" in calc1-3
movwf calc1
cnvt6 call sub ;subtract number from count
incf 1E ,f ;increment 10's register
btfss status,o ;check if overflow
goto cnvt6
call add ;add back last number
movf cnt1,w ;put remainder in 1's register
addwf 1F ,f
incf 1F ,f
retlw 0x00
;
count movlw b'00110111' ;rtcc = ext, 1/256
option
movlw b'00010000' ;define port_a as output
tris port_a
bcf port_a,3
bcf port_a,2
clrf cnt3
clrf rtcc
clrf rtcc2
bsf port_a,2 ;toggle rtcc pin
bcf port_a,2
movf gate,w ;get gate time
movwf count1
bsf port_a,3 ;start count
fr4 movlw 0xFA
movwf count2
goto fr6
fr5 nop
nop
nop
nop
nop
nop
fr6 movf rtcc,w ;test for rtcc rollover (12)
subwf rtcc2 ,f
btfss status,z
goto fr7
nop
goto fr8
fr7 btfsc status,c
incf cnt3 ,f
fr8 movwf rtcc2
nop
nop
nop
decfsz count2 ,f
goto fr5
decfsz count1 ,f
goto fr4
bcf port_a,3 ;stop count
movf rtcc,w ;get rtcc count
movwf cnt2
subwf rtcc2 ,f ;test for rtcc rollover
btfss status,c
goto fr9
btfss status,z
incf cnt3 ,f
fr9 clrf cnt1 ;set to get prescaler count
fr10 decf cnt1 ,f
bsf port_a,2 ;toggle rtcc pin
bcf port_a,2
movf rtcc,w ;test if rtcc has changed
xorwf cnt2,w
btfsc status,z
goto fr10
retlw 0x00
;
;******************************************************************************
; START
;******************************************************************************
;
start clrf port_a ;instruction, write, enable low
movlw b'00010000'
tris port_a
clrf port_b
movlw b'00000000'
tris port_b
call int_del
call int_del
call int_del
movlw 0x38 ;initialize display
movwf port_b
bsf port_a,e ;toggle enable
call int_del
bcf port_a,e
bsf port_a,e ;toggle enable
call int_del
bcf port_a,e
bsf port_a,e ;toggle enable
call int_del
bcf port_a,e
bcf port_b,4 ;function
call inst
movlw b'00001100' ;display on, cursor off
call inst
movlw b'00000001' ;clear display
call inst
movlw b'00000110' ;entry mode
call inst
; new lines here for intro
movlw 0x20 ;space
call lcd_out
movlw 0x20 ;space
call lcd_out
movlw 0x50 ;P
call lcd_out
movlw 0x65 ;e
call lcd_out
movlw 0x74 ;t
call lcd_out
movlw 0x65 ;e
call lcd_out
movlw 0x72 ;r
call lcd_out
movlw 0x20 ;space
call lcd_out
movlw 0x43 ;C
call lcd_out
movlw 0x6f ;o
call lcd_out
movlw 0x75 ;u
call lcd_out
movlw 0x73 ;s
call lcd_out
movlw 0x65 ;e
call lcd_out
movlw 0x6e ;n
call lcd_out
movlw 0x73 ;s
call lcd_out
movlw 0x06 ;change the 6 to a smaller No. to speed up the intro
movwf count3
wait1 movlw 0xc8
movwf count4
wait2 call int_del
decfsz count4 ,f
goto wait2
decfsz count3 ,f
goto wait1
movlw b'00000001' ;clear display
call inst
movlw b'00000110' ;entry mode
call inst
movlw 0x20 ;space
call lcd_out
movlw 0x20 ;space
call lcd_out
movlw 0x47 ;G
call lcd_out
movlw 0x65 ;e
call lcd_out
movlw 0x6e ;n
call lcd_out
movlw 0x69 ;i
call lcd_out
movlw 0x75 ;u
call lcd_out
movlw 0x73 ;s
call lcd_out
movlw 0x20 ;space
call lcd_out
movlw 0x26 ;&
call lcd_out
movlw 0x20 ;space
call lcd_out
movlw 0x47 ;G
call lcd_out
movlw 0x6f ;o
call lcd_out
movlw 0x64 ;d
call lcd_out
movlw 0x20 ;space
call lcd_out
movlw 0x06
movwf count3
wait3 movlw 0xc8
movwf count4
wait4 call int_del
decfsz count4 ,f
goto wait4
decfsz count3 ,f
goto wait3
movlw b'00000001' ;clear display
call inst
movlw b'00000110' ;entry mode
call inst
movlw 0x20 ;space
call lcd_out
movlw 0x20 ;space
call lcd_out
movlw 0x57 ;W
call lcd_out
movlw 0x6f ;o
call lcd_out
movlw 0x75 ;u
call lcd_out
movlw 0x6c ;l
call lcd_out
movlw 0x64 ;d
call lcd_out
movlw 0x20 ;space
call lcd_out
movlw 0x49 ;I
call lcd_out
movlw 0x20 ;space
call lcd_out
movlw 0x4c ;L
call lcd_out
movlw 0x69 ;i
call lcd_out
movlw 0x65 ;e
call lcd_out
movlw 0x20 ;space
call lcd_out
movlw 0x3f ;?
call lcd_out
movlw 0x20 ;space
call lcd_out
movlw 0x06
movwf count3
wait5 movlw 0xc8
movwf count4
wait6 call int_del
decfsz count4 ,f
goto wait6
decfsz count3 ,f
goto wait5
movlw b'00000001' ;clear display
call inst
movlw b'00000110' ;entry mode
call inst
;
mhz movlw 0x14 ;0.1 sec gate
movwf gate
call count
call cnvt ;convert binary to BCD
movlw 0x30 ;test if "0"
xorwf 19,w
btfss status,z
goto mhz1
movlw 0x30 ;test if "0"
xorwf 1A,w
btfsc status,z
goto khz1
mhz1 movlw 0x82 ;set display address
call inst
movlw 0x02 ;output first 2 characters
movwf count1
movlw 0x19 ;MSD of freq
movwf fsr
mhz2 movlw 0x30 ;test if "0"
xorwf ind,w
btfss status,z
goto mhz3
movlw 0x20 ;change preceeding "0's" to "space"
call lcd_out
incf fsr ,f
decfsz count1 ,f
goto mhz2
goto mhz4
mhz3 movf ind,w
call lcd_out
incf fsr ,f
decfsz count1 ,f
goto mhz3
mhz4 movlw 0x2E ;"."
call lcd_out
movlw 0x05 ;output last 5 characters
movwf count1
mhz5 movf ind,w
call lcd_out
incf fsr ,f
decfsz count1 ,f
goto mhz5
movlw 0x20 ;"space"
call lcd_out
movlw 0x4D ;"M"
call lcd_out
movlw 0x48 ;"H"
call lcd_out
movlw 0x7A ;"z"
call lcd_out
movlw 0x20 ;"space"
call lcd_out
movlw 0x20 ;"space"
call lcd_out
goto mhz
;
khz movlw 0x14 ;0.1 sec gate
movwf gate
call count
call cnvt ;convert binary to BCD
movlw 0x30 ;test if 0
xorwf 19,w
btfss status,z
goto mhz1
movlw 0x32 ;test if < 2
subwf 1A,w
btfsc status,c
goto mhz1
movlw 0x30 ;test if "0"
xorwf 1A,w
btfss status,z
goto khz1
movlw 0x30 ;test if "0"
xorwf 1B,w
btfsc status,z
goto xkhz
khz1 movlw 0x82 ;set display address
call inst
movlw 0x05 ;output first 5 characters
movwf count1
movlw 0x19 ;MSD of freq
movwf fsr
khz2 movlw 0x30 ;test if "0"
xorwf ind,w
btfss status,z
goto khz3
movlw 0x20 ;change preceeding "0's" to "space"
call lcd_out
incf fsr ,f
decfsz count1 ,f
goto khz2
goto khz4
khz3 movf ind,w
call lcd_out
incf fsr ,f
decfsz count1 ,f
goto khz3
khz4 movlw 0x2E ;"."
call lcd_out
movf ind,w ;output last 2 characters
call lcd_out
incf fsr ,f
movf ind,w
call lcd_out
movlw 0x20 ;"space"
call lcd_out
movlw 0x4B ;"K"
call lcd_out
movlw 0x48 ;"H"
call lcd_out
movlw 0x7A ;"z"
call lcd_out
movlw 0x20 ;"space"
call lcd_out
movlw 0x20 ;"space"
call lcd_out
goto khz
;
xkhz movlw 0xC8 ;1 sec gate
movwf gate
call count
call cnvt ;convert binary to BCD
movlw 0x30 ;test if 0
xorwf 19,w
btfss status,z
goto khz
movlw 0x32 ;test if < 2
subwf 1A,w
btfsc status,c
goto khz
movlw 0x30 ;test if 0
xorwf 1A,w
btfss status,z
goto xkhz1
movlw 0x30 ;test if 0
xorwf 1B,w
btfsc status,z
goto hz0
xkhz1 movlw 0x82 ;set display address
call inst
movlw 0x04 ;output first 4 characters
movwf count1
movlw 0x19 ;MSD of freq
movwf fsr
xkhz2 movlw 0x30 ;test if "0"
xorwf ind,w
btfss status,z
goto xkhz3
movlw 0x20 ;change preceeding "0's" to "space"
call lcd_out
incf fsr ,f
decfsz count1 ,f
goto xkhz2
goto xkhz4
xkhz3 movf ind,w
call lcd_out
incf fsr ,f
decfsz count1 ,f
goto xkhz3
xkhz4 movlw 0x2E ;"."
call lcd_out
movf ind,w ;output last 3 characters
call lcd_out
incf fsr ,f
movf ind,w
call lcd_out
incf fsr ,f
movf ind,w
call lcd_out
movlw 0x20 ;"space"
call lcd_out
movlw 0x4B ;"K"
call lcd_out
movlw 0x48 ;"H"
call lcd_out
movlw 0x7A ;"z"
call lcd_out
movlw 0x20 ;"space"
call lcd_out
movlw 0x20 ;"space"
call lcd_out
goto xkhz
;
hz movlw 0xC8 ;1 sec gate
movwf gate
call count
call cnvt ;convert binary to BCD
movlw 0x30 ;test if "0"
xorwf 19,w
btfss status,z
goto xkhz1
movlw 0x30 ;test if "0"
xorwf 1A,w
btfss status,z
goto xkhz1
movlw 0x32 ;test if < 2
subwf 1B,w
btfsc status,c
goto xkhz1
hz0 movlw 0x82 ;set display address
call inst
movlw 0x07 ;output first 7 characters
movwf count1
movlw 0x19 ;MSD of freq
movwf fsr
hz1 movlw 0x30 ;test if "0"
xorwf ind,w
btfss status,z
goto hz2
movlw 0x20 ;change preceeding "0's" to "space"
call lcd_out
incf fsr ,f
decfsz count1 ,f
goto hz1
goto hz3
hz2 movf ind,w
call lcd_out
incf fsr ,f
decfsz count1 ,f
goto hz2
hz3 movlw 0x20 ;"space"
call lcd_out
movlw 0x48 ;"H"
call lcd_out
movlw 0x7A ;"z"
call lcd_out
movlw 0x20 ;"space"
call lcd_out
movlw 0x20 ;"space"
call lcd_out
movlw 0x20 ;"space"
call lcd_out
movlw 0x20 ;"space"
call lcd_out
goto hz
;
overflow movlw 0x01 ;clear display
call inst
movlw 0x84 ;display address
call inst
movlw 0x4F ;"O"
call lcd_out
movlw 0x76 ;"v"
call lcd_out
movlw 0x65 ;"e"
call lcd_out
movlw 0x72 ;"r"
call lcd_out
movlw 0x66 ;"f"
call lcd_out
movlw 0x6C ;"l"
call lcd_out
movlw 0x6F ;"o"
call lcd_out
movlw 0x77 ;"w"
call lcd_out
movlw 0x02 ;cursor at home
call inst
goto mhz
;
end
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