;-------------------------------------------------------------------------;
; Darkroom Timer ;
; April '99 Stan Ockers (ockers@anl.gov) ;
; circuit diagram in CNTDN.PCX ;
; further description in CNTDN.TXT ;
; ;
; Counts down from 0-99 min and 0-59 sec giving an alarm at 0 ;
; initial counts are held in data EEPROM setable with one button ;
; ;
; RBO-RB3 to bases of transistors connect to common cathode of displays. ;
; RA0-RA3 to 1,2,4,8 BCD inputs of CD4511 7 segment latch and driver. ;
; RB7 to start pushbutton used to start countdown and silence alarm. ;
; RB6 goes to time set pushbutton use to sucessively set the digits. ;
; RA4 with pull-up resistor goes to PB to select from 15 starting counts ;
; RB4 and RB5 go to speaker which gives an alarm. ;
;-------------------------------------------------------------------------;
LIST P=16F84
#INCLUDE "p16f84.inc"
;-------------------------------------------------------------------------;
; Here we define our own personal registers and give them names ;
;-------------------------------------------------------------------------;
SEC EQU H'0C' ; this register holds the value of seconds
SEC10 EQU H'0D' ; holds value of 10's of seconds
MIN EQU H'0E' ; holds value of minutes
MIN10 EQU H'0F' ; holds value of 10's of minutes
DIGCTR EQU H'10' ; 8 bit counter, only 2 lowest bits actually used
DIGIT EQU H'11' ; hold digit number to access table
INTCNT EQU H'12' ; counts # interrupts to determine when 1 sec up
FUDGE EQU H'13' ; allows slight adjustment every 7 interrupts
RUNFLG EQU H'14' ; bit 0 only, tells if countdown in progress
W_TEMP EQU H'15' ; temporarily holds value of W
STATUS_TEMP EQU H'16' ; temporarily holds value of STATUS
SECNT EQU H'17' ; used in counting 50, 20 msec delays for 1 sec
CNTMSEC EQU H'18' ; used in timing of milliseconds
ALARM EQU H'19' ; bit 0 only, used as flag for when to alarm
OFFSET EQU H'1A' ; hold offset of address in EEPROM
;-------------------------------------------------------------------------;
; Here we give names to some numbers to make their use more clear ;
;-------------------------------------------------------------------------;
#DEFINE START_PB D'7'
#DEFINE SET_PB D'6'
#DEFINE SELECT_PB D'4'
#DEFINE RB4 D'4'
#DEFINE RB5 D'5'
;-------------------------------------------------------------------------;
; We set the start of code to orginate a location zero ;
;-------------------------------------------------------------------------;
ORG 0
GOTO MAIN ; jump to the main routine
NOP
NOP
NOP
GOTO INTERRUPT ; interrupt routine
;-------------------------------------------------------------------------;
; This table is used to get a bit pattern that will turn on a digit ;
;-------------------------------------------------------------------------;
BITPAT ADDWF PCL,f ; get bit pattern for transistors
RETLW H'0E' ; a low, (0), turns the transistor on
RETLW H'0D'
RETLW H'0B'
RETLW H'07'
;-------------------------------------------------------------------------;
; Initialization routine sets up ports and timer ;
;-------------------------------------------------------------------------;
INIT MOVLW H'C0' ; PB6 & PB7 inputs all others outputs
TRIS PORTB
MOVLW H'10' ; Port RA4 input, others outputs
TRIS PORTA
MOVLW H'03' ; prescaler on TMR0 and 1:16
OPTION
MOVLW H'A0' ; GIE & T0IE set T0IF cleared
MOVWF INTCON
MOVLW H'F4' ; initialize INTCNT
MOVWF INTCNT
MOVLW H'06' ; initialize FUDGE
MOVWF FUDGE
CLRF OFFSET ; initialize OFFSET
RETURN
;-------------------------------------------------------------------------;
; This is the interrupt routine that is jumped to when TMR0 overflows ;
;-------------------------------------------------------------------------;
INTERRUPT MOVWF W_TEMP ; save W
SWAPF STATUS,W ; save status
MOVWF STATUS_TEMP ; without changing flags
INCF DIGCTR,f ; next digit #
MOVF DIGCTR,W ; get it into W
ANDLW H'03' ; mask off 2 lowest bits
MOVWF DIGIT ; save it for later
ADDLW H'0C' ; point at register to display
MOVWF FSR ; use as pointer
MOVF INDF,W ; get value of reg pointed to into W
MOVWF PORTA ; output to CD4511
MOVF DIGIT,W ; recall digit #
CALL BITPAT ; get bit pattern
MOVWF PORTB ; select transistor
DECFSZ INTCNT,f ; finished 1 sec ?
GOTO RESTORE ; not yet, return and enable inter.
CALL EVERYSEC ; go to every second routine
MOVLW H'F4' ; reset INTCNT to normal value
MOVWF INTCNT
DECFSZ FUDGE,f ; time for fudge?
GOTO RESTORE ; not yet, continue on
MOVLW H'06' ; reset FUDGE to 6
MOVWF FUDGE
INCF INTCNT,f ; INTCNT to 245
RESTORE SWAPF STATUS_TEMP,W ; get original status back
MOVWF STATUS ; into status register
SWAPF STATUS_TEMP,f ; old no flags trick again
SWAPF STATUS_TEMP,W ; to restore W
BCF INTCON,T0IF ; clear the TMR0 interrupt flag
RETFIE ; finished
;-------------------------------------------------------------------------;
; This routine is called by the interrupt routine every second ;
;-------------------------------------------------------------------------;
EVERYSEC BTFSS RUNFLG,0 ; return if runflg not set
RETURN
DECF SEC,f ; decrement seconds digit
INCFSZ SEC,W ; test for underflow
GOTO CKZERO
MOVLW H'09' ; reset sec to 9
MOVWF SEC
DECF SEC10,f ; decrement SEC10
INCFSZ SEC10,W ; check underflow
GOTO CKZERO
MOVLW H'05'
MOVWF SEC10
DECF MIN,f
INCFSZ MIN,W
GOTO CKZERO
MOVLW H'09'
MOVWF MIN
DECF MIN10,f
CKZERO MOVF SEC,f ; test SEC for zero
BTFSS STATUS,Z
RETURN
MOVF SEC10,f ; check SEC10 for zero
BTFSS STATUS,Z
RETURN
MOVF MIN,f ; check MIN for zero
BTFSS STATUS,Z
RETURN
MOVF MIN10,f ; check MIN10 for zero
BTFSS STATUS,Z
RETURN
CLRF RUNFLG ; stop the countdown
BSF ALARM, 0 ; set the alarm flag
RETURN
;-------------------------------------------------------------------------;
; This is a routine to read a byte from the data EEPROM ;
;-------------------------------------------------------------------------;
READEE MOVWF EEADR ; set up eeprom address from W
BSF STATUS,RP0 ; change to page 1
BSF EECON1,RD ; set the read bit
BCF STATUS,RP0 ; back to page 0
MOVF EEDATA,W ; return value in W
RETURN
;-------------------------------------------------------------------------;
; This routine fills the display registers from data EEPROM ;
;-------------------------------------------------------------------------;
GETEE MOVLW H'01' ; EEprom location 1 +
ADDWF OFFSET,W ; offset from start
CALL READEE ; into W
MOVWF SEC ; into SEC register
MOVLW H'02' ; location 2 +
ADDWF OFFSET,W ; offset from start
CALL READEE ; into W
MOVWF SEC10 ; into SEC10 register
MOVLW H'03' ; location 3 +
ADDWF OFFSET,W ; offset from start
CALL READEE ; into W
MOVWF MIN ; into MIN register
MOVLW H'04' ; location 4 +
ADDWF OFFSET,W ; offset from start
CALL READEE ; into W
MOVWF MIN10 ; into MIN10 register
RETURN
;-------------------------------------------------------------------------;
; This routine writes a byte to data EEPROM ;
;-------------------------------------------------------------------------;
WRITEEE BSF STATUS,RP0 ; set up EEADR and EEDATA first
CLRF EECON1
BSF EECON1,WREN ; enable write
MOVLW H'55' ; magic sequence
MOVWF EECON2
MOVLW H'AA'
MOVWF EECON2
BSF EECON1,WR
EELOOP BTFSC EECON1,WR ; wait for WR to go low
GOTO EELOOP ; not yet
BSF EECON1,WREN
BCF EECON1,EEIF ; clear the interrupt flag
BCF STATUS,RP0 ; return to page 0
RETURN
;-------------------------------------------------------------------------;
; This routine puts display registers into data EEPROM ;
;-------------------------------------------------------------------------;
PUTEE MOVF SEC,W ; put digit registers into EEprom
MOVWF EEDATA
MOVLW H'01' ; EEPROM location 1 +
ADDWF OFFSET,W ; offset from start
MOVWF EEADR
CALL WRITEEE
MOVF SEC10,W
MOVWF EEDATA
MOVLW H'02' ; EEPROM location 2 +
ADDWF OFFSET,W ; offset from start
MOVWF EEADR
CALL WRITEEE
MOVF MIN,W
MOVWF EEDATA
MOVLW H'03' ; EEPROM location 3 +
ADDWF OFFSET,W ; offset from start
MOVWF EEADR
CALL WRITEEE
MOVF MIN10,W
MOVWF EEDATA
MOVLW H'04' ; EEPROM location 4 +
ADDWF OFFSET,W ; offset from start
MOVWF EEADR
CALL WRITEEE
RETURN
;-------------------------------------------------------------------------;
; This is the main routine, the program starts here ;
;-------------------------------------------------------------------------;
MAIN CALL INIT ; set up ports etc.
;-------------------------------------------------------------------------;
; We will return to this point when alarm is shut off. ;
;-------------------------------------------------------------------------;
EE2D CALL GETEE ; put eeprom in display regs.
BCF RUNFLG, 0 ; clear run flag so no countdown
BCF ALARM, 0 ; clear alarm flag
CALL WAITSTARTUP ; wait till no switches pressed
CALL WAITSETUP
CALL WAITSELECT
;-------------------------------------------------------------------------;
; This loop checks for either pushbutton and acts accordingly ;
;-------------------------------------------------------------------------;
KEYCHKLOOP BTFSS PORTB,START_PB ; check for start pressed
GOTO STARTCNT ; yes, start count
BTFSS PORTB,SET_PB ; check for set pressed
GOTO SETDISP ; yes, set display
BTFSS PORTA,SELECT_PB ; check select pushbutton pressed
GOTO SETSELECT ; yes, select starting count
GOTO KEYCHKLOOP ; loop to catch key press
;-------------------------------------------------------------------------;
; If start key has been pressed then start countdown process, ;
; I initially released this code with only the setting of the ;
; run flag included. If you think about it you must also reset ;
; TMR0 to zero. TMR0 is free running and could have any value ;
; 0-255 when the button in pressed. Also INTCNT has to be ;
; initialized because the previous count could have been cancelled. ;
;-------------------------------------------------------------------------;
STARTCNT CALL WAITSTARTUP ; wait for release of start key
MOVLW D'244' ; reset INTCNT
MOVWF INTCNT
CLRF TMR0 ; and clear timer 0
BSF RUNFLG, 0 ; start the countdown
;-------------------------------------------------------------------------;
; Once started just loop looking for cancel or reaching 0000 ;
;-------------------------------------------------------------------------;
MAINLOOP BTFSS PORTB,START_PB ; countdown in progress, check start
GOTO EE2D ; start over again if pressed
BTFSC ALARM, 0 ; reached 0000 yet?
GOTO SOUNDALARM ; yes, turn alarm on
GOTO MAINLOOP ; no start switch, continue looping
;-------------------------------------------------------------------------;
; This code sounds the alarm and waits on start to be pressed ;
;-------------------------------------------------------------------------;
SOUNDALARM
FINALWAIT BCF PORTB,RB4 ; speaker leads set up
BSF PORTB,RB5 ; opposite polarity
MOVLW 2 ; delay 2 milliseconds
CALL NMSEC
BSF PORTB,RB4 ; flip the speaker leads
BCF PORTB,RB5
MOVLW 2 ; another 2 msec delay
CALL NMSEC
BTFSC PORTB,START_PB ; start button pressed
GOTO FINALWAIT ; not yet
CALL DLY20 ; debounce just to make sure
BTFSC PORTB,START_PB ; second look
GOTO FINALWAIT ; nah, keep waiting
BCF PORTB,RB4 ; speaker leads set to same polarity
BCF PORTB,RB5
CALL WAITSTARTUP ; now wait for the switch up
GOTO EE2D ; start all over again
;-------------------------------------------------------------------------;
; Wait for release of start button ;
;-------------------------------------------------------------------------;
WAITSTARTUP BTFSS PORTB,START_PB ; wait for release
GOTO WAITSTARTUP ; not released yet
CALL DLY20 ; debounce release
BTFSS PORTB,START_PB ; 2nd check, make sure released
GOTO WAITSTARTUP ; keep checking
RETURN
;-------------------------------------------------------------------------;
; Wait for release of set button ;
;-------------------------------------------------------------------------;
WAITSETUP BTFSS PORTB,SET_PB ; wait for release
GOTO WAITSETUP ; not yet
CALL DLY20 ; debounce release
BTFSS PORTB,SET_PB ; 2nd check, make sure released
GOTO WAITSETUP ; keep checking
RETURN
;-------------------------------------------------------------------------;
; Wait for release of select button ;
;-------------------------------------------------------------------------;
WAITSELECT BTFSS PORTA,SELECT_PB ; wait for release
GOTO WAITSELECT ; not yet
CALL DLY20 ; debounce release
BTFSS PORTA,SELECT_PB ; 2nd check, make sure released
GOTO WAITSELECT ; keep checking
RETURN
;-------------------------------------------------------------------------;
; Routine to follow sets the countdown time digit by digit ;
;-------------------------------------------------------------------------;
SETDISP CALL WAITSETUP ; wait for set key to be released
MOVLW H'0A' ; put A's in digits, (no display)
MOVWF MIN10 ; 10's of minutes
MOVWF MIN ; minutes
MOVWF SEC10 ; 10's of seconds
MOVWF SEC ; seconds
STARTMIN10 CLRF MIN10 ; 0 now in MIN10
MOREMIN10 MOVLW H'32' ; 50 delays of 20 msec
MOVWF SECNT ; into counting register
WAIT1 CALL DLY20
BTFSS PORTB,SET_PB ; set key pressed?
GOTO MINSET ; yes MIN10 now set
DECFSZ SECNT,f ; finished 1 sec delay?
GOTO WAIT1 ; continue wait
INCF MIN10,f ; every second increment 10's MIN
MOVLW H'0A' ; reached 10?
SUBWF MIN10,W
BTFSC STATUS,Z ; Z set if reached 10
GOTO STARTMIN10 ; start again with 0
GOTO MOREMIN10 ; set up another 1 sec delay
MINSET CALL WAITSETUP ; wait for release of set key
STARTMIN CLRF MIN ; 0 into MIN
MOREMIN MOVLW H'32' ; 50 delays of 20 msec
MOVWF SECNT ; into counting register
WAIT2 CALL DLY20
BTFSS PORTB,SET_PB ; set pressed?
GOTO SETSEC10 ; yes, finished with MIN
DECFSZ SECNT,f ; finished 1 sec delay?
GOTO WAIT2 ; continue wait
INCF MIN,f ; every second increment MIN
MOVLW H'0A' ; reached 10?
SUBWF MIN,W
BTFSC STATUS,Z ; Z set if reached 10
GOTO STARTMIN ; put zero in if Z set
GOTO MOREMIN ; set up another 1 sec delay
SETSEC10 CALL WAITSETUP ; wait release
STARTSEC10 CLRF SEC10 ; 0 into SEC10
MORESEC10 MOVLW H'32' ; 50 delays of 20 msec
MOVWF SECNT ; into counting register
WAIT3 CALL DLY20
BTFSS PORTB,SET_PB ; set pressed?
GOTO SETSEC ; yes quit incrementing
DECFSZ SECNT,f ; finished 1 sec delay?
GOTO WAIT3 ; continue wait
INCF SEC10,f ; every second increment 10's SEC
MOVLW H'06' ; reached 6?
SUBWF SEC10,W
BTFSC STATUS,Z ; Z set if reached 6
GOTO STARTSEC10 ; put zero in if Z set
GOTO MORESEC10 ; set up another 1 sec delay
SETSEC CALL WAITSETUP ; wait for release
STARTSEC CLRF SEC ; 0 into SEC
MORESEC MOVLW H'32' ; 50 delays of 20 msec
MOVWF SECNT ; into counting register
WAIT4 CALL DLY20
BTFSS PORTB,SET_PB ; set button pressed?
GOTO FINSET ; yes finished setting digits
DECFSZ SECNT,f ; finished 1 sec delay?
GOTO WAIT4 ; continue wait
INCF SEC,f ; every second increment SEC
MOVLW H'0A' ; reached 10?
SUBWF SEC,W
BTFSC STATUS,Z ; Z set if reached 10
GOTO STARTSEC ; put zero in if Z set
GOTO MORESEC ; set up another 1 sec delay
FINSET BCF INTCON, GIE ; disable interrupts
CALL PUTEE ; put new digits into EEPROM
BSF INTCON, GIE ; re-enable interrupts
CALL WAITSETUP ; make sure set switch up
GOTO KEYCHKLOOP ; start checking buttons again
;-------------------------------------------------------------------------;
; Selects starting count by changing EEPROM location 0 ;
;-------------------------------------------------------------------------;
SETSELECT MOVLW D'4' ; offset up 4
ADDWF OFFSET,F ; next offset position
MOVLW D'60' ; reached 16th yet?
SUBWF OFFSET,W ; will give zero if yes
BTFSC STATUS,Z ; skip if not 64
CLRF OFFSET ; reset position to zero
MOVLW 0 ; EEPROM location
MOVWF EEADR ; set up address
MOVF OFFSET,W ; offset # into W
MOVWF EEDATA ; set up data
BCF INTCON,GIE ; clear GIE, disable interrupts
CALL WRITEEE ; save # in location 0
BSF INTCON,GIE ; re-enable interrupts
CALL GETEE ; get new start count into display
CALL WAITSELECT ; make sure select switch is up
GOTO KEYCHKLOOP ; start checking buttons again
;-------------------------------------------------------------------------;
; The following are various delay routines based on instruction length. ;
; The instruction length is assumed to be 1 microsecond (4Mhz crystal). ;
;-------------------------------------------------------------------------;
DLY20 MOVLW 20 ; delay for 20 milliseconds
;*** N millisecond delay routine ***
NMSEC MOVWF CNTMSEC ; delay for N (in W) milliseconds
MSECLOOP MOVLW D'248' ; load takes 1 microsec
CALL MICRO4 ; by itself CALL takes ...
; 2 + 247 X 4 + 3 + 2 = 995
NOP ; 1 more microsec
DECFSZ CNTMSEC,f ; 1 when skip not taken, else 2
GOTO MSECLOOP ; 2 here: total 1000 per msecloop
RETURN ; final time through takes 999 to here
; overhead in and out ignored
;*** 1 millisecond delay routine ***
ONEMSEC MOVLW D'249' ; 1 microsec for load W
; loops below take 248 X 4 + 3 = 995
MICRO4 ADDLW H'FF' ; subtract 1 from 'W'
BTFSS STATUS,Z ; skip when you reach zero
GOTO MICRO4 ; loops takes 4 microsec, 3 for last
RETURN ; takes 2 microsec
; call + load W + loops + return =
; 2 + 1 + 995 + 2 = 1000 microsec
;-------------------------------------------------------------------------;
; Here we set up the initial values of the digits in data EEPROM ;
;-------------------------------------------------------------------------;
ORG H'2100'
DE 0, 1, 0, 0, 0 ; 1st starting #
DE 2, 0, 0, 0 ; 2nd starting #
DE 3, 0, 0, 0 ; 3rd starting #
DE 4, 0, 0, 0 ; 4th starting #
DE 5, 0, 0, 0 ; 5th starting #
DE 6, 0, 0, 0 ; 6th starting #
DE 7, 0, 0, 0 ; 7th starting #
DE 8, 0, 0, 0 ; 8th starting #
DE 9, 0, 0, 0 ; 9th starting #
DE 0, 1, 0, 0 ; 10th starting #
DE 1, 1, 0, 0 ; 11th starting #
DE 2, 1, 0, 0 ; 12th starting #
DE 3, 1, 0, 0 ; 13th starting #
DE 4, 1, 0, 0 ; 14th starting #
DE 5, 1, 0, 0 ; 15th starting #
END
<P>See:
<UL>
<LI>
</UL>
<P>
</BODY></HTML>
| file: /Techref/microchip/cntdn/cntdn.asm, 26KB, , updated: 2013/9/8 03:28, local time: 2024/11/15 01:26,
18.217.32.71:LOG IN
|
| ©2024 These pages are served without commercial sponsorship. (No popup ads, etc...).Bandwidth abuse increases hosting cost forcing sponsorship or shutdown. This server aggressively defends against automated copying for any reason including offline viewing, duplication, etc... Please respect this requirement and DO NOT RIP THIS SITE. Questions? <A HREF="http://massmind.ecomorder.com/Techref/microchip/cntdn/cntdn.asm"> microchip cntdn cntdn</A> |
| Did you find what you needed? |
Welcome to ecomorder.com! |
Welcome to massmind.ecomorder.com! |
.