;----------------------------------------------------------------------; ; BINCLK4M.ASM A clock that displays in bcd numbers ; ;----------------------------------------------------------------------; ; .-----------. ; -|RA2 RA1|- V+ = 4.5 or 5 Volts ; -|RA3 RA0|- X = 4.096 MHz xtal ; -|RA4 OSC1|--|X|-||--- gnd 20 pf caps ; -{r}- = 470 ohm V+ ---|MCLR OSC2|--|X|-||--- gnd ; -|<- = LED gnd ---|Vss Vdd|--- V+ ; gnd ---|<--{r}--|RB0 RB7|- ; gnd ---|<--{r}--|RB1 RB6|- ; gnd ---|<--{r}--|RB2 RB5|---[PB]--- gnd <- SET PB ; gnd ---|<--{r}--|RB3 RB4|---[PB]--- gnd <- SHOW PB ; '-----------' ; PIC16F84 -[PB]- pushbutton LIST P=16F84 ; tells which processor is used INCLUDE "p16f84.inc" ; defines various registers etc. Look ERRORLEVEL -224 ; supress annoying message from tris __CONFIG _PWRTE_ON & _XT_OSC & _WDT_OFF ; config. switches CBLOCK 0CH sec ; seconds digit sec10 ; 10's of second digit mins ; minutes digit min10 ; 10's of minutes digit hr ; hours digit hr10 ; 10's of hours digit w_temp ; holds W during interrupt status_temp ; holds STATUS during interrupt fsr_temp ; holds FSR during interrupt digit ; holds digit position cntmsec ; used to count milliseconds counter ; used to stretch isr out to 1 sec flashcnt ; counter for flashing LED ENDC ;----------------------------------------------------------------------; ; Here are some DEFINEs which give 'names' to pushbutton port bits ; ;----------------------------------------------------------------------; #DEFINE SHOWPB PORTB, 4 #DEFINE SETPB PORTB, 5 ORG 0 ; start at location 0 goto main ; jump over to main routine ORG 4 goto isr ; jump to interrupt routine ;----------------------------------------------------------------------; ; High limit + 1 of digits at position W ; ;----------------------------------------------------------------------; sethi: addwf PCL, f dt H'A',H'6',H'A',H'6',H'A',H'3' ;----------------------------------------------------------------------; ; time delay routines ; ;----------------------------------------------------------------------; micro4 addlw H'FF' ; subtract 1 from 'W' btfss STATUS,Z ; skip when you reach zero goto micro4 ; more loops return msec250: movlw D'250' ; delay for 250 milliseconds ;*** N millisecond delay routine *** nmsec: movwf cntmsec ; delay for N (in W) millisec msecloop: movlw D'248' ; 1 usec for load call micro4 ; this instruction is 995 usec nop ; 1 usec decfsz cntmsec,f ; 1 usec, (2 if skip taken) goto msecloop ; 2 usec, loop = 995+5 = 1 msec return ;----------------------------------------------------------------------; ; Delay for one second ; ;----------------------------------------------------------------------; onesecond: ; a subroutine that delays for 1 seconds call msec250 call msec250 call msec250 call msec250 return ;----------------------------------------------------------------------; ; Put value in W on LEDs for 1 second ; ;----------------------------------------------------------------------; sendnbr: btfsc STATUS, Z ; skip if not zero movlw H'0F' ; else all on for a zero movwf PORTB ; light LEDs call onesecond ; wait 1 second clrf PORTB ; clear the LEDs movlw D'100' ; pause for 0.1 sec call nmsec return ;----------------------------------------------------------------------; ; Send the current time out LEDs ; ;----------------------------------------------------------------------; disptime: movf hr10, W call sendnbr movf hr, W call sendnbr movf min10, W call sendnbr movf mins, W call sendnbr return ;----------------------------------------------------------------------; ; Wait until set button is released ; ;----------------------------------------------------------------------; waitsetup: ; wait for set pushbutton up btfss SETPB ; skip if set button released goto waitsetup movlw D'10' call nmsec ; wait 10 msec for debounce btfss SETPB ; check again for release goto waitsetup ; false alarm, start over return ; yes, finished ;----------------------------------------------------------------------; ; Initialization Subroutine ; ;----------------------------------------------------------------------; init: movlw B'0000000' ; all outputs port A tris PORTA movlw B'00110000' ; RB4, RB5 inputs, others outputs tris PORTB ; on port B movlw H'0' ; all low (off) movwf PORTB movlw B'00000100' ; pull-ups enabled ; prescaler assigned to TMR0 ; prescaler set to 1:16 ; rolls over each 1/125 th second option movlw 0 movwf hr10 movlw H'9' ; initialize hrs, mins and secs movwf hr ; Do this before interrupts are movlw H'5' ; turned on because isr also acts movwf min10 ; on these registers movlw H'0' movwf mins movwf sec10 movwf sec movlw D'125' ; initialize isr counter movwf counter movlw B'10100000' ; GIE & T0IE set, T0IF cleared movwf INTCON return ;----------------------------------------------------------------------; ; Interrupt routine, increments time by one second (BCD) ; ;----------------------------------------------------------------------; isr: movwf w_temp ; save W swapf STATUS,W ; save status movwf status_temp ; without changing flags swapf FSR,W ; save FSR movwf fsr_temp ; without changing flags decfsz counter, f ; skip on 125th time thru goto restore ; else exit movlw D'125' ; reset interrupt counter movwf counter movlw sec ; point at sec register movwf FSR newdigit: incf INDF, f ; current digit up one movlw sec ; get difference sec and FSR subwf FSR, W call sethi ; use to get high limit + 1 subwf INDF, W ; reached that number yet? btfss STATUS, Z ; skip over if yes goto restore ; else exit isr clrf INDF ; set current digit to 0 incf FSR, f ; point at next digit btfss hr10, 1 ; has hr10 reached 2? goto newdigit ; no, increment the next digit btfss hr, 2 ; has hr reached 4? goto newdigit ; no clrf hr ; yes, set hour to 00 clrf hr10 ; and hour 10 restore: swapf status_temp,W ; get original status back movwf STATUS ; into status register swapf fsr_temp,W ; get original fsr back movwf FSR ; into status register swapf w_temp,f ; old no flags trick again swapf w_temp,W ; to restore W bcf INTCON,T0IF ; clear the TMR0 interrupt flag retfie ; finished reset GIE ;----------------------------------------------------------------------; ; Increment and display digit pointed to by FSR ; ;----------------------------------------------------------------------; updigit: incf INDF, f ; selected digit up one movlw mins ; set up to subtract mins address subwf FSR, W ; from address of current digit call sethi ; get maximum of digit + 1 into W subwf INDF, W ; is it = to current digit value? btfsc STATUS, Z ; gives zero if yes, skip if no clrf INDF ; reset value of digit to zero movf INDF, W ; get current value and .. movwf PORTB ; display it call onesecond ; pause for 1 second return ;----------------------------------------------------------------------; ; flash LED representing digit position ; ;----------------------------------------------------------------------; setnext: movwf digit ; save digit position flashloop: clrf PORTB ; all LEDs off movf digit, W ; restore digit position btfss flashcnt, 0 ; leave off on odd #'s of counter movwf PORTB ; flash digit on even #'s movlw 50 ; delay for 50 msec call nmsec incf flashcnt, f ; flip LSB of flashcnt btfss SHOWPB ; skip over if SHOW not pressed call updigit ; else increment current digit btfsc SETPB ; skip over if set pressed goto flashloop ; continue until pressed again incf FSR, f ; set up for next digit call waitsetup ; wait for release return ;----------------------------------------------------------------------; ; Increment and set digits ; ;----------------------------------------------------------------------; setdigits: bcf INTCON, GIE ; no interrupts while setting time movlw mins ; point at minutes register movwf FSR call waitsetup ; wait on set pushbutton up movlw B'00000001' ; light right LED (mins) call setnext movlw B'00000010' ; light min10 LED call setnext movlw B'00000100' ; light hr LED call setnext movlw B'00001000' ; hr10 LED on call setnext clrf PORTB ; clear LEDs bsf INTCON, GIE ; enable interrupts again return ;----------------------------------------------------------------------; ; The main routine ; ;----------------------------------------------------------------------; main: call init ; set up initial conditions loop: btfss SHOWPB ; check for show pushbutton call disptime ; display the time btfss SETPB ; check for setting of time call setdigits goto loop ; do forever end ; Note: A 4.096 MHz xtal is needed for accurate timing over long ; periods. You press the SHOW pushbutton to show the time, digit by ; digit. Zeros are shown as all lights on. To set the time you press ; SET. The right most digit will blink indicating minutes are to ; be set. Pressing SET again chooses tens of minutes etc. After tens ; of hours, the LEDs blank and the clock is timing again. While any ; LED is blinking, pressing SHOW will display that digit value and ; increment it every second. Release SHOW when the digit value is what ; you want.
file: /Techref/piclist/cheapic/binclk4m.asm, 13KB, , updated: 2000/12/8 12:59, local time: 2024/10/8 13:36,
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