|
Hi,
If I read this correctly you have an interrupt frequency of 61.035Hz (prescaler 1:64, 256*64=16384, 1/0.016384=61.035Hz) when you ideally should have 61Hz - that's 0.057% off and as Anand says 2 seconds over one hour is 0.055%.
I currently have no idea why it starts running correct when you remove the DS1820 code - are you sure that's the case?
|
Closer to .056, actually since its .055555.. So, you might me spot on..Originally Posted by HenrikOlsson
Anand
|
Somebody, in a forum of my country, propose this code. It' work ok, just 1 sec/hour faster !
Code:@ __config _XT_OSC & _WDT_OFF & _PWRTE_OFF & _MCLRE_OFF & _LVP_OFF & _CP_OFF define OSC 4 TRISA= %11111000 ' RA0..3=Outputs RA4=Input TRISB= %00001111 ' RB0..RB2=Inputs, RB3..RB7=Outputs CMCON=7 ' Disable comparators OPTION_REG=%00000111 DEFINE LCD_DREG PORTB ' LCD on port B DEFINE LCD_DBIT 4 ' Data bits B4..B7 DEFINE LCD_RSREG PORTA ' RS on PORTA DEFINE LCD_RSBIT 1 ' RS on A1 DEFINE LCD_EREG PORTA ' E on PORTA DEFINE LCD_EBIT 0 ' E on A0 DEFINE LCD_BITS 4 ' LCD 4 bit mode DEFINE LCD_LINES 2 ' 2 line LCD display wsave VAR BYTE $70 SYSTEM TempC var word Float var word Sign var bit ' +/- sign DQ var PORTA.4 ' One-wire data pin TempC2 var word Float2 var word Sign2 var BIT ' +/- sign DQ2 var PORTA.3 ' One-wire data pin Delay var byte Mode var byte semn var word semn2 var word INCLUDE "DT_INTS-14.bas" ; Base Interrupt System ; Attention ! Modified file ! INCLUDE "ReEnterPBP.bas" DS18B20_1_12bit CON %00011111 ' NOW 9 BIT DS18B20_2_12bit CON %00011111 ' NOW 9 BIT Ticks var byte ; Tick count (61 ticks=1 sec) Hour var byte ; Hour variable Minute var byte ; Minute variable Second var byte ; Second variable ZIUA var byte LUNA var byte Disp var BIt ; Disp=1 to update display PAUSE 500 ; Wait 0.5sec for LCD to initialize Hour=0 : Minute=0 : Second=0 Ticks=0 : ZIUA=01 : LUNA=01 ' Init Sensor 1 OWOUT DQ, 1, [$CC, $4E, 0, 0, DS18B20_1_12bit] OWOut DQ, 1, [$CC, $48] OWOut DQ, 1, [$CC, $B8] OWOut DQ, 1, [$CC, $BE] Pause 50 OWIn DQ, 2, [TempC.byte0, TempC.byte1] Pause 50 ' Init Sensor 2 OWOUT DQ2, 1, [$CC, $4E, 0, 0, DS18B20_2_12bit] OWOut DQ2, 1, [$CC, $48] OWOut DQ2, 1, [$CC, $B8] OWOut DQ2, 1, [$CC, $BE] Pause 50 OWIn DQ2, 2, [TempC2.byte0, TempC2.byte1] Pause 50 OPTION_REG=$05 ; Set prescaler INTCON=$A0 ; Enable TMR ASM INT_LIST macro ; IntSource, Label, Type, ResetFlag? INT_Handler TMR0_INT, _ISR, PBP, yes endm INT_CREATE ; Creates the interrupt processor ENDASM @ INT_ENABLE TMR0_INT LCDOUT $FE, 1 ; Clear LCD LOOP: If PORTB.0=0 then ' Mode switch preSeconded Pause 50 ' Debounce LcdOut $FE, 1 LcdOut $FE, $C0, " SETTING" ' Show that coMinuteand is accepted PAUSE 500 LcdOut $FE, 1 If PORTB.0=0 then Loop ' Wait until button is released Mode=Mode+1 ' Increment mode ENDIF If Mode=1 then ' SET HOUR LcdOut $FE, $80, dec2 Hour LcdOut $FE, $C0, "HOUR SETTING" if portb.1=0 then Hour=Hour+1 IF Hour=24 then Hour=0 ENDIF Gosub Debounce endif if portb.2=0 then IF Hour = 0 then Hour=24 ENDIF Hour=Hour-1 Gosub Debounce endif EndIf If Mode=2 then ' SET MINUTES LcdOut $FE, $80, dec2 Hour,":",dec2 Minute LcdOut $FE, $C0, "MINUTES SETTING" if portb.1=0 then Second=0 Minute=Minute+1 IF Minute=60 THEN Minute=0 ENDIF Gosub Debounce endif if portb.2=0 then Second=0 IF Minute =<0 THEN Minute=60 ENDIF Minute=Minute-1 Gosub Debounce endif EndIf If Mode=3 then ' SET DAY LcdOut $FE, $80, dec2 Hour,":",dec2 Minute,":",dec2 Second," ",DEC2 ZIUA,"/" LcdOut $FE, $C0, "DAY SETTING" if portb.1=0 then ziua=ziua+1 IF LUNA=2 THEN IF ZIUA > 28 THEN ZIUA=1 ENDIF ENDIF IF LUNA=4 OR LUNA=6 OR LUNA=9 OR LUNA=11 THEN IF ZIUA > 30 THEN ZIUA=1 ELSE IF ZIUA > 31 THEN ZIUA=1 ENDIF Gosub Debounce endif if portb.2=0 then ZIUA=ZIUA-1 IF ZIUA = 0 THEN ZIUA=31 Gosub Debounce endif EndIf If Mode=4 then ' SET MONTH LcdOut $FE, $80, dec2 Hour,":",dec2 Minute,":",dec2 Second," ",DEC2 ZIUA,"/",DEC2 LUNA LcdOut $FE, $C0, "MONTH SETTING" if portb.1=0 then luna=luna+1 if luna>12 then luna=1 endif Gosub Debounce endif if portb.2=0 then luna=luna-1 if luna<1 then luna=12 endif Gosub Debounce endif EndIf If Mode > 4 then LCDOUT $FE, $C0, "END SETTING" PAUSE 100 LCDOUT $FE, 1, $FE, $0C mode=0 EndIf If Mode > 0 then Loop IF Disp=1 THEN LcdOut $FE, $80, DEC2 Hour, ":",DEC2 Minute, ":",DEC2 Second," ",DEC2 ZIUA,"/",DEC2 LUNA LCDOUT $FE, $C0, semn,DEC ABS TempC/100,".", DEC1 ABS TempC/10, 223,"C ", $FE, $C0 + 9, semn2,DEC ABS TempC2/100,".", DEC1 ABS TempC2/10, 223,"C " Disp=0 ENDIF GOTO LOOP @ INT_DISABLE TMR0_INT ISR: Ticks=Ticks + 1 IF Ticks < 61 THEN NoUpdate Ticks=0 Second=Second + 1 ; Update second IF Second=60 THEN Second=0 Minute=Minute + 1 ; Update Minute IF Minute=60 THEN Minute=0 Hour=Hour + 1 ; Update Hour IF Hour=24 THEN Hour=0 ZIUA=ZIUA+1 IF LUNA=2 THEN IF ZIUA > 28 THEN ZIUA=1 LUNA=3 ENDIF ENDIF IF LUNA=4 OR LUNA=6 OR LUNA=9 OR LUNA=11 THEN IF ZIUA > 30 THEN ZIUA=1 LUNA=LUNA+1 ENDIF ENDIF IF LUNA=1 OR LUNA=3 OR LUNA=5 OR LUNA=7 OR LUNA=8 OR LUNA=10 THEN IF ZIUA > 31 THEN ZIUA=1 LUNA=LUNA+1 ENDIF ENDIF IF LUNA=12 THEN IF ZIUA > 31 THEN ZIUA=1 LUNA=1 ENDIF ENDIF ENDIF ENDIF ENDIF Gosub Read_temp Disp=1 ; Set to update display NoUpdate: INTCON.2=0 ; Re-enable TMR0 interrupts @ INT_RETURN ; Re-enable interrupts END ;================================= ;Subrutine Debounce: FOR Delay=1 To 200 Pause 1 ; Delay 1ms inside a loop. This way, NEXT Delay ; timer interrupts are not stopped Disp=1 ; Set display flag to 1 RETURN ;================================== Read_Temp: OWOut DQ, 1, [$CC, $44] OWOut DQ, 1, [$CC, $BE] OWIn DQ, 2, [TempC.byte0, TempC.byte1] Sign = TempC.15 TempC = ABS(TempC) TempC = ((TempC >> 4)*100) + ((TempC & $F)*100 >> 4) IF Sign THEN TempC = -TempC IF TempC.15 THEN Semn="-" else Semn="+" endif OWOut DQ2, 1, [$CC, $44] OWOut DQ2, 1, [$CC, $BE] OWIn DQ2, 2, [TempC2.byte0, TempC2.byte1] Sign2 = TempC2.15 TempC2 = ABS(TempC2) TempC2 = ((TempC2 >> 4)*100) + ((TempC2 & $F)*100 >> 4) IF Sign2 THEN TempC2 = -TempC2 IF TempC2.15 THEN Semn2="-" else Semn2="+" endif Return ;===================================== END ; End of program
|
Great - as long as it works for your needs.
But you can't get away from the fact that you're interrupting at 61.035Hz while it ideally should be 61Hz. That little difference WILL make it run fast.
Let's see.... For a duration of 100.000 interrupts a time of 100,000/61.035=1638.40 seconds have passed. Your code, because it divides by 61, will "display" 1639.34 seconds (the clock runs fast).
Here's an idea... If you keep a second WORD sized tick counter incrementing in your ISR and when it hits 1754 you reset it to zero and skip updating your normal Ticks variable for that interrupt only. This way, in 100,000 interrupts you'll only increment your Ticks variable 100,000 - (100,000/1754) = 99943 times, resulting in "time" of 99943/61 = 1638.40 seconds - pretty darn close to ideal. The clock will zig-zag a little bit but the period is only about 28 seconds so I don't think you'll notice.
It's still early here, I may have made some terrible misstake in the math (doesn't have to be early for that). Anyway, it's an idea you may want to look into.
/Henrik.
|
If You see one crazy man, it's me !
I re-re-re-read all the topics on this forum (searching for "timer") and I found one code (Josepino's code) for HIGH-accuracy clock.
I try to compile them, but I have errors. What I do wrong ?
Code:DEFINE NO_CLRWDT Define OSC 4 DEFINE LCD_DREG PORTB ' LCD Data Port DEFINE LCD_DBIT 4 ' Starting Data Bit DEFINE LCD_RSREG PORTA ' Register Select Port DEFINE LCD_RSBIT 1 ' Register Select Bit DEFINE LCD_EREG PORTA ' Enable Port DEFINE LCD_EBIT 0 ' Enable Bit DEFINE LCD_BITS 4 ' Data Bus Size DEFINE LCD_LINES 2 ' Number of Lines on LCD DEFINE LCD_COMMANDUS 2000 DEFINE LCD_DATAUS 50 TRISA= %11111000 ' RA0..3=Outputs RA4=Input TRISB= %00001111 ' RB0..RB2=Inputs, RB3..RB7=Outputs CMCON = 7 pushButton1 var portb.0 'switch pushButton2 var portb.1 pushButton3 Var portb.2 pushButton4 Var portb.3 pressed con 0 ;value of button pressed notPressed con 1 ;value of button not pressed dhour var byte ' Define display hour variable i var byte ' Debounce loop variable ticks var byte ' Define pieces of seconds variable Seconds var byte Minutes var byte Hours var byte Days var byte Months var BYTE TempC var word Float var word Sign var bit ' +/- sign DQ var PORTA.4 ' One-wire data pin TempC2 var word Float2 var word Sign2 var bit ' +/- sign DQ2 var PORTA.3 ' One-wire data pin semn var word semn2 var word DS18B20_1 CON %01011111 DS18B20_2 CON %01011111 ;DS18B20_9bit CON %00011111 ; 93.75ms, 0.5°C ;DS18B20_10bit CON %00111111 ; 187.5ms, 0.25°C ;DS18B20_11bit CON %01011111 ; 375ms, 0.125°C SecondsChanged var bit MinutesChanged var bit HoursChanged var bit DaysChanged var bit SecondsChanged = 1 MinutesChanged = 1 Seconds = 0 Minutes = 0 Hours = 12 Days = 1 Months = 1 SecondsChanged = 1 MinutesChanged = 1 HoursChanged = 1 DaysChanged = 1 include "timp.pbp.txt" Pause 200 ' Wait for LCD to Initialize ' Init Sensor 1 OWOUT DQ, 1, [$CC, $4E, 0, 0, DS18B20_1] OWOut DQ, 1, [$CC, $48] OWOut DQ, 1, [$CC, $B8] OWOut DQ, 1, [$CC, $BE] Pause 50 OWIn DQ, 2, [TempC.byte0, TempC.byte1] Pause 50 ' Init Sensor 2 OWOUT DQ2, 1, [$CC, $4E, 0, 0, DS18B20_2] OWOut DQ2, 1, [$CC, $48] OWOut DQ2, 1, [$CC, $B8] OWOut DQ2, 1, [$CC, $BE] Pause 50 OWIn DQ2, 2, [TempC2.byte0, TempC2.byte1] Pause 50 mainloop: if tick.0=1 then tick.0=0 Seconds = Seconds + 1 SecondsChanged = 1 if Seconds = 60 then Minutes = Minutes + 1 MinutesChanged = 1 Seconds = 0 endif if Minutes = 60 then Hours = Hours + 1 HoursChanged = 1 Minutes = 0 endif if Hours = 24 then Days = Days + 1 DaysChanged = 1 Hours = 0 endif if Days = 32 then Months = Months + 1 Days = 1 endif if months = 13 then months = 1 endif endif ' Check button pressed to set time if pushbutton1 = pressed Then gosub set_minutes endif if pushbutton2 = pressed then gosub set_hours endif if pushbutton4 = pressed then gosub set_days endif if pushbutton3 = pressed then gosub set_Months endif ' Check for time to update screen If SecondsChanged = 1 Then SecondsChanged = 0 ' Display time as hh:mm:ss LCDout $FE, $80, dec2 Hours,":",dec2 Minutes,":",dec2 Seconds," ",DEC2 Days,"/",DEC2 Months LCDOUT $FE, $C0, semn,DEC ABS TempC/100,".", DEC1 ABS TempC/10, 223,"C ", $FE, $C0 + 9, semn2,DEC ABS TempC2/100,".", DEC1 ABS TempC2/10, 223,"C " ' pauseus 1386 Endif Goto mainloop ' Do it all forever set_minutes: Minutes = Minutes + 1 if Minutes = 60 then Minutes = 0 endif gosub debounce return set_hours: Hours = Hours + 1 if Hours = 24 then Hours = 0 endif gosub debounce return set_days: Days = Days + 1 if Days = 32 then Days = 1 endif gosub debounce return set_months: Months = Months +1 if Months = 13 then Months = 1 endif gosub debounce return debounce: For i = 1 To 100 ' Debounce and delay for 100ms Pause 1 ' 1ms at a time so no interrupts are lost Next i SecondsChanged = 1 return ;=================================================== Read_Temp: ' Skip ROM search & do temp conversion OWOut DQ, 1, [$CC, $BE] OWIn DQ, 2, [TempC.byte0, TempC.byte1] Sign = TempC.15 TempC = ABS(TempC) TempC = ((TempC >> 4)*100) + ((TempC & $F)*100 >> 4) IF Sign THEN TempC = -TempC IF TempC.15 THEN Semn="-" else Semn="+" endif OWOut DQ2, 1, [$CC, $BE] OWIn DQ2, 2, [TempC2.byte0, TempC2.byte1] Sign2 = TempC2.15 TempC2 = ABS(TempC2) TempC2 = ((TempC2 >> 4)*100) + ((TempC2 & $F)*100 >> 4) IF Sign2 THEN TempC2 = -TempC2 IF TempC2.15 THEN Semn2="-" else Semn2="+" endif Return ;=================================================== End
and timp.pbp.txt
Code:INCLUDE "DT_INTS-14.bas" ; Base Interrupt System ASM INT_LIST macro ; IntSource, Label, Type, ResetFlag? INT_Handler TMR0_INT, int_handler, ASM, yes endm INT_CREATE ; Creates the interrupt processor INT_ENABLE TMR0_INT ; Enable Timer 1 Interrupts ENDASM OPTION_REG = %00001000 ' Set TMR0 configuration INTCON = %10100000 ' Enable TMR0 interrupts bres_hi VAR BYTE bank0 system ' hi byte of our 24bit variable bres_mid VAR BYTE bank0 system ' ; mid byte bres_lo VAR BYTE bank0 system '; lo byte '; (we only need 3 bytes for this system) bres_hi = $0F bres_mid= $42 bres_lo= $40 tick VAR BYTE bank0 system ASM ;****************************************************************************** ; INTERRUPT HANDLER (runs this code each timer0 interrupt) ;****************************************************************************** ; ;------------------ int_handler ; ;------------------ ;------------------------------------------------- ;------------------------------------------------- ; Note! we get here every 256 instructions, we ; can now do our special one second timing system. ; This consists of three main steps; ; * subtract 256 counts from our 24bit variable ; * test if we reached the setpoint ; * if so, add 1,000,000 counts to 24bit variable and generate event. ;------------------------------------------------- ; * optimised 24 bit subtract here ; This is done with the minimum instructions. ; We subtract 256 from the 24bit variable ; by just decrementing the mid byte. tstf bres_mid ; first test for mid==0 skpnz ; nz = no underflow needed decf bres_hi,f ; z, so is underflow, so dec the msb decfsz bres_mid,f ; dec the mid byte (subtract 256) ; now the full 24bit optimised subtract is done! ; this is about 4 times faster than a "proper" ; 24bit subtract. goto int_exit ; nz, so definitely not one second yet. ; in most cases the entire 'fake" int takes ; only 9 instructions. ;------------------------ ; * test if we have reached one second. ; only gets here when mid==0, it MAY be one second. ; only gets to here 1 in every 256 times. ; (this is our best optimised test) ; it gets here when bres_mid ==0. tstf bres_hi ; test hi for zero too skpz ; z = both hi and mid are zero, is one second! goto int_exit ; nz, so not one second yet. ;------------------------------------------------- ; Only gets to here if we have reached one second. ; now we can generate our one second event, like add ; one second to our clock or whatever. ; (in this example we toggle a led) ; The other thing we need to do is add 1,000,000 counts ; to our 24bit variable and start all over again. ;------------------------------------------------- ; Add the 1,000,000 counts first. ; One second = 1,000,000 = 0F 42 40 (in hex) ; As we know hi==0 and mid==0 this makes it very fast. ; This is an optimised 24bit add, because we can ; just load the top two bytes and only need to do ; a real add on the bottom byte. This is much quicker ; than a "proper" 24bit add. movlw 0x0F ; get msb value movwf bres_hi ; load in msb movlw 0x42 ; get mid value movwf bres_mid ; load in mid movlw 0x40 ; lsb value to add addwf bres_lo,f ; add it to the remainder already in lsb skpnc ; nc = no overflow, so mid is still ok incf bres_mid,f ; c, so lsb overflowed, so inc mid ; this is optimised and relies on mid being known ; and that mid won't overflow from one inc. ; that's it! Our optimised 24bit add is done, ; this is roughly twice as quick as a "proper" ; 24bit add. ;------------------------- ; now we do the "event" that we do every one second. ; Note! for this example we toggle a led, which ; will give a flashing led which is on for a second ; and off for a second. ; Add your own code here for your one second event. ; Note! My led is on porta,3 ; your led may be on a different pin. movlw b'00000001' ; mask for bit 3 xorwf tick,f ; toggle PORTA,bit3 (toggle the led) ;------------------------------------------------- ; now our one second event is all done, we can exit the ; interrupt handler. ;------------------------------------------------- ; finally we restore w and status registers. ; also clears TMRO int flag now we are finished. int_exit INT_RETURN ENDASM
Members who have read this thread : 0You do not have permission to view the list of names.
Posting Permissions
Bookmarks