If DS18B20 it's in 9 bit mode, the clock run faster (!) with ~ 2 sec/hour (5 sec in 3 hours).
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If DS18B20 it's in 9 bit mode, the clock run faster (!) with ~ 2 sec/hour (5 sec in 3 hours).
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Thats about .055%; you ARE using a crystal, not a resonator, right?
Anand
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Yes, I use a crystal. But, without code for DS18B20, the clock run correct (~ 1 sec/day).
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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?
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Closer to .056, actually since its .055555.. So, you might me spot on..Originally Posted by HenrikOlsson
Anand
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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
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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.
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