Counter problem

[lerameur]

Hello,

I am having difficulties troubleshooting this problem. I have a countdown timer and when it comes to 59:51 the next number it turns to is 59:44:
the calculations is good , I did a simulation in excel and the formula does work, what the heck is the problem:
I am using the DS 1337 and pic16F887

OSCCON = %01110000 '8 Mhz
DEFINE OSC 8
ANSELH = 0

'///////////////////////////
'// Interrupt section //
'///////////////////////////


'/////////////////////////
'// LCD configuration //
'/////////////////////////

DEFINE LCD_DREG PORTB 	' Set LCD Data port
DEFINE LCD_DBIT 4 		' Set starting Data bit (0 or 4) if 4-bit bus  RB.4, RB.5, RB.6, RB.7
DEFINE LCD_RSREG PORTB 	' Set LCD Register Select port
DEFINE LCD_RSBIT 1 		' Set LCD Register Select bit
DEFINE LCD_EREG PORTB	' Set LCD Enable port
DEFINE LCD_EBIT 0 		' Set LCD Enable bit
DEFINE LCD_BITS 4 		' Set LCD bus size (4 or 8 bits) '4 therefore put wire at 4, 5, 6 and 7 of LCD
DEFINE LCD_LINES 2 		' Set number of lines on LCD
DEFINE LCD_COMMANDUS 2500
DEFINE LCD_DATAUS 250
DEFINE CHAR_PACING 2000
pause 1000

'/////////////////////////
'// PIN configuration //
'/////////////////////////

TRISB = %00000000 ' Set PORTB to all output
TRISA = %11111111 ' Set PORTA to all input
TRISC = %11000000 ' Set PORTC to all output


'///////////////////////////////////////////////
'// Variable Declaration and initialization //
'///////////////////////////////////////////////

SDApin var PORTC.4                     ' RTC data 
SCLpin var PORTC.3                     ' RTC clock

Total_time var word
RTCSec var byte :RTCMin var byte :RTCHour var byte :RTCWDay var byte :RTCDay var byte :RTCMonth var byte :RTCYear var byte :RTCCtrl var byte 

lcdout $FE,1, "Bienvenue"
lcdout $FE,$C0, "Welcome" 
pause 1000

'////////////////////////////////////////////////////
'////////////////// PROGRAM /////////////////////////
'////////////////////////////////////////////////////

Mainloop:
		if PORTC.6 =0 then 
		Gosub CountDown
				lcdout $FE,1, "Out of Countdown"
				lcdout $FE,$C0, " Press C.6 to Start "
				Pause 150
		Endif
		
goto Mainloop
End

CountDown:
I2CWRITE SDApin,SCLpin,$D0,$00,[$00,$00,$00,$00,$00,$00,$00,$00] ' Write to DS1307 to start counter at ZERO
Pause 20
	while RTCHour != 1

			I2CRead SDApin,SCLpin,$D0,$00,[RTCSec,RTCMin,RTCHour,RTCWDay,RTCDay,RTCMonth,RTCYear,RTCCtrl]  
			Pause 20
				'Will get the time from timer chip and do a 60 min count down
				'Also add interrupt if someone presses start to view the charge/discharge cycle
				 Total_time = (RTCMin * 60) + RTCSec
				 Total_time = 3600 - Total_time
				lcdout $FE,1, "Time left"
				lcdout $FE,$C0, " Diff: ", dec2 RTCHour, ":", dec2 Total_time/60 ,":", dec2 Total_time//60
				Pause 150
	Wend
return

[lerameur]

Hi,

I also tried a clock program with the DS1337, works good, just that the seconds do not stop at 59, it continues to 80....or 89, thats was last night. How can the chip gives me this kinf of values ????

K

[Charles Linquis]

The clock setting and ouput values are in BCD

There are lots of DS1307 examples on the forum that explain the conversion.

[lerameur]

I think it might the mod mode, I will try this tonight, basic basic basic:

while RTCHour != 1

			I2CRead SDApin,SCLpin,$D0,$00,[RTCSec,RTCMin,RTCHour,RTCWDay,RTCDay,RTCMonth,RTCYear,RTCCtrl]  
			Pause 20
				'Will get the time from timer chip and do a 60 min count down
				'Also add interrupt if someone presses start to view the charge/discharge cycle
				 Rest_seconds = 59 - RTCSec
				 Rest_min = 59 - RTCMin 
				lcdout $FE,1, "Time: ", dec2 RTCHour, ":", dec2 RTCMin, ":", dec2 RTCSec
				lcdout $FE,$C0, " Dif: ", dec2 RTCHour, ":", dec2 Rest_min ,":", dec2 Rest_seconds 
				Pause 150
	Wend

[lerameur]

BCD... o crap, yes would explain why it went from 9 to 16 !!!, thanks. Missed that on the spec sheet.

[mackrackit]

sec VAR BYTE ' seconds
mins VAR BYTE ' minutes
hr VAR BYTE ' hours
day VAR BYTE ' day
date VAR BYTE ' date
mon VAR BYTE ' month
yr VAR BYTE ' year
 'DEC VARS
SEC_O   VAR BYTE
SEC_T   VAR BYTE
MIN_O   VAR BYTE
MIN_T   VAR BYTE
HR_O    VAR BYTE
HR_T    VAR BYTE
MON_O   VAR BYTE
MON_T   VAR BYTE
DATE_O  VAR BYTE
DATE_T  VAR BYTE
YR_O    VAR BYTE
YR_T    VAR BYTE

    '#################################################
READ_RTC:
I2CREAD DS_SDA, DS_SCL, RTC, SecReg, [sec,mins,hr,day,date,mon,yr]

SEC_T = sec & $70
SEC_T = SEC_T>>4
SEC_O = sec & $0F

MIN_T = mins & $70
MIN_T = MIN_T>>4
MIN_O = MINs & $0F

HR_T = hr & $70
HR_T = HR_T>>4
HR_O = hr & $0F

MON_T = mon & $70
MON_T = MON_T>>4
MON_O = mon & $0F

DATE_T = date & $70
DATE_T = DATE_T>>4
DATE_O = date & $0F

YR_T = yr & $70
YR_T = YR_T>>4
YR_O = yr & $0F