real time clock

[bahattinkor]

yes, I checked connections. voltages are normal but when I measured the cyrstal of Ds1302 with ossiloscope, I did not see any frequency. The ossilator does not ossilates. then I change DS1302 and 32.768Khz cyrstal with new ones but they are still not working. Can it be related with the Vcc that I used. I use 5V for Vcc for DS1302. Or Should I use any resistor or capacitor plus for the DS1302.

[mister_e]

Probably your Clock Halt flag is set..... it's undetermined when you put power on the RTC. Just clear this bit and you'll see oscillation on your scope.
The problem is the same on many RTC. See the secondes register for the CH bit.

Many cheaper probe will screw the signal coming from an Crystal. Place it on 10X and this will help a bit in many case.

[sayzer]

Here is a modified version of the code posted by CocaColaKid above.

In the code above, the clock can only be set during the programming of PIC.

With the modification here, the user can set the time, date etc. at any given time.

Advise/post any additions, recommendations, modifications etc if any.

[sayzer]

As members are asking;

Attached is the updated version with more space.
(HEX Conversion is shorter)

------------------------------------------------------

[shahidali55]

Hey CocaColaKid,
Your code for the DS1302 is really good and efficient...
I got a few questions,
how should i enable the trickle charge option ?
and how should i clear or set the clock halt flag???

[Russ Kincaid]

I am a neophyte at programming, but have been writing BASIC code for 40 years. This is how I would do the conversion:

DECX VAR BYTE(59)
A VAR BYTE
B VAR BYTE
C VAR BYTE

FOR B = 0 TO 59
FOR A = $0 TO $59
IF C = B THEN DECX(C) = A
C = C+1
NEXT A

NEXT B
' THIS ROUTINE GENERATES AN ARRAY WHERE
' DECX(0) = $0
' DECX (1) = $1
' ETC.
I didn't do it correctly the first time, this is better.

[blainecf]

For all you old timers, here's an alternate way of calculating Human Date/Time from the RTC bits:

(Also, because all info is read in one shot, there is less liklihood that the seconds won't match the minutes.)

I2CREAD DPIN,CPIN,RTC,I2C_Adr_B,[Rd_seconds, rd_minutes, rd_hours, Rd_DOW, Rd_DAy, RD_month, Rd_Year] ' in bcd code

Seconds = Rd_Seconds.0 + (Rd_Seconds.1 * 2) + (rd_seconds.2 * 4) + (rd_Seconds.3 * 8) + (rd_seconds.4 * 10) + (rd_seconds.5 * 20) + (Rd_Seconds.6 * 40)

Minutes = Rd_Minutes.0 + (Rd_Minutes.1 * 2) + (rd_Minutes.2 * 4) + (rd_Minutes.3 * 8) + (rd_Minutes.4 * 10) + (rd_Minutes.5 * 20) + (Rd_Minutes.6 * 40)

Hours = RD_Hours.0 + (Rd_hours.1 * 2) + (rd_hours.2 * 4) + (rd_hours.3 * 8) + (rd_hours.4 * 10)

am_pm = rd_hours.5
dow = rd_dow

day = rd_day.0 + (rd_day.1 * 2) + (rd_day.2 * 4) + (rd_day.3 * 8) + (rd_day.4 * 10) + (rd_day.5 * 20)

Month = rd_month.0 + (rd_month.1 * 2) + (rd_month.2 * 4) + (rd_month.3 * 8) + (rd_month.4 * 10)

Year = rd_year.0 + (rd_year.1 * 2) + (rd_year.2 * 4) + (rd_year.3 * 8) + (rd_year.4 * 10) + (rd_year.5 * 20) + (rd_year.6 * 40) + (rd_year.7 * 80)