DS1302 running slow

BobVal

Hello:

I took all the parts off my breadboard and soldered them onto my super carrier board and now my clock is ticking very slow.

Software wise everything seems to be working fine.·

The clock I have displaying is ticking very slowly which leads me to believe that I did something to the DS1302 or the Crystal.·
Everything worked fine on the breadboard (clock kept perfect time for days, now off in minutes)

Should I start with the Crystal or DS1302.

Is it possible to install the clock crystal (I believe it is the··XTAL-32.768 kHz), backwards?· Or did I just burn it out?

Bob

·

Peter Verkaik

The crystal is non-polarized so you cannot have it backwards.
Check all the solder joints. See if you can recreate the schematic
from the soldered connections and see if that matches your
original schematic. It·may be·that you made an incorrect
connection or left a connection out.
If you write· a value into a ram register, do you read the same value back?
Try different values.

regards peter

JFReyes

I also had the same problem and ended up soldering the crystal directly on the chip's pins (very carefully). Problem solved.

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Jos

BobVal

Tried touching up the solder joints on the crystal, still runs slow (checked all contacts with a meter and everything seems fine).

De-soldered the old crystal and soldered one right onto the chip.

Now everything is working perfect.

Thanks

BobVal

PS: I think the problem could have been I pulled the crystal too close to the board and was making contact with the shell (the shell was not grounded to anything) and the solder pad.

Not sure if that would cause a problem but maybe

JFReyes

...And therefore introduced additional capacitance that would slow its oscillations down. The length of the connection is critical, even if it's good electrically. Glad you solved it.

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Jos