DS1302 Timekeeping chip pauses when I blow on it

Michael Hopcroft

I'm working on an SX-Tech board with a DS1302 timekeeping chip, a DS1620 digital thermometer, and a 2x16 serial LCD.·Every 1/10 second my·SX program polls the timekeeper and the thermomter and then displays the current hours, minutes, seconds, and temperature on the LCD. While debugging the thermometer code I would sometimes blow onto the DS1620 to cause a temperature increase. I noticed that blowing on the DS1620 often caused the time display to pause for a·number seconds and then resume. After a bit of investigation I determined that these pauses seemed to be·caused by a temporary·DS1302 clock stoppage, and not a bug in the SX control flow. Is there any reason that blowing·the circuit could cause the DS1302 clock to pause?

-Mike

Peter Verkaik

If you plugged the 32kHz crystal for the DS1302·into the breadboard,
I can imagine its leads may be temporarily loose contact since these leads
are very thin and not really suited for breadboard use. If you wiggle the crystal
you probably get the same error.

regards peter

bassmaster

try just placing your finger, (static wristband attatched), on the temp chip, you should not see a pause when the temp goes up.

Philip Gamblin

I anticipated a problem like that so I soldered the xtal directly to the pins of the chip, tacked the xtal in place with hot glue,·and socketed the entire arrangement. Hot glue guns are great small "potting" jobs.

Post Edited (Philip Gamblin) : 3/13/2007 1:30:49 AM GMT