A Tale of Voltaic Experience

RiJoRi

I'm kinda new to the Stamp, but an "oldbie" when it comes to micros.

I decided to take a couple of projects from the Nuts & Volts articles -- driving a 4-bit wide LCD, and reading and writing the DS1302. I wanted a Calendar/Clock display.

I finally got it going last night, and forgot to unplug the battery but did not realize it until this morning. The result was that the clock seemed to have stopped updating the seconds, BUT the display was working fine.

Coming home from work, I started fiddling with the code, trying to figure out why the seconds were not updating, and why the Clock Halt flag was set. I checked the power going to the DS1320, and found it to be 4.70V or so. So I hooked up a 9VDC wall wart to the power, and STILL NOTHING!!! I finally cranked up my o'scope, and checked the Vcc. There was at least a half volt's worth of noise on the line! I put caps (0.01uF & 0.1uF) all over the place, including where the wall wart was delivering the power. The noise went away, and my clock is now ticking.

Hope this can help somebody else,
--Rich

Prettybird

With cheap electronic power supplys sometimes a Big cap like 100 to 500 MFD and a small .01 will work too. I learned in an industrial enviorment. Shops have higher voltages alnd lots of noise.