It happens even if i run the clock from a battery.
It sometimes locks up when i plug in the cellphone charger adapter.
Will decoupling capacitors or line filters help?
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It happens even if i run the clock from a battery.
It sometimes locks up when i plug in the cellphone charger adapter.
Will decoupling capacitors or line filters help?
|
If you don't have decoupling capacitors, it could be a problem.
I usually put a .1uF (100nf) across the power rails for every 2-3 chips.
Some people say 1 cap per chip, but I think that's a little more than necessary.
You shouldn't need RF sheilding.
<br>
DT
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Decoupling capacitors don't seem to help . . .
Using the 16F628A with MCLR disabled while programming solves the problem (for now)...
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Hi shahidali55,
If your display is large and has long wires , it may well be acting as an antenna, try decoupling caps on each output line going to it, as well as any inputs, also try hooking all ground connections to a single ground connection, as ground loops often cause electronic circuits to oscillate, That is what they used to do in high end audio gear.
HTH
JS
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Hello Joe,
My display is large and there are a lot of long wires running around and there are 2 ground loops.
How should i add decoupling capacitors to the output and input pins ?
I have attached a few photos of the complete clock and PCB side. . .
(They may take a while to download)
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Hi shahidali55,
On the perfboard I would probably run a buss wire lengthwise under the pic and from each pin I would add .o1uf or even .001 uf capacitors to the buss wire which is hooked up to ground, I think you are getting RF into the chip from the outputs, RF is funny, it sort of crawls on the outside of conductors and does funny things. AS for things like cellphone chargers emitting RF I guess it depends upon which country's emission standards they meet or fail to meet. You might try using 2 bypass caps, 1 from each leg of the Mains power to ground right at the outlet. Ferrite beads are useful to trap RFI on wires on the circuit board. Be sure they are made for that high of a voltage,otherwise they pop like firecrackersSome links on RFI:
http://www.edn.com/archives/1995/010595/01df1.htm
http://www.eham.net/articles/12139
Last edited by Archangel; - 29th January 2008 at 08:02.
If you do not believe in MAGIC, Consider how currency has value simply by printing it, and is then traded for real assets.
.
Gold is the money of kings, silver is the money of gentlemen, barter is the money of peasants - but debt is the money of slaves
.
There simply is no "Happy Spam" If you do it you will disappear from this forum.
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16F628A has been running stable for 10 days now.(Tried doing all sorts of things to make it reset, but its immunity is really good).
So i guess the only solution is to stick with the 16F628A . . .
Last edited by shahidali55; - 8th February 2008 at 16:46.
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