>  Now, the system has a RTC on it and a PIC (16C63B) the problem I'm
> having is that some RTCs (DS1307) are being damaged and I think is due
> to static....

Well, from the the photo the switches and LEDs *look* like they would have a 
fair amount of distance from static fingers by the plastic insulation. Given all 
the good suggestions so far on reducing the amount of static present, next 
thing you should look at is hardware/software modifications to reduce the 
effects of static zaps when they do happen.

For starters, switch inputs should have clamping diodes plus series resistors 
before micro inputs. PSU rail should have zener or TVS overvoltage 
protection, and generous capacitance after regulator.

Here's a few guesses at the problem...the DS1307 is a two wire device 
right(?), which means it shares it's input (more static sensitive) with it's 
supply pin - which might mean that if this device is being killed by static it 
would probably be from coupling along the power supply line. We've talked 
about zaps coming through switches and LED display - what about when the 
user changes batteries? (if it uses batteries). Zaps coming through the 
battery connections could be more likely than through the front panel. Or if 
there is a situation when the user can touch the back of the PCB it would be 
even worse.

Also think about less direct causes. What if simple corruption of the RTC 
registers (or micro registers even) causes your software to misbehave and 
you mistakenly conclude that the RTC is dead? It is more likely that ESD 
onto or nearby would at first corrupt data before before causing hardware 
failures.

Best regards, Brent.
-- 
Brent Brown, Electronic Design Solutions
16 English Street, Hamilton 2001, New Zealand
Ph: +64 7 849 0069
Fax: +64 7 849 0071
Cell/txt: 025 334 069
eMail:  brent.brown@clear.net.nz


-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist