>

If you have 2 additional I/O lines on the PIC, use one to detect the
power failure and the other to switch on a LED ( to drain the

cap) AFTER you finish writing to the EEPROM.

Pailoor

P.S. Post rejection has started.


> Lynx {Glenn Jones} wrote:
>
> > Hello all,
> > I have a circuit (it contains a pic) which has a couple of rather
> > large
> > aluminum electrolytic capacitors (2200uF) as supply filters. the
> > problem
> > is that when the circuit is turned off, the charge takes a little
> > while to
> > dissipate (i have a power on led in series with a 1K resistor across
>
> > the
> > supply lines) and while its dissipating, the pic among other things
> is
> >
> > still funtioning. I am worred that the pic might end up in one of my
>
> > routines which, for example writes to an I2C EEPROM, and corrupt the
>
> > data
> > there. so what i need is a way to disipate the capacitor reletively
> > quickly after power down. I was thinking of putting a diode in
> paralel
> > in
> > the wrong direction (anode to gnd, cathode to vcc) but i dont think
> > this
> > will work, since the charge in the capacitor is polarized. I hope
> > someone
> > has an idea.. thanks agian
> >
> > --------------------------
> > ---------------------------------------------------
> > A member of the PI-100 Club:
> > 3.1415926535897932384626433832795028841971693993751
> > 058209749445923078164062862089986280348253421170679

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