> it's an open drain output, -what does that mean exactly,

It can pull the voltage low but not high.  "Normal" outputs can pull in
both directions.  This means that if you set the open drain pin as an
output and write a 0 to it, it will go low like a normal output.  Writing
a 1 to it causes it to float to whatever the external circuit wants.

> this has come about because I cannot get the LED to blink on this pin,
RA4
>
> I tried setting adcon1 to 6, and trisa to 0
> but there is something else, or all my pics are damaged exactly the same
> way.

I doubt they are damaged.  To use RA4 to blink an LED, connect the LED
anode to +5V, the cathode to a 430ohm (or thereabouts) resistor, and the
other end of the resistor to the RA4 pin.  Set bit 4 of TRISA to 0 to make
it an output.  Now when you set bit 4 of PORTA to 0 the LED will go on,
and when you set bit 4 of PORTA to 1 the LED will go off.


*****************************************************************
Embed Inc, embedded system specialists in Littleton Massachusetts
(978) 742-9014, http://www.embedinc.com

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics