On Thu, 8 May 2003 11:48:08 -0600, you wrote:
>Except for R-M-W issues.
>
>If you manipulate port RA bits directly, pin RA4 is always going to read
>logic 0 since the E-B forward voltage drop is only about 0.6 .. 0.7V.  =
So:
>you set pin RA4 high.  Now you set pin RA3 high.  Pin RA4 magically goes=
 LO
>by itself.
>
I pretty much gave up on transistors years ago and use logic level =
mosfets
instead. In your example the RA4 pin would be pulled all the way up if
a mosfet was used. If you only have to switch a couple hundred milliamps
or so, something like a ZVN3306A from Zetex works fine and has almost
no gate capacitance to worry about.

crazybob

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