AVR-Chat

At 12:25 AM 21/06/2007, you wrote:
>the 49 Ohm pull up resistor at the other end of the line.

The first thing is to try and remove the possibility of shorts
to VCC.

Is the resistor tied up to 5V at the other side? That would be
a 100mA sink you are trying to get from a pin!! Even at 3.3V it is
still about 70mA. Then you have to consider the possibility of having
you board powered off and the other powered on (maybe it can't happen??).

As a minimum I would fit an open connector (drain) driver and perhaps
even a small fuse.


Regards

John Samperi

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Ampertronics Pty. Ltd.
11 Brokenwood Place Baulkham Hills, NSW 2153 AUSTRALIA
Tel. (02) 9674-6495       Fax (02) 9674-8745
Email: john@ampertronics.com.au
Website  http://www.ampertronics.com.au
*Electronic Design * Custom Products * Contract Assembly
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