At 01:56 PM 5/8/98 +0100, you wrote:
>I think he meant the pin being pulled low either by say a link or
>a logic gate, and the pin being used as an input. i.e. it is tristated.
>This does not involve shorts.
>Register shadowing is needed, because what you read from mixed In/Out
>ports is partly incoming data, and thus not the byte you last wrote to
>the outgoing data buffer. This can cause screw ups when you re-enable
>an input pin as an output pin (for example, as part of a bidirectional
>data path).
>

Well, I understand and agree with you that this is necessary with
bi-directional ports, but the whole point of that last message to which I
responded was that it was not only necessary in the bi-directional case,
but even when a pin remained as just an output! It was that assertion that
I was questioning.

Sean


+--------------------------------+
| Sean Breheny                   |
| Amateur Radio Callsign: KA3YXM |
| Electrical Engineering Student |
+--------------------------------+
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