in micro controllers 8051 the ports 1,2,3 consists internally pull up resisters but why the port0 is not?

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2007-06-23 22:51:49 · 2 answers · asked by badri r 1 in Science & Mathematics ➔ Engineering

Port 0 is a true bi-directional port, not a pseudo-bidirectional port (like 1, 2, and 3), so it doesn't need the pullups.

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2007-06-25 06:31:40 · answer #1 · answered by tlbs101 7 · 0⤊ 0⤋

So that you can connect all ports to form the wired-OR.

2007-06-24 01:06:13 · answer #2 · answered by fernando_007 6 · 0⤊ 0⤋