First off I've read Philips Fam, my manual and other messages, and I understand the ports when they're set with the Open-Drain with the weak internal pullup-this would be like the standard P1,P2,& P3. Also on the board P1.7 is connected to a switch which is to grnd when open and to 3V when closed.

When P1.7 is configured as Open-Drain(w/o internal pu)I'm assuming this is basically the same as the standard P0 port. Philips says to use it as an input write a 1 to the port bit and this causes the pin to float. On my board it seems to work as an input if a 1 or a 0 is written to the port bit. Either way when the switch is open(grnd) the pin is read low and when closed(3v) the pin is read high. Im kind of confused?


Also on page 2 of Philips...Ports 0 to 3: It says writing 1 to a bit of port 0 causes the output to go high. That's not correct is it?


When I configure P1.7 as a push-pull (w/o the switch)it works correctly as an output. Writing 1 causes the pin to go high and 0 goes low. However, when I connect the switch I couldn't figure out how it operated as a input. Anyone explain the push-pull?

Thanks!!!