Serial Question

[penelopepug]

Thanks Dave. I understand the use of an open collector output however what I do not understand is if for example; If I use Porta.4 of a PIC16F877 as my serial output, since it is an open collector output, how would setting the baud to ON1200 differ from N9600? A pull-up is required on the open collector so would N9600 not act exactly the same as ON9600? What does the open collector designation "O" do?

[keithdoxey]

Just guessing that instead of the pin having the two states

OUTPUT HIGH
OUTPUT LOW

it achieves Open Collector functionality by having the two states

INPUT (high impedance so effectively open collector)
OUTPUT LOW

Regards

[penelopepug]

Keithdoxy, you may be right! That's interesting because what you suggest says that ON1200 may instantly change the pin to an input when the bit needs to be high (1) and then changes back to an output to go low (0) in sending the bit stream. Therefore emulating an open collector via the input state when a high (1) is needed. That would help me out because in some programs (using N1200 for example) I have been making the pin an input after sending serial data out because of parallel serial lines. The "O" may take care of that at a bit level.