Don't know how it will work on 3V, but at 5V you can connect a Pic output
directly to a 232 input, no resistors needed.  You can connect a 232 output to a
PIC input pin through a 22K resistor.

A computer 232 port will read without doing anything to the RTS, CTS, etc.
lines, but to get it to transmit you need to connect some lines together, but I
don't remember which ones off the top of my head.  Can someone help me out?

Dan Rosenfeld wrote:

> Hi all,
>
> >From looking at the archive, I can see that this is a somewhat FAQ.
> Unfortunately, I'm having trouble assembling all that I've read into a
> coherent picture applicable to my simple problem....
>
> I'd like be able to send characters (debugging printfs) from the 16LF84 in
> my circuit to my PC serial port W/O USING A LEVEL CONVERTER CHIP. I only
> need this to work on my PC for debugging purposes (it's not a production
> circuit) and at low baud rates and short cable distances. I'm also wondering
> whether I can get away with running this all at Vdd = 3.0V (thus the LF84)
> or will I need run at some higher voltage while debugging.
>
> I'm pretty clear on the PC side (terminal emulator app or basic program),
> but I'm not certain of the exact electrical connections on the pic side.
> I've seen mention of using anywhere from 1k to 1meg in series w/o tx/rx
> lines and along with some mention of pulldowns on these lines.
>
> Also, do I need to do anything special with any of the other rs-232 lines
> such as RTS/DTS, etc. or can I just let them float? (Assuming the pc
> software is configured correctly.)
>
> So, what's the *exact* wiring/circuit that I should use here ?
>
> (BTW, inside the PIC I'm planning on using the CCS compiler's serial IO
> routines.)
>
> Thanks in advance,
>
> Dan