using rs232 chips to link io ports

The bmp in the above link shows how I want to use (2) sp232a chips (similar to MAX232) to connect 2 processor's I/O pins together so I don't have to worry about burning out the io pins if they aren't configured as input or outputs which has happened to me before. I did post a question to this effect before and someone recommended using the 232 chips. I just want to make sure it will work.

Dan

dansteely2001 at yahoo dot com

Its just a 1-off and I don't want to take any chances.

Dan

Besides, I might have the 2 processors some distance from each other. Wouldn't the higher voltage levels help in that case?

Dan

Dan

Rob is telling you to put 2K2 resistors between the pins of the two processors and forget the interface chips.

Roger

Dan,

On my screen, the two processors are only less than an inch apart.

In you first message, no mention was make about distance.

What did you expect ???

Dan wrote:

All depends on what you mean by "some distance". IFF I were paranoid, I'd put a transistor/fet with open collector and maybe some clamp diodes on the source end and a pullup followed by a current limiting resistor on the input end and maybe some clamp diodes. Another advantage to the inverter is that you can use a UART internal to the chip to talk to RS232 with the correct polarity.

For short distances, I'd just use the series resistor, but split it up into two pieces, one on each end to give a small amount of protection with shorts, overvoltage, static etc. mike