standard RS 232 input

Siri

I am connecting a standard RS232 input to the propeller.
While reseaching this in the forum there were many discussions as to connecting direcrly to a propeller pin via 10K resistor.
The I found the attached schematic " Sewrial to Propeller" by parallax for programming via RS232.

Can I use this schematic just for the same purpose of receiving serial data from device with standard RS 232 ou-put.

?may be the "serial to propeller" unit will protect the propeller better.

I will appriciate any advise.

Thanks \,

Siri

Leon

I've done that with other chips without any problems.

Leon

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Suzuki SV1000S motorcycle

hippy

I'm doing it with a Propeller. Using a 560K current limiting resistor and a 10K pull-down on the PC side of that. The 560K should probably be lower for higher baud rates but works fine for me at 9600. I take the output pin via 330R just to give it some protection.

deSilva

The transistor solution does not give "protection", but inverts the signals (which can as well be done by software, but the bootstrap routines don't do that, as they are written to work with the USB plug).

The vague try to provide a minus voltage has never been reported to make any difference...

Siri

Thanks for all the help.

Iwill now start building the project.

Siri

Joerg

Hi
My experience with series resistors and simple transistor solutions are rater disappointing.
The other point is that i do not like using devices out of there specifications.

Let me explain:
A logical HI on a RS232 interface is represented by a voltage between -3V to -18V and
a logical LO is represented by +3 to +18V! The range between -3V and +3V is a forbidden zone!!!
You normally do not have any problems with that, but i had during my professional work plenty of trouble to solve
problems on RS232 devices caused by being out of specs.

So my suggestion is: use a interface with a converter chip like MAX3232

Saluti Joerg