Trigger PIC with PC serial port

[sprntrcr]

So I'm working on a PIC project that would be triggered from a PC serial port. The software (commercial program) can either send the trigger on pin 4 or pin 7 of the COM port. I'm only looking for a trigger and not serial communications, so I'm hoping for something simpler than using a MAX232. Any ideas of how to interface the RS-232 pin to a PIC 16F628 I/O pin?


Thanks....

 

[Nigel Goodwin]

So I'm working on a PIC project that would be triggered from a PC serial port. The software (commercial program) can either send the trigger on pin 4 or pin 7 of the COM port. I'm only looking for a trigger and not serial communications, so I'm hoping for something simpler than using a MAX232. Any ideas of how to interface the RS-232 pin to a PIC 16F628 I/O pin?

A simple series resistor on any of the protected I/O pins - you can receive full RS232 data in that way as well. Check the circuit of the BASIC STAMP for an example.

 

[blueroomelectronics]

22K resistor would be enough to keep a PIC safe from a serial ports voltage output.

This old document might help
How To Receive RS-232 Serial Data

 

[sprntrcr]

Thanks guys, you've been a big help.