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Serial communication without rs233/rs232?

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I don't know, what you want, but is posibily serial

comunication using hardware or software implementation

PIC to PIC, I was working with a PIC16F877 link a

PIC16F84 directly without any external hardware





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I have seen a circuit that connects the PC serial port to PIC with a 22K ohms direct connect, and the author claims that it works. I am going to try that. ()

Becareful. The circuit you are talking about will almost certaininly not being meeting the RS232 specification, although it may work on one PC.


The RS232 spec requires a minimum of +/-3V at the receiver, so if you want your PC to receive data from you PIC you need to provide voltages at least around these levels.


If you just want your pic to recieve data from you PC, then a couple of resistors and clamping diodes should work pretty well, but the interace does not meet the RS232 spec.


Something like a max232 does a nice solution to providing at interface that meets the RS232 spec.


Another thing to bear in mind is that different PC manufactures RS232 ports vary. So an out of specification designed that works with one PC may not work with another.


If you are really interested there are pages on the web (sorry cant remember where) about designing micro-power circuits that interface to the RS232 port and get all their power from there two (a normal mouse does this), but these designs have to be very clever to work with all PC's.


Have Fun





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