RS232 FORCE_SW, INVERT

[Barney]

I using a 16F88 for RS232 comms on a PC and am developing the code on a PICDEM4. The PICDEM4 connects RB2 & RB5 from the 16F88 USART to a 9 pin connector thru a level conversion chip. Makes RS-232 easy.

My eventual target is a small PCBA powered by +12v from the RS232 and I want to save milliamps by not having a RS232 level converter so I have to invert the bits.

For development on the PICDEM4 I am using the H/W USART and the following statement: #use rs232(BAUD=19200, XMIT=PIN_B5, RCV=PIN_B2, PARITY=N, BITS=8) and it works fine.

I am ready switch to the RS-232 powerd PCBA and since it does not have an inverter used the FORCE_SW and INVERT options. #use rs232(FORCE_SW, INVERT, BAUD=19200, XMIT=PIN_B5, RCV=PIN_B2, PARITY=N, BITS=8).

I tried it on the PICDEM4, expecting the RS232 comms to not work because of the inversion. To my surpise it still works fine. This tells me the INVERT is not working correctly. Any suggestions?

Thanks
Barney

[asmallri]

Have a look at the .lst file and see what it is doing.
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Regards, Andrew

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[Barney]

Good suggestion. I looked at the list file and it did not show the FORCE_SW & INVERT in the #use RS232. I still have no idea how, but I was editing the wrong file. I made the change to the file I was downloading and it worked OK.

Thanks