Hi guys,
I custom built a UBW, and wondering whether I should wire my 315 Mhz RF modules (both on Rx and Tx) directly for direct UART communications or should I use RS232 chips to utilize Manchester modulation? Which would be better?
Depending on the modules and I'm assuming these are dumb radio modules then you use some type of balanced encoding, it doesn't have to be Manchester, but it can be.
You do not use the UART and you do not use RS232 level shifting IC's.
What the transmitter 'sees' on its data pin is what the receiver outputs on its data pin. If you can configure the UART module on a PIC, you have an instant wireless data connection.
Those modules don't like the UART for multiple reasons. 1. UART control signals are backwards, carrier is always on; 2. UART signals are edge triggered; 3. UART signals cannot be fully balanced even with encoding, due to the carrier and control bits.