Proton PICBASIC vs MeLabs PICBASIC

[tenaja]

Full-duplex software UART is not possible or possible only if the baud rate is very low and interrupts are used. (Software UARTs use bit-banging).

It could be done if you send and receive in the interrupt. Set it to interrupt at 2*baud, and alternate Tx/Rx. At 9600 baud, with 19200kHz interrupt rate on a 20MHz crystal, you get 260 code cycles to perform each...that should be more than enough, and cycles left over for other regular code. You might even get close to that rate with a 4MHz crystal if you are thrifty with your code.

Or, in the interrupt do the Tx send first, then all Rx work, then Tx setup for the next bit, without alternating, so the "Tx send" portion is actually very short and always the same length. This might be more efficient, but maybe a little more coding.