Is it possible (using one of Sparkfun’s modems) to have simultaneous communication on both the Tx and the Rx pins? I’d like to have the Parallax Propeller dedicate two cogs, one for each pin.
If it’s not possible with this modem, would something else work? Or am I just going to have to make the network wait?
Which one specifically?
In general, you can’t go full duplex over the air on the same frequency. You can emulate it using TDMA, or just use two separate frequencies and two transceivers at either end.
I was looking at the HAC-LN96. I looked up TDMA on Wikipedia, and it seems rather difficult if the times are not matched precisely. Two transcievers per station seems expensive (at $90 a piece). So, I guess the problem lies in the very fact that it’s a transciever. If I had two seperate modules, one a transmitter and one reciever, the system would work (each on a different channel). Any thoughts? Mostly for my system, I’d rather not have to worry about timing between the nodes. Idealy, they just send data whenever they have to, without worrying about waiting for stuff to come in.
Don’t have direct experience with that module, but from the datasheet it appears to have flow control features built in. As long as you’re not depending on 9600 bps in both directions, it should handle the clear channel assessment for you and allow interleaved half-duplex mode.
If you can stand lower range, the Nordic nRF24L01 modules are very nice.
I don’t know any of the EE stuff or signals theory, so I’ll ask: won’t the incoming signals mess with the outgoing (since they’re on the same antena) and so ruin both readings?