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I'm working on a weak signal station and would like to switch TX and RX lines based on a PTT signal. Is there something on the board that would indicate when TX switches to/from activated? If so, how do I access that signal?

I am writing the software, so to speak, using gnuradio companion. So while I am controlling TX / RX switching, I'm not aware of any interface in GRC to control GPIO pins. I suppose I'll need to roll my own software to get the functionality I'm looking for unless I overlooked some binding in GRC to control the BladeRF's GPIO pins.

I'm looking into adding GPIO support to gr-osmosdr but have to admit I'm starting from ground zero in terms of familiarity with programming for GRC (I'm a programmer by day, so I'm not starting from zero). Any pointers to where to look would be helpful.