We will have voltage/current limiting on this pin, but I was thinking TTL level RTS. We'll be putting a spec on the port pins.
Wayne N6KR On Mar 5, 2012, at 12:58 PM, Oliver Dröse wrote: >> The advantage is that I could possibly pull out the RTS line from >> my one >> RS232 cable >> to the computer, and simply add it to the amplifier PTT plug in >> ACC2. I >> would not >> have to build a transistor switch to directly trigger the PTT line, >> which >> would have >> to be broken out from the custom MIC plug. > > Hi Lance, > > you should *NOT* apply RTS directly to the GPIO pin! RS-232 levels > go up > into the +/-20 volts region per specs and that would probably damage > the > microcontroller in the KX3 (at least this pin). Maybe Wayne can > shine some > light onto if GPIO is directly connected to the MC and thus can only > accept > 5 V or if there is something else in-between. > > Please don't be mistaken by that you can apply RTS directly at the K3 > because that has a level converter built in active also for RTS/DTR > pins > while the KX3 probably won't (see above). > > So an "interface" is needed anyway (1-transistor-interface), that's > why I > originally asked what the advantage of using GPIO for PTT would be > (besides > maybe easier cabling). > > A better solution might be to simply use VOX on DATA A then also for > WSJT > (just for easier cabling, I would still prefer "real" PTT on the mic > connector) and use GPIO's TX-INHIBIT functionality together with a > smallish > sequencer (could be built into the amp, too). Then you could be sure > that > the radio is not putting out any HF before all other equipment (PA, > pre-amp, > etc.) has switched and the TX-INH is unlocked. I am doing exactly > that on my > K3 ... and others, too. ;-)) > > Vy 73, Olli - DH8BQA > http://www.dh8bqa.de > > > > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
