GPIO state change during TX

[sp6hfe]

Hi All,

I am building my 1st QO-100 station and I designed it in a way that the PA's power is going through a relay.
I am interested in where to look in the Remote SDR's  code in order to inject dedicated RPI's GPIO voltage level change when TX is ongoing.
What I want to achieve is to cut-off PA's power when there is no transmission in Remote SDR.

Other option would be to add a toggle switch somewhere on GUI to change the state of a dedicated GPIO. With that I would arm TX path with power when I plan to transmit.

3rd option would be to use PWM output from RPI. With a bit of filtering on the relay side I would turn the relay on only when certain PWM signal would appear. That would prevent reacion on voltage steady states.

If anyone has any idea please drop here a line or two.

Thanks!
73

[F1ATB]

This fonction is implemented already. Look here on security chapter, https://search.app?link=https%3A%2F%2Ff1atb.fr%2Fqo-100-transceiver%2F&utm_campaign=aga&utm_source=agsadl2%2Csh%2Fx%2Fgs%2Fm2%2F4

[sp6hfe]

Hello Andre,

actually I have overlooked that description on your website.
My question would be: is GPIO level being toggled when audio rx is enabled?
And at the same time: is GPIO number configurable on RPI4?

Thanks!
73

[F1ATB]

https://f1atb.fr/qo-100-transceiver/

The GPIO 26 is toggled only during TX audio transmission.
In the code you can modify the GPIO number.

André

[sp6hfe]

Andre,

what is the frequency of the GPIO toggling and which file is responsible for toggling GPIO definition?
Many thanks!

73

[F1ATB]

Around 50Hz If I correctly remember. Ther is no file, it's each time data from your microphone is received.
André
F1ATB

[sp6hfe]

Andre,

you have said: "In the code you can modify the GPIO number" so I am interested in which file it is defined?

[sp6hfe]

Andre,

I have discovered GPIOS are settable on the Settings page of Remote SDR. Wasn't that so intuitive for me but after checking your YouTube videos I have understood where and how to configure.

Regarding GPIO that should be turning on a relay delivering power to the PA do I understand it correct that this one is not settable in Settings under GPIO section either in Rx Configuration or Tx Configuration? As written in both sections "NumGPIO 7 or pin 26 reserved for Transmit security Oscillator" meaning it can't be used because this is the one toggling automatically on every 256B of received audio data?

Thanks for confirmation.

[F1ATB]

Yes confirmed. Fixed GPIO number.
André