PTT CAT control using USB Arduino Nano Every

Mick W8BE · March 25

I had developed a CAT control interface utilizing a USB Arduino Nano Every and I had issues with stability. Last week I operated in the VA QSO party and used the PTT SmartCAT interface with my foot switch. It is a Linemaster industrial foot switch and the bounce effect when using the switch was very noticeable. This got me thinking about my CAT control interface. I went back and used Wireshark to examine my FlexControl. I noticed the commands were sent very quickly to the radio. I had the Arduino Nano Every set to 9600 baud. I decided to change the baud and after experimenting I was able to get the device to act in a stable manor. I have updated the repository. I find using the CAT control is very quiet and so far I have had no stability issues Here is the link to the repository.

https://github.com/w8be/usb-ptt-arduino-nano-every/tree/main

KD0RC · March 25

Very cool Mick. One trick that I use is to attach an interrupt to the input pin. In the ISR, I immediately disable that interrupt, service the interrupt, and set a timer (20 ms or whatever I need to get past the bouncing). When the timer expires, I enable the interrupt again. This makes sure that I get the earliest possible "make" contact and that additional bounces don't chatter relays and that kind of thing.

For this scheme, I usually attach the interrupt using CHANGE so that I can use the same technique on the break. I often wind up with a different break timeout than make timeout. It mostly depends on the switch and how fast I want to be able to cycle it. PTT will usually have longer time constants than a dot paddle, for example.

Mick W8BE · March 25

Thanks Len,

I am including a bounce function from the libraries. I currently have the bounce timer set to 200ms.

Regards

Mick W8BE · March 25

Here are a couple pics.

KD0RC · March 25

Very clean installation!

Mick W8BE · March 26

Ken,

Can you share your ISR code. It may very well be worth switch too.

Thanks

KD0RC · March 27

Hi Mick, The full source for my TeensyMaestro is out on GitHub. With everything going on, it will be a challenge to filter out what you need.

Here is a real quick sample:

/*
  Sample Interrupt-driven input
  Len Koppl, KDØRC 
  03/26/24 
  Teensy 4.1(with built - in Ethernet)

*/
// Includes

// Constants
const byte BUTTON_PIN = 0;
const int DEBOUNCE = 20;  // debounce time in ms

// Global Variables
IntervalTimer debounceTimer;

void setup()
{
  attachInterrupt(digitalPinToInterrupt(BUTTON_PIN), buttonISR, FALLING);
}

void loop()
{
  // looping code here
}

// Subroutines

// Interrupt Service Routines
void buttonISR()
{
  detachInterrupt(BUTTON_PIN);  // stop button interrupt to prevent multiple hits (bounce)
  // quick stuff here like setting a variable.  Do not do massive processing in the interrupt service routine.

  debounceTimer.begin(debounceISR, DEBOUNCE);
}

void debounceISR()
{
  debounceTimer.end();
  attachInterrupt(digitalPinToInterrupt(BUTTON_PIN), buttonISR, FALLING); // allow button pushes again after debounce period
}

Hopefully, this helps.

KD0RC · March 27

Well, I'm an idiot... That sample code is for a Teensy 4.1, not a Nano Every. If I get a chance, I will see if there is a timer library for the Nano Every. If not, then it might not be worth the effort to do what I am suggesting.

Mick W8BE · March 27

Thanks...no rush

PTT CAT control using USB Arduino Nano Every

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