Significant updates. Compiles and works, though not test significantly nor assumed to be particularly robust. I2C comms between Raduino and TeensyDSP. Some amount of functioning CAT. Haven't tried with any applications e.g. WSJT-X.

Raduino/ubitx_menu.ino

@@ -263,7 +263,7 @@ void menuCHMemory(int btn, byte isMemoryToVfo){
         }
       }
 
-      Check_Cat(0);  //To prevent disconnections
+      //Check_Cat(0);  //To prevent disconnections
     } //end of while (knob)
 
     if (selectChannel < 20 && selectChannel >= 0)
@@ -697,7 +697,7 @@ int getValueByKnob(int valueType, int targetValue, int minKnobValue, int maxKnob
         }
       }
 
-      Check_Cat(0);  //To prevent disconnections
+      //Check_Cat(0);  //To prevent disconnections
     }
 
     return targetValue;
@@ -1290,7 +1290,7 @@ void doMenu(){
       default :
         menuExit(btnState);  break;
     } //end of switch
-    Check_Cat(0);  //To prevent disconnections
+    //Check_Cat(0);  //To prevent disconnections
   }   //end of while
 
   //****************************************************************************
@@ -1690,7 +1690,7 @@ void menuSetupCarrier(int btn){
     si5351bx_setfreq(0, usbCarrier);
     printCarrierFreq(usbCarrier);
 
-    Check_Cat(0);  //To prevent disconnections
+    //Check_Cat(0);  //To prevent disconnections
     delay(100);
   }