TrxAVR-Picastar Useful facts and hints
Programming - setting 
  fuses
  - see:  TrxAVR_Picastar 
  setup instructions - 3 - Atmega2560 programming
When 
  setting fuses, do not set SUT_CKSEL to an external option. 
  In-situ programming needs 
  the clock to be running. The ATmega2560 is supplied with
  the internal R/C clock oscillator selected - so you can program it. Switching 
  to internal
  oscillator using the 16Mhz crystal allows you to program it.  BUT - if 
  you select a 
  non-existent external clock source, then you thereafter have no clock and so 
  you are
  effectively locked out. ie: you cant program the chip and so so can't change 
  back to a
  working clock option. To recover from this sitiuation you need to apply an external 
  clock
  signal (eg: from the other ATmega2560 using a piece of wire and a capacitor!)
TrxAVR construction 
  - minimum configuration to allow early testing
      see: Minimum 
  configuration
DDS Commands:
DDS23 Toggles PortA bit 0
DDS26 Toggles the DSP 
  and DDS help displays:
  The sequence is: nil  >   DDS 
  help  >  DSP help  > 
   DDS and DPS help 
   >  nil    etc
  (DSP help is on the screen in the resting state. DDS help occurs after a long 
  key press.)
  The selection is stored in internal EEMEM / trxavreemem.ini
DDS78 Toggles 
  key value display. ( off > key code > matrix column )
  If this is on, then the key code of a key press is briefly displayed on the 
  screen.
  This is very useful in setting up the keypad.
  If your keyboard isn't working yet, then you can activate the key code display, 
  by setting
  DisplayKeyValue=0 in trxavreemem.ini and then 
  using load EEMEM to load to TrxAVR. 
Memory stack slot 
  buttons.
  Refer to Picastar manual.
Button tasks:
      Memory stack 67 sets the current memory 
  stack to 67 (of 67, 68, 69, 60)
      Memory slot 61 set load slot 61 
  from the current memory stack.
        (same action as DDS61)
      Mem stack tune 67 sets the current 
  memory stack to 67 loads slot 67:61
         and enters memory stack tuning mode (same 
  action as DDS67)
Soft keys labelling
  TrxAVR-Picastar allows you 
  to assign tasks to:
See Keypads and buttons for more information
Shift key and encoder assignment
If the S(hift) key is 
  pressed, then provided no other key is pressed in the next 5 seconds,
  the twiddling of an encoder will bring up the encoder assignment menu for that 
  encoder. 
  You can, if you wish, in the usual way use the menu encoder to the assign the 
  required function
  BUT in fact the encoder you twiddled can be used to select a parameter for assignment 
  to
  itself. M(enu) will save the change and E(scape) or “#” will exit.
  So encoder assignment is simplified to pressing shift and then twiddling the 
  encoder you want
  to assign to and then pressing menu to save the assignment.
Encoder assign button
Encoder assign 
  is a button task than can be assigned to a button or touchpad.
  When you press it, it brings up the 
  encoder assignment menu for the last encoder to have been
  assigned (or encoder 1 if no assignments have been made since startup). 
  Turning that encoder moves through the parameter assignment list to select a 
  parameter for itself.
  Pressing the last encoder button again saves the current parameter selection 
  to the encoder.
  (ie it has the function of the menu button)
  At first sight this seems to do nothing much different to the Shift key encoder 
  assignment described above.
The intended application is that one encoder 
  (preferably Encoder 1) is an encoder with a push switch.
  This push switch is connected into the key matrix and has a Rx button assignment 
  as Encoder assign.
  This now means that Encoder 1 has its own 'Shift' and 'Menu' key functionality.
  Pushing in the encoder will bring up the encoder's 
  parameter assignment menu. Twiddling it will select a
  parameter and then pushing it in again will save that parameter to it.
  So this is a fast way to assign a parameter to Encoder 1 .... without taking 
  you fingers off it.
  I may be of use in rig where the builder has chosen to have only a small number 
  of encoders.