FT817 external display, revised

The external display firmware for ATmega48/88/168 chips is ready for a public beta.

I have kept a two-button user control interface and changed the LO programming method.

Since the survey (and following emails) showed that it is possible to have 100 Hz accuracy on 47 GHz transverters (WOW!), the display now allows 0.1 kHz resolution both for LO and VFO.
The LO value, 16 values actually, are inserted digit-by-digit through the two buttons when in "config mode".

Updated characteristics are:

• based on ATmega48/88/168 chip clocked at 11.052 MHz
• 2*16 character display (HD44780)
• 2 buttons interaction
• "config" and "normal" operation modes
  
• 16 LO values stored in EEPROM (survive poweroff, can be fewer)
  
• LO value down to 100 Hz
• LO ranges from 0 to 214'748'364'700 Hz (that's 214.7 GHz)
• VFO/output frequency computed to 100 Hz resolution
• support for both Out= LO+IF and Out=LO-IF
• LO value selection by button press (1 > 2 > ... > 15 > 16 > 1 > ...)
• VFO A/B toggle on second button
  

The "config mode" is accessed at display powerup by pressing a button. Reboot the display to enter normal operation mode.

I am working on a circuit diagram to be published soon. Who built the ATtiny2313-based display can assemble a simple adapter board for ATmega chips.