FT817 external display architecture

ATtiny or ATmega for the External Display? This is the question!

After I have fought with the tiny2313 to fit all requested features for the external display (for transverters), and lost ... after I have searched up and down the Net for the ATtiny4313 PDIP and realized that it is probably not yet in production ... I gave up.

The choice was whether to maintain backward compatibility with the stand-alone keypad based on ATtiny2313 OR establish a new standard, compatible with the "remote control" to-be.

While the ATmega chip can cost 3 times the ATtiny uC, it gives me much more freedom to produce something not only satisfactory, but fitting all the requirements. And leaves headroom for future extensions. Moreover a PCB drawn and produced for the display can be done for the keypad+display at the same time, just leave out components when assemblying.

So, ATmega48/88/168 is the final choice. Probably an ATmega48 will suffice.

In any case I will not throw away the ATtiny2313 external display firmware for those who have built the circuit published in the last month (October 2010). It will be available on request.


In any case the 2*16 LCD display based on HD44780 controller will not change.