HHKB Power consumption ---------------------- **Power consumption board clock/prescaler keyswitch power ctrl current -------------------------------------------------------------------------- tmk 16MHz no no 26.4mA tmk 16MHz pro1 no 45.1mA tmk 16MHz/2 no no 18.1mA tmk 16MHz/2 pro1 no 37.3mA tmk 8MHz no no 18.9mA tmk 8MHz pro2 no(w/o FET) 32.1mA tmk 8MHz pro2 no(w FET) 32.1mA withou POWER_ON/FF tmk 8MHz pro2 no(w FET) 32.6mA with POWR_ON/OFF tmk 8MHz pro2 15ms(w FET) 21.3mA with POWR_ON/OFF, enumerated but error -32 tmk 8MHz pro2 60ms(w FET) 13.3mA with POWR_ON/OFF, not enumerated gh60 16MHz 25.8mA gh60 16MHz USB suspend w LED breathing 17.6-29.1mA gh60 16MHz USB suspend w/o LED 0.2mA(0.231-0.276mA) Poker 5.6mA Poker USB suspend 0.3mA(0.301mA) gh60 16MHz stock firmware by komar 26.8mA HHKB pro2 Over All 139.4mA HHKB pro2 Controller 115.1mA HHKB pro1 Controller 25.9mA keyswitch power consumption: pro1: 45.1-26.4=18.7mA 37.3-18.1=19.2mA pro2: 32.1-18.9=13.2mA **Low Freq Crystal or Prescaler? No advantage of Low Freq Crystal against Prescaled. Clock routing X'tal --+---->Prescaler-------> System Clock | +---------------------> USB PLL Design Decision: Install 16MHz crystal on board with using clock rescaler.