Power Saving
============


MCU+HHKB Power Comsumption
--------------------------
Battery drive:
    idle    18.9mA
    active  35.8mA

USB powered:
    40.0mA
    52mA    01/17

Other keyboards:
HHKB Pro    55mA
HHKB Pro2   140mA
HHKB Pro    42mA(Alt)
HHKB Pro2   52mA(Alt BT controller USB mode)
HHKB Pro2   88mA(Alt BT controller BT mode connected)
HHKB Pro2   68mA(Alt BT controller BT mode config mode)
Poker X     6mA
Infinity    24mA(TMK)
            65mA(kiibohd)


HHKB key switch power control
-----------------------------
MOS FET Nch: BSS138 or IRLML6344T, either works and no apparent difference.
Normally on(pull-up) or off(pull-down)? interms of power saving it prefers pull-down?

Pull-down will be better for power saving, normally off.



Used Timer
----------

8MHz clock
----------
1) 16MHz xtal with system prescaler div2: F_CPU=8MHz, F_USB=16MHz
2) 8MHz xtal with div1: F_CPU=8MHz, F_USB=8MHz
Hardware USART doesn't work at 115200bps with 8MHz(F_CPU).

workaround:
a) use Sotwre serial for communcation with RN-42
b) reduce baud of RN-42 to lower rate;(factory default is 115200bps)
10/03



Slave mode
----------
Discovery/Inquire
Connect/Page

SI,0012
SJ,0012
InqWindw=0100
PagWindw=0100


Sniff mode
----------
0.625ms * <hex>
SW,0320     Very sluggish. Type is not lost but very slow to register.
SW,0160     Still sluggish. may transposed? can type but ...
            Mouse point move intermittently
SW,0020     feel a bit late like stumble(20ms)
SW,0010     feel no latency(10ms)


Deep sleep
----------
SW,8010


TX power
--------
SY,fff4


IO pins
-------
S%,1000         status led and connection control don't work
                GPIO5: status LED
                GPIO6: Connection control
                GPIO2: linked status