keyboard/hhkb_rn42/rn42/PowerSave.txt

   1 Power Saving
   2 ============
   3
   4
   5 MCU+HHKB Power Comsumption
   6 --------------------------
   7 Battery drive:
   8     idle    18.9mA
   9     active  35.8mA
  10
  11 USB powered:
  12     40.0mA
  13
  14
  15 HHKB key switch power control
  16 -----------------------------
  17 MOS FET Nch: BSS138 or IRLML6344T, either works and no apparent difference.
  18 Normally on(pull-up) or off(pull-down)? interms of power saving it prefers pull-down?
  19
  20 Pull-down will be better for power saving, normally off.
  21
  22
  23
  24 Used Timer
  25 ----------
  26
  27 8MHz clock
  28 ----------
  29 1) 16MHz xtal with system prescaler div2: F_CPU=8MHz, F_USB=16MHz
  30 2) 8MHz xtal with div1: F_CPU=8MHz, F_USB=8MHz
  31 Hardware USART doesn't work at 115200bps with 8MHz(F_CPU).
  32
  33 workaround:
  34 a) use Sotwre serial for communcation with RN-42
  35 b) reduce baud of RN-42 to lower rate;(factory default is 115200bps)
  36 10/03
  37
  38
  39
  40 Slave mode
  41 ----------
  42 Discovery/Inquire
  43 Connect/Page
  44
  45 SI,0012
  46 SJ,0012
  47 InqWindw=0100
  48 PagWindw=0100
  49
  50
  51 Sniff mode
  52 ----------
  53 0.625ms * <hex>
  54 SW,0320     Very sluggish. Type is not lost but very slow to register.
  55 SW,0160     Still sluggish. may transposed? can type but ...
  56             Mouse point move intermittently
  57 SW,0020     feel a bit late like stumble(20ms)
  58 SW,0010     feel no latency(10ms)
  59
  60
  61 Deep sleep
  62 ----------
  63 SW,8010
  64
  65
  66 TX power
  67 --------
  68 SY,fff4
  69
  70
  71 IO pins
  72 -------
  73 S%,1000         status led and connection control don't work
  74                 GPIO5: status LED
  75                 GPIO6: Connection control
  76                 GPIO2: linked status