keyboard/hhkb/iwrap.txt

   1
   2 iWRAP
   3 -----
   4                         +---------------+        WT12
   5               5V        |   ATmega168   | 5V/3.3V~~~~
   6               +-----+---|Vcc,AVCC    PC4|---/--->iWRAP(RxD)
   7 USB           |     C3  |            PC5|<--/----iWRAP(TxD)
   8 ~~~           |     +   |               |
   9 5V <--BATT    +    GND  |               |        HHKB
  10               R1        |               |        ~~~~
  11 D- <----+-----+--R2-----|INT1      PB2-4|------->ROW(6-8)
  12 D+ <----|---+----R3-----|INT0      PC0-2|------->COL(9-11)
  13         Z1  Z2          |            PC3|------->ENABLE(12)
  14 GND<----+---+-----------|GND         PB0|<-------KEY(4)
  15                         |            PB1|------->PREV(5)
  16                         |               |
  17             GND+-C2--+--|XTAL1       RXD|------->Debug Console
  18                      X1 |            TXD|<-------Debug Console
  19             GND+-C3--+--|XTAL2       RST|---SW--+GND
  20                         +---------------+
  21
  22 R1:     1.5K Ohm
  23 R2,R3:  68 Ohm
  24 Z1,Z2:  Zener 3.6V
  25 C1,C2:  22pF
  26 C3:     0.1uF
  27 X1:     Crystal 12MHz
  28 SW:     Push Switch(Optional)
  29 BATT:   Li-Po Battery, Battery Charger and Voltage Regulator(5V and 3.3V).
  30
  31
  32