-###3. V-USB connection
- +---+ +---------------+
- USB GND | | ATmega328p |
- ~~~ C3 | |
- 5V <-------+--------+---|Vcc,AVCC | HHKB pro pro2
- R1 | | ~~~~~~~~ ~~~~
- D- <----+--+-----R2-----|INT1 PB2-4|------->ROW (6-8) (5-7)
- D+ <----|---+----R3-----|INT0 PC0-2|------->COL (9-11) (8-10)
- Z1 Z2 | PC3|------->ENABLE (12) (11)
- GND<----+---+-----------|GND PB0|<-------KEY (4) (3)
- | PB1|------->PREV (5) (4)
- | |
- GND+-C2--+--|XTAL1 RXD|------->Debug Console
- X1 | TXD|<-------Debug Console
- GND+-C3--+--|XTAL2 RST|---SW--+GND
- +---------------+
- R1: 1.5K Ohm
- R2,R3: 68 Ohm
- Z1,Z2: Zener 3.6V
- C1,C2: 22pF
- C3: 0.1uF
- X1: Crystal 12MHz
- SW: Push Switch(for bootloader)
-
-- NOTE: See [V-USB] documentation for more detail of hardware and the USB stack.
-- NOTE: [USBaspLoader] is very useful for firmware update.