Register map of IO_REG (base: 0x1000000)
========================================

  |   Offset   |   Name  |     Description      |
  |------------+---------+----------------------|
  | 0x00000000 | CTRL    | Control register     |
  | 0x00000004 | CONSOLE | Virtual console port |


CTRL Register (0x00000000)
--------------------------

  Control register

  | Bits | Name | Mode | Reset | Description |
  |------+------+------+-------+-------------|
  |    0 | STOP | WO   | 0     |             |


CONSOLE Register (0x00000004)
-----------------------------

  Virtual console port

  | Bits | Name  | Mode | Reset |           Description           |
  |------+-------+------+-------+---------------------------------|
  |    9 | VALID | RO   | 0     | Symbol in DATA is valid         |
  |    8 | SEND  | HS   | 0     | Write 1 to send symbol          |
  |  7:0 | DATA  | RW   | 0     | Read/write char from/to console |