User guide

Channel B is uncommitted and uninitialized by system ﬁrmware.

For more information about these serial lines, see Chapter 2.

9.4.2 Super I/O Register Address Space

CPU Address: 0x1C0003E00 - 0x1C0007FE0

Nbus offset: 0x01F0 - 0x03FF

Table 9–10 lists the base address values for the serial port and parallel port

controller.

The general registers are located at addresses 398 (index address) and 399 (data

address). For example, writing an index value of 1 to address 398 selects the

function address register. If a read transaction from address 399 follows, the data

associated with the function address register is returned. If a write transaction

to address 399 follows, the function address register is updated.

Table 9–10 Super I/O Register Address Space Map

Address Offset

Read/Write

Physical

Address Register

General Registers

398 1 C000 7300 Index address register

399 1 C000 7320 Data address register

Index Register

0 Function enable register

1 Function address register

2 Power and test register

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Nbus 9–19