SIO10N268 Datasheet, PDF (161/251 Pages) SMSC Corporation – Advenced Notebook I/O for ISA or LPC Designs with X-Bus Interface for I/O, Memory, and FWH Emulation and Four Srial Ports

Advanced Notebook I/O for ISA or LPC Designs
Datasheet
Chapter 10 Configuration
The configuration of the SIO10N268 is programmed through hardware selectable Configuration Access
Ports that appear when the chip is placed into the configuration state. The SIO10N268 logical device
blocks, if enabled, will operate normally in the configuration state.
10.1 Configuration Access Ports
The Configuration Access Ports are the CONFIG PORT, the INDEX PORT, and the DATA PORT (Table
10.1). The base address of these registers is controlled by the nRTS1/SYSOPT pin and by the
Configuration Port Base Address registers CR12 and CR13. To determine the configuration base address
at power-up, the state of the nRTS1/SYSOPT pin is latched by the trailing edge of a hardware reset
(deasserting edge of PCI_RESET#). If the latched state is a 0, the base address of the Configuration
Access Ports is located at address 0x02E; if the latched state is a 1, the base address is located at
address 0x04E. The base address is relocatable via CR12 and CR13.
Table 10.1 - Configuration Access Ports
PORT NAME
CONFIG PORT
INDEX PORT
DATA PORT
SYSOPT = 0
SYSOPT = 1
0x02E
0x04E
0x02E
0x04E
INDEX PORT + 1
TYPE
WRITE
READ/WRITE (Note 10.1, Note 10.2)
READ/WRITE (Note 10.1)
Note 10.1 The INDEX and DATA ports are active only when the SIO10N268 is in the configuration state.
Note 10.2 The INDEX PORT is only readable in the configuration state.
10.2 Configuration State
The configuration registers are used to select programmable chip options. The SIO10N268 operates in
two possible states: the run state and the configuration state. After power up by default the chip is in the
run state. To program the configuration registers, the configuration state must be explicitly enabled.
Programming the configuration registers typically follows this sequence:
1) Enter the Configuration State,
2) Program the Configuration Register(s),
3) Exit the Configuration State.
10.2.1 Entering the Configuration State
To enter the configuration state write the Configuration Access Key to the CONFIG PORT. The
Configuration Access Key is one byte of 55H data. The SIO10N268 will automatically activate the
Configuration Access Ports following this procedure.
10.2.2 Configuration Register Programming
The SIO10N268 contains configuration registers CR00-CR54. After the SIO10N268 enters the
configuration state, configuration registers can be programmed by first writing the register index number
(00 - 54H) to the Configuration Select Register (CSR) through the INDEX PORT and then writing or
SMSC SIO10N268
Page 163
DATASHEET
Rev. 0.5 (03-24-05)