FDC37B78X View Datasheet(PDF) - SMSC -> Microchip

Part Name

Description

Manufacturer

FDC37B78X

Enhanced Super I/O Controller with ACPI Support, Real Time Clock and Consumer IR

SMSC -> Microchip 

Entering the Configuration State

The device enters the Configuration State when

the following Config Key is successfully written

to the CONFIG PORT.

Config Key = < 0x55>

When in configuration mode, all logical devices

function properly. Entering and exiting

configuration mode has no effect on the devices.

Exiting the Configuration State

The device exits the Configuration State when

the following Config Key is successfully written

to the CONFIG PORT.

Config Key = < 0xAA>

CONFIGURATION SEQUENCE

To program the configuration registers, the

following sequence must be followed:

1. Enter Configuration Mode

2. Configure the Configuration Registers

3. Exit Configuration Mode.

Enter Configuration Mode

To place the chip into the Configuration State

the Config Key is sent to the chip's CONFIG

PORT. The config key consists of a write of

0x55 data to the CONFIG PORT. Once the

initiation key is received correctly the chip enters

into the Configuration State (The auto Config

ports are enabled).

Configuration Mode

The system sets the logical device information

and activates desired logical devices through

the INDEX and DATA ports. In configuration

mode, the INDEX PORT is located at the

CONFIG PORT address and the DATA PORT is

at INDEX PORT address + 1.

The desired configuration registers are accessed

in two steps:

a. Write the index of the Logical Device

Number Configuration Register (i.e., 0x07) to

the INDEX PORT and then write the number of

the desired logical device to the DATA PORT.

b. Write the address of the desired

configuration register within the logical device to

the INDEX PORT and then write or read the

configuration register through the DATA PORT.

Note: if accessing the Global Configuration

Registers, step (a) is not required.

Exit Configuration Mode

To exit the Configuration State the system writes

0xAA to the CONFIG PORT. The chip returns

to the RUN State.

Note: Only two states are defined (Run and

Configuration). In the Run State the chip will

always be ready to enter the Configuration

State.

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