FDC37B78X SMSC Corporation, FDC37B78X Datasheet - Page 170

• Manufacturer Part Number: FDC37B78X
• Description: Enhanced Super I/O Controller with ACPI Support/ Real Time Clock and Consumer IR
• Manufacturer: SMSC Corporation

Entering the Configuration State
The device enters the Configuration State when
the following Config Key is successfully written
to the CONFIG PORT.
When in configuration mode, all logical devices
function
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.
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.
initiation key is received correctly the chip enters
into the Configuration State (The auto Config
ports are enabled).
Config Key = < 0x55>
Config Key = < 0xAA>
properly.
Entering
and
Once the
exiting
170
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
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.
the
address
of
the
desired