FDC37C672 View Datasheet(PDF) - SMSC -> Microchip

Part Name

Description

Manufacturer

FDC37C672

Enhanced Super I/O Controller with Fast IR

SMSC -> Microchip 

Enhanced Super I/O Controller with Fast IR

Datasheet

Chapter 19 Configuration

The Configuration of the FDC37C672 is very flexible and is based on the configuration architecture

implemented in typical Plug-and-Play components. The FDC37C672 is designed for motherboard

applications in which the resources required by their components are known. With its flexible resource

allocation architecture, the FDC37C672 allows the BIOS to assign resources at POST.

19.1 System Elements

19.1.1 Primary Configuration Address Decoder

After a hard reset (RESET_DRV pin asserted) or Vcc Power On Reset the FDC37C672 is in the Run

Mode with all logical devices disabled. The logical devices may be configured through two standard

Configuration I/O Ports (INDEX and DATA) by placing the FDC37C672 into Configuration Mode. The

BIOS uses these configuration ports to initialize the logical devices at POST. The INDEX and DATA ports

are only valid when the FDC37C672 is in Configuration Mode.

The SYSOPT pin is latched on the falling edge of the RESET_DRV or on Vcc Power On Reset to

determine the configuration register's base address. The SYSOPT pin is used to select the CONFIG

PORT's I/O address at power-up. Once powered up the configuration port base address can be changed

through configuration registers CR26 and CR27. The SYSOPT pin is a hardware configuration pin

which is shared with the nRTS1 signal on pin 87. During reset this pin is a weak active low signal which

sinks 30µA.

Note: All I/O addresses are qualified with AEN.

The INDEX and DATA ports are effective only when the chip is in the Configuration State.

PORT NAME

CONFIG PORT (Note 19.2)

INDEX PORT (Note 19.2)

DATA PORT

SYSOPT= 0

(PULL-DOWN RESISTOR)

REFER TO Note 19.1

0x03F0

0x03F0

INDEX PORT + 1

SYSOPT= 1

(10K PULL-UP RESISTOR)

0x0370

0x0370

TYPE

Write

Read/Write

Read/Write

Note 19.1 If using TTL RS232 drivers use 1K pull-down. If using CMOS RS232 drivers use 10K pull-down.

Note 19.2 The configuration port base address can be relocated through CR26 and CR27.

19.1.2 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 >

SMSC FDC37C672

Page 121

DATASHEET

Rev. 10-29-03

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