FDC37B80X View Datasheet(PDF) - SMSC -> Microchip

Part Name

Description

Manufacturer

FDC37B80X

PC98/99 compliant enhanced super I/O controller with Keyboard / Mouse Wake-Up / 5 Volt Operation

SMSC -> Microchip 

UART Power Management

Direct power management is controlled by

CR22. Refer to CR22 for more information. Auto

Power Management is enabled by CR23-B4 and

B5. When set, these bits allow the following

auto power management operations:

1. The transmitter enters auto powerdown

when the transmit buffer and shift register

are empty.

2. The receiver enters powerdown when the

following conditions are all met:

A. Receive FIFO is empty

B. The receiver is waiting for a start bit.

Note:

While in powerdown the Ring Indicator

interrupt is still valid and transitions

when the RI input changes.

Exit Auto Powerdown

The transmitter exits powerdown on a write to

the XMIT buffer. The receiver exits auto

powerdown when RXDx changes state.

Parallel Port

Direct power management is controlled by

CR22. Refer to CR22 for more information.

Auto Power Management is enabled by CR23-

B3. When set, this bit allows the ECP or EPP

logical parallel port blocks to be placed into

powerdown when not being used.

The EPP logic is in powerdown under any of the

following conditions:

1. EPP is not enabled in the configuration

registers.

2. EPP is not selected through ecr while in

ECP mode.

The ECP logic is in powerdown under any of the

following conditions:

1. ECP is not enabled in the configuration

registers.

2 SPP, PS/2 Parallel port or EPP mode is

selected through ecr while in ECP mode.

Exit Auto Powerdown

The parallel port logic can change powerdown

modes when the ECP mode is changed through

the ecr register or when the parallel port mode is

changed through the configuration registers.

109

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