FDC37N958FR Ver la hoja de datos (PDF) - SMSC -> Microchip

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FDC37N958FR

Notebook I/O Controller with Enhanced Keyboard and System Control

SMSC -> Microchip 

Table 5 - State of System Pins in FDC Auto Powerdown

SYSTEM PINS

STATE IN AUTO POWERDOWN

Input Pins

nIOR

Unchanged

nIOW

Unchanged

AEN

Unchanged

nMEMRD

Unchanged

nMEMWR

Unchanged

SA[15:0]

Unchanged

SD[7:0]

Unchanged

nNOWS

Unchanged(hi-Z)

nDACKx

Unchanged

TC

Unchanged

nROMCS

Unchanged

Output Pins

RESET_OUT

Unchanged

IRQx

Unchanged(low)

DB[0:7]

Unchanged

DRQx

Unchanged(low)

IOCHRDY

Unchange(n/a)

FDD Interface Pins

All pins in the FDD interface which can be

connected directly to the floppy disk drive itself are

either DISABLED or TRISTATED. Pins used for

local logic control or part programming are

unaffected. Table 6 depicts the state of the floppy

disk drive interface pins in the powerdown state.

FDD Power Down Pin (FPD) Behavior

The FPD pin can be used to automatically shut

off power to the floppy disk drive when it is not

required. The FPD pin is an active high output

signal which is driven based on the states of the

FDC. Whenever the FDC Shutdown bit is set

(see FDD Mode Register, bit-5 in the

Configuration Register Section) the FPD pin

goes high. If the FDC Shutdown bit is not set

then the FPD pin will go high whenever the FDC

bit (see bit 0 of the Power Mgmt Register in the

Configuration Section) is set and the FDC has

entered an auto powerdown state as described

above. If neither the FDC Shutdown bit nor the

FDC bit are set then the FPD pin goes active

“high” when the Power- down bit is set (see bit 6

of the Data Rate Select Register [DSR]) and

“low” when the Powerdown bit is cleared. Refer

to Table 6A.

SMSC DS – FDC37N958FR

Page 20

Rev. 09/01/99

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