USB97CFDC2-01 datasheet(10/24 Pages) SMSC

10 / 24 page

SMSC DS – USB97CFDC2-01

Page 10

Rev. 02-27-07

DATASHEET

PIN NO.

NAME

SYMBOL

BUFFER

TYPE

DESCRIPTION

Crystal Output XTAL2

OCLKx

14.318Mhz Crystal

This is the other terminal of the crystal, or left open

when an external clock source is used to drive

XTAL1/CLKIN.

It may not be used to drive any

external circuitry other than the crystal circuit.

ROM Enable ROMEN

If this input is tied high or left open, the internal

program ROM is enabled. If tied low, external

program

memory

can

used

for

custom

applications.

Drive Density

Output

HDO

In some configurations of the USB97CFDC, this

drive pin indicates if a 640/720K disk is inserted in

the drive. Polarity of this signal is determined by

the configuration selected by the OPT[3:0] pins at

reset. If this pin is not driven by the drive, it should

be tied low.

Drive Ready

nDRVRDY

An active low signal on this pin from the floppy disk

drive, after DS0 goes active, indicates that the

system may activate MTR0. If the drive does not

supply this signal, this pin should be tied low.

Drive Power

nFDPWR

OD24

This active low signal is intended to activate an

external power switch, either in the drive or on the

system board, to supply power to the floppy disk

drive. It is active whenever the USB97CFDC2-01

is not in SUSPEND mode.

RESET input

nRESET

This active low signal is used by the system to

reset the chip. The active low pulse should be at

least 100ns wide.

Test output

TSTOUT

This signal is used for testing the chip via an

internal XNOR chain. User should normally leave it

unconnected.

Test input

nTEST

This signal is a manufacturing test pin. It should

be tied to VDD for normal operation.

Test Enable

nTESTEN

This active low signal places the device into board

test mode using the XNOR chain. For normal

operation this pin should be tied high. See Board

Test Mode Operation on page 14

POWER, GROUND, AND NO CONNECTS

14, 39, 60,

82, 93

VDD

+3.3V power

8, 19, 27, 43,

52, 66, 79,

81, 88

GND

Ground Reference

1-7, 9-13, 23,

51, 78, 80,

83-87, 89-92,

94-100

No Connect. These pins should not be connected

externally.

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