97CFDC Datasheet, PDF (10/20 Pages) SMSC Corporation – USB FLOPPY DISK CONTROLLER

BUFFER TYPE DESCRIPTIONS
Table 1 - USB97CFDC Buffer Type Descriptions
BUFFER
DESCRIPTION
I
Input
IS
Input with Schmitt trigger
O8
Output with 8mA drive
I/O8
Input/output with 8mA drive
OD12
Open drain….12mA sink
O24
Output with 24mA drive
OD24
Open drain….24mA sink
ICLKx XTAL clock input
OCLKx XTAL clock output
I/O-U
See Table 6.
BOARD TEST MODE OPERATION
By driving the nTESTEN pin low, the device will be placed into a special test mode to allow verification of attachment
of the device to the circuit board. Every pin except the TSTOUT, XTAL2, and the power and ground pins become an
input to an XNOR chain, as shown below, to allow continuity to be tested on the board. This test should individually
toggle the state of the trace connected to the pin being examined for continuity, and the TSTOUT pin monitored for
toggle of state. If no toggle occurs, either the pin under test is discontinuous, or the TSTOUT pin is not connected on
the board
Pin1
Pin2
Pin3
Pin100
TSTOUT
SMSC DS – USB97CFDC
Page 10
Rev. 12/15/2000