VSC7173
Datasheet
F
UNCTIONAL
D
ESCRIPTIONS
Modes of Operation
summarizes the VSC7173 operational mode choices. The mode of the VSC7173 is determined by the
following pins.
MODE1:
Controls whether the selection of port 0 to port 1 is edge-sensitive or level-sensitive. When LOW, port
selection is level-sensitive (to enable level-sensitive port selection, pin PORTSEL1 must also be LOW). When HIGH,
port selection is edge-sensitive.
MODE0:
Controls the function of the unselected port. When LOW, the output of this port is turned off. When HIGH,
the output of this unselected port is the same data as seen on the selected port.
PORTSEL0:
In level-sensitive mode (MODE1 is LOW and PORTSEL1 is LOW), controls the selection of port 0 or
port 1. When LOW, port 0 is selected; when HIGH, port 1 is selected. In edge-sensitive mode (MODE1 is HIGH),
controls the selection of port 0; a rising edge on this pin selects port 0.
PORTSEL1:
In level-sensitive mode (MODE1 is LOW), must be held LOW. In edge-sensitive mode (MODE1 is
HIGH), controls the selection of port 1; a rising edge on this pin selects port 1.
Table 1. Port Selection Operating Modes
Input Pins
MODE1
0 (level)
0 (level)
0 (level)
0 (level)
1 (edge)
1 (edge)
1 (edge)
1 (edge)
X = don’t care;
↑
= rising.
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High-Speed Connections
PORTSEL1
0
0
0
0
↑
X
↑
X
P0OUT
P2IN
OFF
P2IN
P2IN
OFF
P2IN
P2IN
P2IN
P1OUT
OFF
P2IN
P2IN
P2IN
P2IN
OFF
P2IN
P2IN
P2OUT
P0IN
P1IN
P0IN
P1IN
P1IN
P0IN
P1IN
P0IN
0
1
0
1
X
↑
X
↑
MODE0
0
0
1
1
0
0
1
1
PORTSEL0
Status Pins
Two output pins, P0SLTD and OOBPORT0, are provided for status monitoring.
summarizes the functionality
of these two output pins. OOBPORT0 reports whether the signal on port 0 is above or below the threshold selected in
P0SLTD, depending on the state of MODE1, can either report which port is selected or can report whether
the signal on port 1 is above or below the threshold selected in
Table 2. Output Status Pins
Input Pins
MODE1
0 (level)
PORTSEL0
X
PORTSEL1
X
P0SLTD
OOB status port 1—1 indicates signal is
below OOB threshold, 0 indicates signal
is above OOB threshold
Indicates port selected, 0 = port 1
Indicates port selected, 1 = port 0
Output Status Pins
OOBPORT0
OOB status port 0—1 indicates signal
is below OOB threshold, 0 indicates
signal is above OOB threshold
OOB status port 0
OOB status port 0
1 (edge)
1 (edge)
X
↑
↑
X
X = don’t care;
↑
= rising.
4 of 17
VMDS-10121 Revision 4.1
May 23, 2005
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