Advance Product Information
Subject to Change
VSC7111 Datasheet
Functional Descriptions
important to ensure that the SCK pin is properly connected. In static configuration
mode, the SCK pin should be tied high or low. In the programming mode, SCK must be
free to toggle high and low under control of the programming interface.
When MUXCFG = 0 in static configuration (buffer mode), SCK = 0 disables automatic
PCIe receiver detect, and SCK = 1 enables automatic PCIe receiver detect. When
MUXCFG = 1 (MUX/fanout mode), SCK = 0 or 1 determines which two of the inputs
become primary inputs for the redundancy function. For redundancy, the primary inputs
are each connected to two outputs when they are receiving a signal, but the secondary
inputs become active if the primary inputs do not receive a signal for more than 1 ms
(LOS is asserted for more than 1 ms). SCK = 0 connects input A0 to outputs Y0 and Y1
and input A2 to outputs Y2 and Y3 as the primary connections, with inputs A1 and A3
as the secondary inputs. SCK = 1 reverses the primary/secondary assignments so that
A1 and A3 are primary while A0 and A2 are secondary. Primary/secondary input
assignment changes (by changing the state of the SCK pin) are prevented (locked out)
by internal logic when the change would cause connection to an input that has no
signal.
The following table lists the static mode configuration settings for the VSC7111 device.
Table 2.
Static Mode Mapping
Mode Description
MUXCFG SCK EQMAN
Buffer, non-PCIe, auto EQ
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
Buffer, non-PCIe, manual EQ
Buffer, PCIe, auto EQ
Buffer, PCIe, manual EQ
MUX/fanout, non-PCIe, auto EQ, even inputs primary
MUX/fanout, non-PCIe, manual EQ, even inputs primary
MUX/fanout, non-PCIe, auto EQ, odd inputs primary
MUX/fanout, non-PCIe, manual EQ, odd inputs primary
The EQMAN pin controls the state of the automatic (adaptive) input equalizer.
EQMAN = 0 turns on automatic input equalization, ignoring the manual equalization
control settings. EQMAN = 1 disables automatic equalization and uses the manual
equalization control settings.
Manual input equalization is controlled using the SDA_MOSI, SA2_MISO, and SA3_SSB
pins in the static configuration mode (they are used for serial data addressing in the
programming modes). In conjunction with the low power pin (LOPWR), 16 different
combinations of input equalization are selectable by tying the pins high or low. The
following table shows the static pin settings and equivalent internal register values.
Table 3.
Input EQ Static Mode Settings
ISE1
LOPWR SA3_ SSB SA2_MISO SDA_ MOSI Gain1 Gain2 Short
ISE1
Long
ISE2
Short
ISE2
Long
0
0
0
0
0
0
0
0
0
1
0
0
1
1
0
0
1
0
1
0
11111 11111 00000
11011 11111 00100
10110 11011 01000
10100 10110 01010
10000 10110 01100
00000
00000
00001
00011
00011
00000
00000
00100
01000
01000
00000
00000
00000
00001
00001
Revision 2.0
September 2010
Confidential
Page 13
VITESSE [ VITESSE SEMICONDUCTOR CORPORATION ]
