XIO3130 Datasheet, PDF (59/139 Pages) Texas Instruments – XIO3130 switch is a PCI Express x1 3-port fanout switch

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XIO3130
SLLS693C – MAY 2007 – REVISED JUNE 2008
4.2.54 Link Status Register
The Link Status register indicates the current state of the PCI Express Link.
PCI register offset:
A2h
Register type:
Read only
Default value:
1X11h
BIT NUMBER
RESET STATE
15 14 13 12 11 10 9
8
7
6
5
4
3
2
1
0
0
0
0
1
0
x
0
0
0
0
0
1
0
0
0
1
BIT
15:13
12
11
10
9:4
3:0
FIELD NAME
RSVD
SCC
LT
UNDEF
NLW
LS
Table 4-30. Bit Descriptions – Link Status Register
ACCESS
r
r
r
r
r
r
DESCRIPTION
Reserved. When read, these bits return zeros.
Slot clock configuration. This bit reflects the reference clock configurations and is read-only 1,
indicating that a 100 MHz common clock reference is used.
Link training in progress. This bit has no function for upstream ports and is read-only zero.
Undefined. The value read from this bit is undefined.
Negotiated link width. This field is read-only 000001b, which indicates that the lane width is x1.
Link speed. This field is read-only 0001b, which indicates that the link speed is 2.5Gb/s.
4.2.55 Serial Bus Data Register
The Serial Bus Data register is used to read and write data on the serial bus interface, e.g., for use with a
serial EEPROM. When writing data to the serial bus, this register must be written before writing to the
Serial Bus Address register to initiate the cycle. When reading data from the serial bus, this register
contains the data read after the REQBUSY (bit 5 Serial Bus Control register) bit is cleared. This register is
reset with PERST.
PCI register offset:
B0h
Register type:
Read/Write
Default value:
00h
BIT NUMBER
RESET STATE
76543210
00000000
4.2.56 Serial Bus Index Register
The value written to the Serial Bus Index register represents the byte address of the byte being read or
written from the serial bus device. The Serial Bus Index register must be written before initiating a serial
bus cycle by writing to the Serial Bus Slave Address register. This register is reset with PERST.
PCI register offset:
B1h
Register type:
Read/Write
Default value:
00h
BIT NUMBER
RESET STATE
76543210
00000000
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XIO3130 Configuration Register Space
59