
PHY Register Configuration
201
September 2005
SCPS110
10.4 Vendor-Dependent Register
The vendor-dependent page provides access to the special control features of the controller, as well as to
configuration and status information used in manufacturing test and debug. This page is selected by writing
7 to the Page_Select field in base register 7. Table 107 shows the configuration of the vendor-dependent
page, and Table 108 shows the corresponding field descriptions.
Table 107. Page 7 (Vendor-Dependent) Register Configuration
BIT POSITION
ADDRESS
0
1
2
3
4
5
6
7
1000
NPA
Reserved
Link_Speed
1001
Reserved for test
1010
Reserved for test
1011
Reserved for test
1100
Reserved for test
1101
Reserved for test
1110
Reserved for test
1111
Reserved for test
Table 108. Page 7 (Vendor-Dependent) Register Field Descriptions
FIELD
SIZE
TYPE
DESCRIPTION
NPA
1
RW
Null-packet actions flag. This bit instructs the PHY layer to not clear fair and priority requests when a null
packet is received with arbitration acceleration enabled. If this bit is set to 1b, fair and priority requests are
cleared only when a packet of more than 8 bits is received; ACK packets (exactly 8 data bits), null packets (no
data bits), and malformed packets (less than 8 data bits) do not clear fair and priority requests. If this bit is
cleared to 0b, fair and priority requests are cleared when any non-ACK packet is received, including null
packets or malformed packets of less than 8 bits. This bit is cleared to 0b by system (hardware) reset and is
unaffected by bus reset.
Link_Speed
2
RW
Link speed. This field indicates the top speed capability of the attached LLC. Encoding is as follows:
Code
Speed
00
S100
01
S200
10
S400
11
illegal
This field is replicated in the sp field of the self-ID packet to indicate the speed capability of the node (PHY and
LLC in combination). However, this field does not affect the PHY speed capability indicated to peer PHYs
during self-ID; the PCIxx12 PHY layer identifies itself as S400 capable to its peers regardless of the value in
this field. This field is set to 10b (S400) by system (hardware) reset and is unaffected by bus reset.