SBPH400-3
Table 2.16 SBPH400 register fields (continued)
Field
Page_select
Port_select
rsv
Size
3
4
Type Description
R/W Select extended register page for a subsequent PHY register read or
write operation.
0 = Port Status Page
1 = Product Identification Page
Initialized to 0 on power reset.
R/W Identify the port for the selected register page for a subsequent PHY
register read or write operation. For values 0, 1 and 2, the page is as
defined in Table 2.17. For all other values, a subsequent write to any
register in the page has no effect, and a subsequent read from any
register in the page returns zero. Initialized to 0 on power reset.
R/W Field reserved in P1394a for future use. No effect on write, always
reads as zero.
Table 2.17 Port status page
Address
1000
1001
1010-1111
0
1
2
3
4
5
6
7
AStat
BStat
Child Con
Bias
Dis
Negotiated_speed
Int_
Fault
rsv
enable
rsv
Table 2.18 Port status register fields
Field
AStat
BStat
Child
Con
Bias
Dis
Negotiated_speed
Size
2
2
1
1
1
1
3
Type
R
R
R
R
R
R/W
R
Description
TPA line state on the selected port
(112 = Z, 012 = 1,102 = 0, 002 = invalid).
TPB line state on the selected port
(112 = Z, 012 = 1,102 = 0, 002 = invalid).
If 1 the corresponding port is a child, else parent (only
valid after Self_ID)
If 1 the corresponding port is connected, 0 if the port is
disconnected.
Reflects the Bias detected status on the port (1 = Bias
detected) after filtering
The port is disabled when this bit is set to 1, and
enabled when this bit is set to 0. Initialized to the value
of the PDISABLE pin on power reset.
The negotiated speed for this port (only valid after
Self_ID). Possible values are 000b (S100), 001b
(S200), 010b (S400)
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