SBPH400-3 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'SBPH400-3' PDF : 43 Pages View PDF
Figure 2.4 PHY configuration packet format
00
root_ID
RT
gap_cnt
0000
0000
logical inverse of first quadlet
SBPH400-3
0000
0000
The fields in the PHY configuration packet are interpreted as shown in Table 2.2.
Table 2.2 PHY configuration packet fields
Field
root_ID
R
T
gap_cnt
Definition
physical ID
set root
set gap count
Gap_Count value
Comment
the physical node identifier of the node to become root on next reset
The Force_Root bit in the SBPH400 is set if R=1 and root_ID = the
node_ID of this node
If T=1, then the value of the gap count register in the SBPH400 is set
to gap_cnt.
new value of Gap Count register
Note that either or both of R and T must be set to 1.
2.7.5 Ping packet
The SBPH400 supports the use of ping timing. The ping packet has the format shown in Figure
2.5:
Figure 2.5 Ping packet format
00
phy_ID
0 0 type (0) 00
0000
0000
logical inverse of first quadlet
0000
0000
When the SBPH400 receives a ping packet from the bus or from the local link addressed to
the node, it responds immediately (without arbitration) with a Self_ID packet to both the bus
and the local link.
2.7.6 Remote Access and Reply
The SBPH supports remote access to its internal registers. On receipt of a remote access
packet addressed to the node (either from the bus or from the local link), the SBPH400 will
immediately respond with the appropriate remote reply packet. The remote access packet and
the reply packet are also forwarded to the local link.
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