Datasheet
SLLS424G − JUNE 2000 − REVISED DECEMBER 2004
25
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APPLICATION INFORMATION
Table 4. Page 0 (Port Status) Register Field Descriptions
FIELD SIZE TYPE DESCRIPTION
Astat 2 Rd TPA line state. This field indicates the TPA line state of the selected port, encoded as follows:
Code Line State
11 Z
01 1
10 0
00 invalid
Bstat 2 Rd TPB line state. This field indicates the TPB line state of the selected port. This field has the same
encoding as the Astat field.
Ch 1 Rd Child/parent status. A 1 indicates that the selected port is a child port. A 0 indicates that the selected port
is the parent port. A disconnected, disabled, or suspended port is reported as a child port. The Ch bit
is invalid after a bus reset until tree-ID has completed.
Con 1 Rd Debounced port connection status. This bit indicates that the selected port is connected. The connection
must be stable for the debounce time of approximately 341 ms for the con bit to be set to 1. The con bit
is reset to 0 by hardware reset and is unaffected by bus reset.
NOTE: The con bit indicates that the port is physically connected to a peer PHY, but the port is not
necessarily active.
Bias 1 Rd Debounced incoming cable bias status. A 1 indicates that the selected port is detecting incoming cable
bias. The incoming cable bias must be stable for the debounce time of 52 µs for the bias bit to be set
to 1.
Dis 1 Rd/Wr Port disabled control. If 1, the selected port is disabled. The dis bit is reset to 0 by hardware reset (all
ports are enabled for normal operation following hardware reset). The dis bit is not affected by bus reset.
Peer_Speed 3 Rd Port peer speed. This field indicates the highest speed capability of the peer PHY connected to the
selected port, encoded as follows:
Code Peer Speed
000 S100
001 S200
010 S400
011–111 invalid
The Peer_Speed field is invalid after a bus-reset until self-ID has completed.
NOTE: Peer speed codes higher than 010b (S400) are defined in IEEE 1394a-2000. However, the
TSB41AB2 is only capable of detecting peer speeds up to S400.
PIE 1 Rd/Wr Port event interrupt enable. When set to 1, a port event on the selected port sets the port event interrupt
(PEI) bit and notify the link. This bit is reset to 0 by hardware reset and is unaffected by bus reset.
Fault 1 Rd/Wr Fault. This bit indicates that a resume-fault or suspend-fault has occurred on the selected port and that
the port is in the suspended state. A resume-fault occurs when a resuming port fails to detect incoming
cable bias from its attached peer. A suspend-fault occurs when a suspending port continues to detect
incoming cable bias from its attached peer. Writing 1 to this bit clears the bit to 0. This bit is reset to 0
by hardware reset and is unaffected by bus reset.