Datasheet

TSB81BA3E
SLLS783A –MAY 2009–REVISED MAY 2010 www.ti.com
Table 4. Page 0 (Port Status) Register Field Descriptions
FIELD SIZE TYPE DESCRIPTION
TPA line state. This field indicates the instantaneous TPA line state of the selected port, encoded as
follows:
Code Arb Value
11 Z
Astat 2 Rd
01 1
10 0
00 invalid
TPB line state. This field indicates the TPB line state of the selected port. This field has the same
Bstat 2 Rd
encoding as the Astat field.
Child/parent status. A 1 indicates that the selected port is a child port. A 0 indicates that the selected
Ch 1 Rd 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.
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.
Con 1 Rd
NOTE: The Con bit indicates that the port is physically connected to a peer PHY, but this does not
mean that the port is necessarily active. For 1394b-coupled connections, the Con bit is set when a
port detects connection tones from the peer PHY and operating-speed negotiation is completed.
Receive OK. In 1394a-2000 mode this bit indicates the reception of a debounced TPBias signal. In
RxOK 1 Rd Beta mode, this bit indicates the reception of a continuous electrically valid signal.
Note: RxOK is set to false during the time that only connection tones are detected in Beta mode.
Port disabled control. If this bit is 1, then 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
Dis 1 Rd/Wr
affected by bus reset. When this bit is set, the port cannot become active; however, the port still
tones, but does not establish an active connection.
Indicates the maximum speed negotiated between this PHY port and its immediately connected port.
Negotiated_speed 3 Rd The encoding is as for Max_port_speed. It is set during connection when in Beta mode or to a value
established during self-ID when in 1394a-2000 mode.
Port-event-interrupt enable. When this bit is 1, a port event on the selected port sets the
PIE 1 Rd/Wr port-event-interrupt (PEI) bit and notifies the link. This bit is reset to 0 by a hardware reset and is
unaffected by bus reset.
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
Fault 1 Rd/Wr 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 Fault bit to 0. This
bit is reset to 0 by hardware reset and is unaffected by bus reset.
This bit is set to 1 if an error is detected during a standby operation and cleared on exit from the
Standby_fault 1 Rd/Wr standby state. A write of 1 to this bit or receipt of the appropriate remote command packet clears it to
0. When this bit is cleared, standby errors are cleared.
Disable scrambler. If this bit is set to 1, then the data sent during packet transmission is not
Disscrm 1 Rd/Wr
scrambled.
B_Only 1 Rd Beta-mode operation only. For the TSB81BA3E, this bit is set to 0 for all ports.
If this bit is set to 1, the port has detected a dc connection to the peer port by means of a 1394a-style
DC_connected 1 Rd
connect-detect circuit.
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