TSB41BA3B_16 Datasheet, PDF (21/68 Pages) Texas Instruments – IEEE 1394b THREE-PORT CABLE TRANSCEIVER/ARBITER

TSB41BA3B
IEEE 1394b THREE-PORT CABLE TRANSCEIVER/ARBITER
SLLS678 − SEPTEMBER 2005
APPLICATION INFORMATION
Address
0000
0001
0010
0011
0100
0101
0110
0111
Table 2. Base Register Configuration
BIT POSITION
0
1
2
3
4
5
6
7
Physical ID
R
CPS
RHB
IBR
Gap_Count
Extended (111b)
Num_Ports (0011b)
PHY_Speed (111b)
SREN
Delay (1111b)
LCtrl
C
Jitter (000b)
Pwr_Class
WDIE
ISBR
CTOI
CPSI
STOI
PEI
EAA
EMC
Max Legacy SPD
BLINK
Bridge
Rsvd
Page_Select
Rsvd
Port_Select
Table 3. Base Register Field Descriptions
FIELD
Physical ID
R
CPS
RHB
IBR
Gap_Count
Extended
Num_Ports
PHY_Speed
SREN
Delay
SIZE TYPE
DESCRIPTION
6 Rd
This field contains the physical address ID of this node determined during self-ID. The physical-ID is invalid after
a bus reset until the self-ID has completed as indicated by an unsolicited register 0 status transfer from the PHY
to the LLC.
1 Rd
Root. This bit indicates that this node is the root node. The R bit is reset to 0 by bus reset, and is set to 1 during
tree-ID if this node becomes root.
1 Rd
Cable-power status. This bit indicates the state of the CPS input terminal. The CPS terminal is normally tied to
serial bus cable power through a 400-kΩ resistor. A 0 in this bit indicates that the cable-power voltage has
dropped below its threshold for ensured reliable operation.
1 Rd/Wr Root-holdoff bit. This bit instructs the PHY to attempt to become root after the next bus reset. The RHB bit is reset
to 0 by a hardware reset and is unaffected by a bus reset. If two nodes on a single bus have their root holdoff bit
set, then the result is not defined. To prevent two nodes from having their root-holdoff bit set, this bit must only be
written using a PHY configuration packet.
1 Rd/Wr Initiate bus reset. This bit instructs the PHY to initiate a long (166-μs) bus reset at the next opportunity. Any
receive or transmit operation in progress when this bit is set completes before the bus reset is initiated. The IBR
bit is reset to 0 after a hardware reset or a bus reset. Care must be exercised when writing to this bit to not change
the other bits in this register. It is recommended that whenever possible a bus reset be initiated using the ISBR bit
and not the IBR bit.
6 Rd/Wr Arbitration gap count. This value sets the subaction (fair) gap, arb-reset gap, and arb-delay times. The gap count
can be set either by a write to the register, or by reception or transmission of a PHY_CONFIG packet. The gap
count is reset to 3Fh by hardware reset or after two consecutive bus resets without an intervening write to the gap
count register (either by a write to the PHY register or by a PHY_CONFIG packet). It is strongly recommended
that this field only be changed using PHY configuration packets.
3 Rd
Extended register definition. For the TSB41BA3B, this field is 111b, indicating that the extended register set is
implemented.
4 Rd
Number of ports. This field indicates the number of ports implemented in the PHY. For the TSB41BA3B, this field
is 3.
3 Rd
PHY speed capability. This field is no longer used. For the TSB41BA3B PHY, this field is 111b. Speeds for 1394b
PHYs must be checked on a port-by-port basis.
1 Rd/Wr Standby/restore enable. This bit when set to 1 enables the port to go into the standby reduced power state when
commanded by a Standby PHY command packet. This enable works for all ports of the local device. Note the
1394b standard only allows leaf (one port connected) nodes to be placed into standby mode.
4 Rd
PHY repeater data delay. This field indicates the worst-case repeater data delay of the PHY, expressed as
144+(delay × 20) ns. For the TSB41BA3B, this field is Fh. The worst-case repeater delay for S100B is 538 ns.
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