Datasheet
TSB41BA3D
www.ti.com
............................................................................................................................................... SLLS959A – DECEMBER 2008 – REVISED MARCH 2009
Table 7. Page 0 (Port Status) Register Field Descriptions (continued)
FIELD SIZE TYPE DESCRIPTION
Max_port_speed 3 Rd/Wr
Max_port_speed
The maximum speed at which a port is allowed to operate in Beta mode. The encoding is:
000 = S100
001 = S200
010 = S400
011 = S800
100 = S1600
101 = S3200
110 = reserved
111 = reserved
An attempt to write to the register with a value greater than the hardware capability of the port
results in the maximum value that the port is capable of being stored in the register. The port
uses this register only when a new connection is established in the Beta mode or when a port
is programmed as a Beta-only port. When a port is programmed as a bilingual port, it is fixed
at S400 for the Beta speed and is not updated by a write to this register. The power reset
value is the maximum speed capable of the port. Software can modify this value to force a
port to train at a lower-than-maximum speed (when in a Beta-only mode), but no lower than
the minimum speed.
LPP 1 Rd This flag is set permanently to 1.
(Local_plug_present)
Cable_speed 3 Rd This variable is set to the maximum speed that the port is capable of in Beta mode. The
encoding is the same as for Max_port_speed.
Connection_unreliable 1 Rd/Wr If this bit is set to 1, then a Beta-mode speed negotiation has failed or synchronization has
failed. A write of 1 to this field resets the value to 0.
Beta_mode 1 Rd Operating in Beta mode. If this bit is 1, the port is operating in Beta mode; it is equal to 0
otherwise (that is, when operating in 1394a-2000 mode, or when disconnected). If Con is 1,
RxOK is 1, and Beta_mode is 0, then the port is active and operating in the 1394a-2000
mode.
Port_error 8 Rd/Wr Incremented whenever the port receives an invalid codeword, unless the value is already 255.
Cleared when read (including being read by means of a remote access packet). Intended for
use by a single bus-wide diagnostic program.
Sleep_Flag 1 Rd This bit is set to 1 if the port is in the sleep state. The transition to the sleep state occurs only
if the port has been enabled for the sleep mode.
Sleep_enable 1 Rd/Wr This bit is set to 1 if the port has been enabled for sleep mode. If the SLPEN terminal is
sampled high during reset, then this bit is set high for all ports. If sampled low, then it is 0.
Software can individually enable or disasble sleep mode for a port by writing to this bit. Sleep
mode operation is described in the IDB-1394 specification. In PMC mode when no link is
present, the sleep state of each port can be monitored on the data lines as described in the
Terminal Functions table entry for LCLK_PMC.
Loop_disable 1 Rd This bit is set to 1 if the port has been placed in the loop-disable state as part of the loop-free
build process (the PHYs at either end of the connection are active, but if the connection itself
were activated, then a loop would exist). Cleared on bus reset and on disconnection.
In_standby 1 Rd This bit is set to 1 if the port is in standby power-management state.
Hard_disable 1 Rd/Wr No effect unless the port is disabled. If this bit is set to 1, the port does not maintain
connectivity status on an ac connection when disabled. The values of the Con and RxOK bits
are forced to 0. This flag can be used to force renegotiation of the speed of a connection. It
can also be used to place the device into a lower-power state because when hard-disabled, a
port no longer tones to maintain 1394b ac-connectivity status.
The vendor identification page identifies the vendor/manufacturer and compliance level. The page is selected by
writing 1 to the Page_Select fieldin base register 7. Table 8 shows the configuration of the vendor identification
page, and Table 9 shows the corresponding field descriptions.
Copyright © 2008 – 2009, Texas Instruments Incorporated Submit Documentation Feedback 23
Product Folder Link(s): TSB41BA3D