TNETX15AE Datasheet, PDF (22/78 Pages) Texas Instruments – ADDRESS-LOOKUP DEVICE

TNETX15AE
ADDRESS-LOOKUP DEVICE
SPWS041A – AUGUST 1997 – REVISED OCTOBER 1997
management-table lookup interface at 0x0B–0x16 (DIO)
BYTE 3
BYTE 2
Findnode23–Findnode16 Findnode31–Findnode24
Findport
Findcontrol
BYTE 1
BYTE 0
Findnode39–Findnode32 Findnode47–Findnode40
Findnode7–Findnode0 Findnode15–Findnode8
Findnodeage
DIO ADDRESS
0x0C
0x10
0x14
The management-table lookup registers allow the management entity to find information about the node
addresses contained in the table.
These registers are part of the address lookup/inspection mechanism supported through the DIO (host)
interface. An address is fully described by the six bytes of findnode (0xC to 0x11). Data about an address is
returned in findport (0x12). FIND commands are issued through the findcontrol (0x16) register. They are
discussed later in more detail in numerical order.
To cause a FIND operation to execute, the host writes to the findcontrol register (0x16). To find the first address
in the table, execute a FIRST command. The target MAC address is returned in six bytes of findnode registers.
If a successive FIND command is executed (findnext), the starting point to continue the search is the six bytes
of findnode. The results are returned in the same registers, overwriting the original values. These registers can
be read/write between FINDS; a find next picks up with the current values of findnode. If a lookup on an address
to check parameters is executed, the data returned corresponds to the value in the six bytes of findnode when
the lookup command was given; the address parameters are posted in the findport register (0x12, 0x13). The
FIND operation completion is detected when the command bit is written back to 0 (poll). The find register block
is discussed later in further detail in numerical order.
lookup-node address register, findnode at 0x0C–0x11 (DIO)
The findnode registers are used to exchange addresses between the TNETX15AE and the management CPU.
The node address in findnode is kept in Ethernet native data format; bit 40 is the group/specific bit. The function
of findnode depends on the bits set in findcontrol:
D On FIRST operations, this register shows the first address in the lookup table. The data in findnode is valid
only when the FOUND bit in findcontrol is a 1.
D On NEXT operations, this register shows the next address in the lookup table. The data in findnode is valid
only when the FOUND bit in findcontrol is a 1.
D On LKUP operations, the lookup logic operation looks up the address stored in this register. If found, the
FOUND bit in findcontrol is set to a 1.
This register is readable/writeable. While any of the FIND command bits are set, writes to these addresses
are ignored.
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