AutoNegotiation
5-9
BMCR (Duplex Status and Speed Status), and BMSR (AutoNegotiation
Complete, Remote Fault, Link).
The
Basic Mode Register (BMCR) Address 0x00
provides control for
enabling, disabling, and restarting the AutoNegotiation process.
The
Basic Mode Status Register (BMSR) Address 0x01
indicates the set
of available abilities for technology types, AutoNegotiation ability, and
Extended Register Capability. These bits are permanently set to indicate
the full functionality of the L80600.
The BMSR also provides status on:
Whether AutoNegotiation is complete (bit 5)
Whether the Link Partner is advertising that a remote fault has
occurred (bit 4)
Whether a valid link has been established (bit 2)
The
AutoNegotiation Advertisement Register (ANAR) Address 0x04
indicates the AutoNegotiation abilities to be advertised by the L80600. All
available abilities are transmitted by default, but any ability can be
suppressed by writing to the ANAR. Updating the ANAR to suppress an
ability is one way for a management agent to change (force) the
technology that is used.
The
AutoNegotiation Link Partner Ability Register (ANLPAR) Address
0x05
is used to receive the base link code word as well as all Next Page
code words during the negotiation.
If Next Page is not being used, the ANLPAR stores the base link code
word (link partner's abilities) and retains this information from the time
the page is received, as indicated by a 1 in bit 1 of the
AutoNegotiate
Expansion Register (ANER) Address 0x06
, through the end of the
negotiation and beyond.
When using the Next Page operation, the L80600 cannot wait for
AutoNegotiation to complete in order to read the ANLPAR, because the
register is used to store both the base and next pages. Software must
be available to perform several functions. The ANER register (register
0x06) must have a page received indication (bit 1). Once the L80600
receives the first page, software must store it in memory if it wants to
keep the information. AutoNegotiation keeps a copy of the base page