TNETE2008

OctalPHY

EIGHT 10BASE-T PHYSICAL-LAYER INTERFACES

SPWS042B – DECEMBER 1997 – REVISED JUNE 1998

19

POST OFFICE BOX 655303

non-data MAC-to-PHY and PHY-to-MAC control exchanges

Figure 9 shows the control information exchange for the case where the MAC is forcing the configuration of the

link. In this case the link is established by link pulse detection and is configured as specified by the MAC. The

TNETE2008 latches the final values just before IFLINK asserts. The force configuration mode should be used

only when the abilities of the link partner are known or set to be the same as those forced. Failure to do this could

result in an incompatibly configured link, e.g., TNETE2008 full duplex and link partner half duplex.

IFLINK going low or any transition on IFFORCEHD can trigger renegotiation. If a new trigger occurs before a

negotiation completes, the process starts over at the beginning of an enforced 1.2-s wait. At the end of an

undisturbed 1.2-s wait, the state of IFFORCEHD and IFTXD3–IFTXD0 determines the modes advertised to the

link partner. IFFORCEHD low commands half duplex; only IFFORCEHD high allows the value clocked from

IFTXD0 to determine duplex mode. In the force configuration mode, IFTXD0 alone determines the duplex mode

for the next time link is established.