Intel PCI-X Loss of Signal/Link Status Indication, Internal Serdes Mode, Internal PHY Mode

Ethernet Interface

Table 8-9. GMII/MII Mode – Force Link

CTRL.FRCSPD = CTRL.FRCDPLX = CTRL.SLU = 1b

Control Bit	Effect on Control Bits
CTRL.FD	Set by software.
CTRL.SLU	Set by software, and assumed PHY is also forced to assert link.
CTRL.RFCE	Set by software for the desired mode of operation.
CTRL.TFCE	Set by software for the desired mode of operation.
CTRL.SPEED	Set by software.
STATUS.FD	Reflects the value of CTRL.FD.
STATUS.LU	Reflects CTRL.SLU set and internal link status.
STATUS.SPEED	Reflects CTRL.SPEED.

8.6.5Loss of Signal/Link Status Indication

For the 82546GB/EB and 82545GM/EM, the internal LOS signal allows for indication of physical link status to the Ethernet controller’s MAC.

For the 82544GC/EI, the LOS input is provided to allow for indication of physical link status to the Ethernet controller. When the 82544GC/EI is configured in TBI mode, the input is typically connected to the loss-of-signal connection from the optics while in internal PHY mode.

If the LSC (Link Status Change) interrupt is enabled, the hardware posts an interrupt to be serviced by the software driver when the link goes up or down. See Section 3.4.3 for more details.

8.6.5.1Internal Serdes Mode 1

When asserted, LOS indicates there is no activity on the fiber due to either an unplugged cable or a defective optical device. An assertion on LOS implies the link is not available and the hardware is disabled. This is true whether the link is forced by the Set Link Up bit (CTRL.SLU) or if the Ethernet controller is configured to perform Auto-Negotiation. When Auto-Negotiation is enabled, the Ethernet controller is forced to restart Auto-Negotiation but does not complete the negotiation process until the LOS is deasserted.

8.6.5.2Internal PHY Mode

While in internal PHY mode, an internal signal provides status of the physical link as indicated by the PHY. Indication that the link is not up disables MAC operation. Upon determination of a valid link, the assertion of the internal link signal asserts the LSC interrupt (if enabled) to indicate to the software driver to check the link status.

1.TBI mode for the 82544GC/EI.

Software Developer’s Manual 169