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238 Software Developer’s Manual
Register Descriptions
SDP6_IODIR
SDP2_IODIR
(82541xx and
82547GI/EI)
10 0b
1
SDP6[2] Pin Directionality. Controls whether software-controllable
pin SDP6[2] is configured as an input or output (0b = input, 1b =
output). Initial value is EEPROM-configurable. This bit is not
affected by software or system reset, only by initial power-on or
direct software writes.
SDP7_IODIR
SDP2_IODIR
(82541xx and
82547GI/EI)
11 0b
1
SDP7[2] Pin Directionality. Controls whether software-controllable
pin SDP7[2] is configured as an input or output (0b = input, 1b =
output). Initial value is EEPROM-configurable. This bit is not
affected by software or system reset, only by initial power-on or
direct software writes.
ASDCHK 12 0b
ASD Check
Initiate an Auto-Speed-Detection (ASD) sequence to sense the
frequency of the PHY receive clock. The results are reflected in
STATUS.ASDV. This bit is self-clearing.
This functionality is provided for diagnostic purposes, regardless of
whether the Auto Speed Detection feature is enabled. This bit is
applicable only for internal PHY mode of operation.
EE_RST 13 0b
EEPROM Reset
When set, initiates a reset-like event to the EEPROM function. This
causes the EEPROM to be read as if a RST# assertion had
occurred. All device functions should be disabled prior to setting
this bit. This bit is self-clearing.
Reserved 14 0b
1
Reserved. Should be set to 0b.
SPD_BYPS 15 0b
Speed Select Bypass
When set to 1b, all speed detection mechanisms are bypassed,
and the Ethernet controller is immediately set to the speed
indicated by CTRL.SPEED. This can be used to override the
hardware clock switching circuitry and give full control to software.
SPD_BYPS differs from the CTRL.FRCSPD function in that
FRCSPD uses the internal clock switching circuitry rather than an
immediate forcing function of the speed settings, as does
SPD_BYPS.
Reserved 16 0b
1
Reserved. Should be set to 0b.
RO-DIS 17 0b
Relaxed Ordering Disabled
When set to 1b, the Ethernet controller does not request any
relaxed ordering transactions in PCI-X mode regardless of the
state of bit 1 in the PCI-X command register. When this bit is clear
and bit 1 of the PCI-X command register is set, the Ethernet
controller requests relaxed ordering transactions.
Note: This is a reserved bit for the 82540EP/EM, 82541xx, and
82547GI/EI. Set to 0b.
Reserved 20:18 0b
Reserved
Should be written with 0b to ensure future compatibility.
Reads as 0b.
Field Bit(s)
Initial
Value
Description