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Intel
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82575EB Gigabit Ethernet Controller — Extended Device Control Register - CTRL_EXT
(00018h, R/W)
Intel
®
82575EB Gigabit Ethernet Controller 324632-003
Software Developer’s Manual and EEPROM Guide Revision: 2.1
306 January 2011
14.3.5 Extended Device Control Register - CTRL_EXT
(00018h, R/W)
This register provides extended control of the 82575’s functionality beyond that provided by the Device
Control register (CTRL).
The 82575 allows up to four externally controlled interrupts. All software-definable pins, can be mapped
for use as GPI interrupt bits. These mappings are enabled by the SDPx_GPIEN bits only when these
signals are also configured as inputs via SDPx_IODIR. When configured to function as external interrupt
pins, a GPI interrupt is generated when the corresponding pin is sampled in an active-high state.
The bit mappings are shown in Table 88 for clarity.
Table 88. Bit Mappings
Note:
1. If software uses the EE_RST function and desires to retain current configuration information, the
contents of the control registers should be read and stored by software. Control register values are
changed by a read of the EEPROM which occurs upon assertion of the EE_RST bit.
2. The EEPROM reset function can read configuration information out of the EEPROM which affects the
configuration of PCIe* space BAR settings. The changes to the BARs are not visible unless the
system reboots and the BIOS is allowed to re-map them.
3. The SPD_BYPS bit performs a similar function to the CTRL.FRCSPD bit in that the 82575’s speed
settings are determined by the value software writes to the CRTL.SPEED bits. However, with the
SPD_BYPS bit asserted, the settings in CTRL.SPEED take effect rather than waiting until after the
82575’s clock switching circuitry performs the change.
DONE 1 0b Read Done
Set to 1b when the EEPROM read completes.
Set to 0b when the EEPROM read is in progress.
Writes by software are ignored.
ADDR 15:2 0h Read Address
This field is written by software along with Start Read to indicate the word to read.
DATA (RO) 31:16 X Read Data. Data returned from the EEPROM read.
SDP Pin Used as GPI CTRL_EXT Field Settings
Resulting ICR Bit
(GPI)
Directionality Enable as GPI interrupt
3 SDP3_IODIR SDP3_GPIEN 14
2 SDP2_IODIR SDP2_GPIEN 13
1 SDP1_IODIR SDP1_GPIEN 12
0 SDP0_IODIR SDP0_GPIEN 11