EP80579 Datasheet, PDF (1495/1916 Pages) Intel Corporation – Intel® EP80579 Integrated Processor Product Line

Intel^® EP80579 Integrated Processor
37.6.5.3
AIT – Adaptive IFS Throttle Register
Adaptive IFS throttles back-to-back transmissions in the transmit packet buffer and
delays their transfer to the CSMA/CD transmit function. This can be used to delay the
transmission of back-to-back packets on the wire. Normally, this register should be set
to 0. However, if additional delay is desired between back-to-back transmits, then this
register may be set with a value greater than zero.
The Adaptive IFS Throttle timer provides a similar function to the “TIPG – Transmit IPG
Register” on page 1493, however, Adaptive IFS affects only the initial transmission
timing, not re-transmission timing.
Table 37-69. AIT: Adaptive IFS Throttle Register
Description:
View: PCI 1
BAR: CSRBAR
Bus:Device:Function: M:0:0
Offset Start: 0458h
Offset End: 045Bh
View: PCI 2
BAR: CSRBAR
Bus:Device:Function: M:1:0
Offset Start: 0458h
Offset End: 045Bh
View: PCI 3
BAR: CSRBAR
Bus:Device:Function: M:2:0
Offset Start: 0458h
Offset End: 045Bh
Size: 32 bits
Default: 00000000h
GbE0: Aux
Power Well: Gbe1/2:
Core
Bit Range
31 : 16
Bit Acronym
Bit Description
Sticky
Rsvd
Reserved
Adaptive IFS Value
Adaptive IFS throttles back-to-back transmissions in the
transmit packet buffer and delays their transfer to the
CSMA/CD transmit function. Normally, this register should
be set to 0b. However, if additional delay is desired
between back-to-back transmit packets, then this register
can be set with a value greater than zero (0). This feature
can be helpful in high collision half-duplex environments.
Bit Reset
Value
0h
Bit Access
RV
15 : 00
AIFS
In order for AIFS to take effect it should be larger than the
minimum IFS value defined in IEEE 802.3 standard. AIFS
has no effect on transmissions that occur immediately after
receives or transmissions that are not back-to-back. In
addition, it has no effect on re-transmission timing
(retransmission after collisions).
0h
RW
The AIFS value is additive to the TIPG.IPGT value.
This time unit for this value is speed dependent:
1000Mbps is 8ns
100Mbps is 80ns
10 Mbps is 800ns
August 2009
Order Number: 320066-003US
Intel^® EP80579 Integrated Processor Product Line Datasheet
1495