HFIXF1110CC.B3-998844 Cortina Systems Inc, HFIXF1110CC.B3-998844 Datasheet - Page 44

• Manufacturer Part Number: HFIXF1110CC.B3-998844
• Description: IC ETHERNET MAC 10PORT 552-CBGA
• Manufacturer: Cortina Systems Inc

Specifications of HFIXF1110CC.B3-998844

• Controller Type: Ethernet Controller, MAC
• Interface: SPI-4.2
• Voltage - Supply: 1.8 V, 2.5 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 575-BCBGA Exposed Pad (552 Bumps)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Supply: -
• Other names: 1008-1010

IXF1110 MAC
Datasheet
250210, Revision 11.0
13 April 2009
5.1.3
5.1.3.1
Cortina Systems
Flow Control
Flow Control is an IEEE 802.3x-defined mechanism for one network node to request that its
link partner take a temporary “Pause” in packet transmission. This allows the requesting
network node to prevent FIFO overruns and dropped packets, by managing incoming traffic
to fit its available memory. The temporary pause allows the device to process packets
already received or in transit, thus freeing up the FIFO space allocated to those packets.
The IXF1110 MAC implements the IEEE 802.3x standard RX FIFO threshold-based Flow
Control. When appropriately programmed, the MAC can both generate and respond to
IEEE standard pause frames. The IXF1110 MAC also supports externally triggered flow
control through the Transmit Pause Control interface.
802.3x Flow Control (Full-Duplex Operation)
The IEEE 802.3x standard identifies four options related to system flow control:
The IXF1110 MAC supports all four options on a per-port basis. Bits 1:0 of the
($ Port_Index + 0x12), on page 127
flow control in each direction independently.
The IEEE 802.3x flow control mechanism is accomplished within the MAC sublayer, and is
based on RX FIFO thresholds called watermarks. The RX FIFO level rises and falls as
packets are received and processed. When the RX FIFO reaches a watermark (either
exceeding a High or dropping below a Low after exceeding a High), the IXF1110 MAC
control sublayer signals an internal state machine to transmit a PAUSE frame. The FIFOs
automatically generate PAUSE frames (also called control frames) to initiate the following:
Figure 5
®
• No Pause
• Symmetric Pause (both directions)
• Asymmetric Pause (Receive direction only)
• Asymmetric Pause (Transmit direction only)
• Halt the link partner when the High watermark is reached.
• Restart the link partner when the data stored in the FIFO falls below the Low watermark.
IXF1110 10-Port 1000 Mbps Ethernet Media Access Controller
illustrates the IEEE 802.3 FIFO flow control functions.
provide programmable control for enabling or disabling
5.1 Media Access Controller
FC Enable
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