DS33X11+ Maxim Integrated Products, DS33X11+ Datasheet - Page 60

• Manufacturer Part Number: DS33X11+
• Description: IC MAPPING ETHERNET 144CSBGA
• Manufacturer: Maxim Integrated Products

Specifications of DS33X11+

• Applications: Data Transport
• Interface: SPI
• Voltage - Supply: 1.8V, 2.5V, 3.3V
• Package / Case: 144-CSBGA
• Mounting Type: Surface Mount
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

________________________________________________ DS33X162/X161/X82/X81/X42/X41/X11/W41/W11
8.15 Ethernet Interfaces
The Ethernet Interface allows for direct connection to Ethernet PHYs. The interface consists of a dual 10/100Mbps
MII/RMII interface or a single 1000Mbps GMII interface and associated Ethernet MACs. In GMII operation, the
interface contains 23 signals with a reference clock of 125MHz. In dual MII operation, each interface contains of 12
signals and uses a clock reference of 25MHz. In RMII operation, the interface contains 7 signals with a reference
clock of 50MHz. The device can be configured for GMII, MII, or RMII operation with the GL.CR1.P1SPD,
GL.CR1.P2SPD, SU.MACCR.GMIIMIIS bits and the RMII_SEL input pin. In DTE mode of operation, the TX_CLK
and RX_CLK signals are generated by the PHY and are inputs.
The data received from the MII, RMII, or GMII interface(s) is processed by internal IEEE 802.3 compliant Ethernet
MACs. The user can configure a maximum receive frame length beyond which the MAC discards the complete
frame. The maximum frame size can be configured in the SU.MPL register to any value up to 10240 bytes. Sizes
over 2048 bytes are considered “jumbo” frames. For more information on jumbo frame support requirements, see
Table 10-5. The maximum frame length (in bits) is the number specified in SU.MPL multiplied by 8.
The frame length calculation is shown below in Figure 8-8. The frame length includes only destination address,
source address, VLAN tag (2 bytes), type length field, data and CRC32. Note that the calculation used for
maximum frame size results in a different value than the 802.3 Type/Length field shown in the figure.
Figure 8-8. IEEE 802.3 Ethernet Frame
Type /
Preamble
SFD
Destination Adrs
Source Address
Data
CRC32
Length
4
7
1
6
6
2
46-1500
Max Frame Length
The distant end will normally reject the sent frames if jabber timeout, loss of carrier, excessive deferral, late
collisions, excessive collisions, under run, deferred or collision errors occur. Transmission of a frame under any of
these errors will be logged by the MAC management counters. The device provides user the option to not
automatically retransmit the frame if any of the errors have occurred through the MAC’s SU.MACCR.DRTY bit.
Frames received with errors are usually rejected by the device. More information on the Ethernet MAC functions
can be found in Section 8.19.
Rev: 063008
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