TXC-06880BIOG Transwitch Corporation, TXC-06880BIOG Datasheet - Page 67

• Manufacturer Part Number: TXC-06880BIOG
• Manufacturer: Transwitch Corporation

Specifications of TXC-06880BIOG

• Operating Supply Voltage (typ): 1.8/3.3V
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Lead Free Status / RoHS Status: Not Compliant

PRELIMINARY TXC-06880-MB, Ed. 4
February 2005
6.2.4 Transmit MAC Configurable Options and Checks
6.2.4.1 Frame Check Sequence (FCS) Generation Option:
6.2.4.2 Pad Short Ethernet Frames Option:
6.2.4.3 Frame Length Check:
6.2.4.4 Maximum Frame Size Check:
6.2.4.5 Back to Back Interframe Gap Option:
6.2.4.6 Source Address Replace Option:
6.2.4.7 PAUSE Frame Filter Option:
6.2.4.8 Preamble Length Option:
Following are the configurable options and checks for the MAC for the outgoing Ethernet
frame.
The MAC provides the option to append the correct FCS when Ethernet frames presented to
the Envoy-CE2 at the SPI-3 Input interface, do not contain a valid FCS. Please note that this
option also works in conjunction with the pad option.
The MAC can be configured to pad short frames to 64 bytes and append the correct FCS. If
this option is set, the FCS generation option is ignored. The pad option is for Ethernet frames
presented at the SPI-3 Input interface with lengths less than 64 bytes.
The length field of the received Ethernet frame is checked against the actual data length for
correctness. The Frame length check enable bit is programmable (Register 0x4004 Bit 4).
The maximum size of the accepted Ethernet frame is programmable. The default value is
1536 (decimal) bytes. Frames exceeding the programmed maximum frame size are
truncated. Truncated frames are tagged with RX_ER. The maximum frame size check is
disabled by setting the Huge Frame Enable configuration bit (Register 0x4004 Bit 5).
The Interframe Gap (IFG) between two back to back transmitted Ethernet frames is
programmable. The default value of the Minimum IFG is 96 bits (decimal).
The MAC provides the option to replace the source address (SA field) of the Ethernet frame
received at the SPI-3 Input interface with the programmed source address (Register 0x4084
Bit 21). The Envoy-CE2 has programmable per port source address registers.
The MAC provides the option to filter PAUSE frames received at the SPI-3 Input Interface.
The option is provided to filter PAUSE frames with the specified Multicast address (01-80-C2-
00-00-01) or to filter all PAUSE frames from the SPI-3 interface destined for the Ethernet
Transmit interface (Register 0x4084 Bit 28). These frames will be errored by forcing the MAC
to append an incorrect CRC.
The Preamble length of the transmitted Ethernet frame is programmable by the MAC. The
default value is 7 bytes (Register 0x4004 Bits 12-15).
- Operation -
Envoy-CE2 Device
DATA SHEET
TXC-06880
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