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Ethernet AVB Endpoint User Guide www.xilinx.com 57
UG492 July 23, 2010
Chapter 6
Ethernet AVB Endpoint Transmission
As illustrated in Figure 5-1, data for transmission over an AVB network can be obtained
from three types of sources:
1. AV Tr affic . For transmission from the “Tx AV Traffic I/F” of the core.
2. Precise Timing Protocol (PTP) Packets. Initiated by the software drivers using the
dedicated hardware “Tx PTP Packet Buffer.”
3. Legacy Traffic. For transmission from the “Tx Legacy Traffic I/F” of the core.
Tx Legacy Traffic I/F
The signals forming the Tx Legacy Traffic I/F are defined in Table 5-2. All signals are
synchronous to the Tri-Mode Ethernet MAC transmitter clock, tx_clk, which must
always be qualified by the corresponding clock enable, tx_clk_en (see Table 5-1).
This interface is intentionally identical to the client transmitter interface of the supported
Xilinx Tri-Mode Ethernet MAC core (there is a one-to-one correspondence between signal
names of the block-level wrapper from the Tri-Mode Ethernet MAC example design, after
the legacy_ prefix is removed). This provides backwards compatibility–all existing MAC
client-side designs can connect to the legacy Ethernet port unmodified.