Altera 40-Gbps Ethernet MAC and PHY MegaCore Function - Manual (Page 54)

bits). In both cases the client interfaces operate at a frequency above 315 MHz in the standard IP core
variations, and at or above the frequency of 190.90 MHz in 24.24 Gbps variations.
The client acts as a source and the TX MAC acts as a sink in the transmit direction.
Figure 3-3: TX Client to MAC Interface with Adapters (Avalon-ST)
The Avalon-ST interface bus width varies with the IP core variation. In the figure, = 4 for the 40GbE
IP core and = 8 for the 100GbE IP core. is log
2
(8*).
l_tx_data[*64-1:0]
l_tx_empty[-1:0]
l_tx_startofpacket
l_tx_endofpacket
l_tx_ready
l_tx_valid
TX MAC
TX Client
Logic
Table 3-2: Signals of the TX Client Interface with Adapters
In the table, = 4 for the 40GbE IP core and = 8 for the 100GbE IP core. is log
2
(8*). All interface
signals are clocked by the
clk_txmac
clock.
Signal Name Direction Description
l_tx_data[*64-1:0] Input TX data. If the preamble pass-through feature is enabled,
data begins with the preamble.
l_tx_empty[-1:0] Input Indicates the number of empty bytes on
l_tx_data
when
l_tx_endofpacket
is asserted.
l_tx_startofpacket Input When asserted, indicates the start of a packet. The packet
starts on the MSB.
l_tx_endofpacket Input When asserted, indicates the end of packet.
UG-01088
2014.12.15
40-100GbE IP Core TX Data Bus with Adapters (Avalon-ST Interface) 3-7
Functional Description Altera Corporation
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