Altera Low Latency 40-Gbps Ethernet MAC and PHY MegaCore Function User Manual
Page 58
For example, the destination MAC address includes the following six octets AC-DE-48-00-00-80. The first
octet transmitted (octet 0 of the MAC address described in the 802.3 standard) is AC and the last octet
transmitted (octet 7 of the MAC address) is 80. The first bit transmitted is the low-order bit of AC, a zero.
The last bit transmitted is the high order bit of 80, a one.
The preceding table and the following figure show that in this example, 0xAC is driven on
DA5
(DA[47:40])
and 0x80 is driven on
DA0
(DA[7:0])
.
Figure 3-9: Octet Transmission on the Avalon-ST Signals Without Preamble Pass-Through
Illustrates how the octets of the client frame are transferred over the TX datapath when preamble pass-
through is turned off.
clk_txmac
l8_tx_data[511:504]
l8_tx_data[503:496]
l8_tx_data[495:488]
l8_tx_data[487:480]
l8_tx_data[479:472]
l8_tx_data[471:464]
l8_tx_data[463:456]
l8_tx_data[455:448]
l8_tx_startofpacket
l8_tx_endofpacket
l8_tx_empty[5:0]
DA5
DA5
DA5
DA4
DA4
DA4
DA3
DA3
DA3
DA2
DA2
DA2
DA1
DA1
DA1
DA0
DA0
DA0
SA5
SA5
SA5
SA4
SA4
SA4
55
50
l8_tx_data[447:440]
l8_tx_data[439:432]
l8_tx_data[431:424]
l8_tx_data[423:416]
l8_tx_data[415:408]
l8_tx_data[407:400]
l8_tx_data[399:392]
l8_tx_data[391:384]
l8_tx_data[7:0]
SA3
D114
D115
D116
D117
D118
D119
D120
D121
D122
D242
D243
D244
D245
D246
D247
D248
D249
D250
D251
D252
D253
D254
D255
SA2
SA1
SA0
TL1
TL0
D0
D1
D49
l8_tx_data[15:8]
D48
l8_tx_data[23:16]
SA3
SA2
SA1
SA0
TL1
TL0
D0
D1
D49
D48
D47
SA3
SA2
SA1
SA0
TL1
TL0
D0
D1
D50
D51
D52
D53
D54
D55
D56
D57
D58
D59
D60
D61
D62
D63
D64
D65
D113
D112
D111
D50
D51
D52
D53
D54
D55
D56
D57
D58
D59
D60
D61
D62
D63
D64
D65
D113
D112
D111
D50
D51
D52
D53
D54
D55
D56
D57
D58
D59
D60
D61
D62
D63
D64
D65
D113
D112
D111
D47
D49
D48
D47
UG-01172
2015.05.04
Order of Transmission
3-13
Functional Description
Altera Corporation