8101 Datasheet, PDF (23/172 Pages) LSI Computer Systems – Gigabit Ethernet Controller

Figure 2.3 Frame Formats and Bit Ordering
System Interface
MAC
10-Bit PHY
Interface
[5] PRE
SFD
[3]
TXD[0]
RXD[0]
DA
TXD[31]
RXD[31]
SOF ^DA[0:7]
DA[8:15] DA[16:23] DA[24:31]
DA[32:39] DA[40:47] SA[0:7] SA[8:15]
SA
SA[16:23] SA[24:31] SA[32:39] SA[40:47]
LT[0:7]
LT[8:16] DATA[0:7] DATA[7:15]
DATA[16:23] DATA[24:31]
L/T
EOF FCS[15:8]
[2]
LSB
FCS[31:24] FCS[23:16]
FCS[7:0]
INVALID
STATUS WORD [1]
MSB
DATA
10101010
10101010
10101010
10101010
10101010
10101010
10101010
10101011
DA [0:7]
DA [8:15]
DA [16:23]
DA [24:31]
DA [32:39]
DA [40:47]
SA [0:7]
SA [8:15]
SA [16:23]
SA [24:31]
SA [32:39]
SA [40:47]
LT [0:7]
LT [8:15]
DATA[0:7]
DATA[8:15]
DATA[16:23]
DATA[24:31]
/I2/
/I2/
/S/
D21.2
D21.2
D21.2
D21.2
D21.2
D21.2
D21.6
<DA [0:7]> ^[7]
<DA [8:15]>
<DA [16:23]>
<DA [24:31]>
<DA [32:39]>
<DA [40:47]>
<SA [0:7]>
<SA [8:15]>
<SA [16:23]>
<SA [24:31]>
<SA [32:39]>
<SA [40:47]>
<LT [0:7]>
<LT [8:15]>
<DATA[0:7]>
<DATA[8:15]>
<DATA[16:23]>
<DATA[24:31]>
Notes:
[1] Status word on receive only is
programmable
[2] EOF position is programmable
[3] Little endian format (default)
[4] Second /R/ added only if transmit packet
ends on odd number of bytes
[5] XMT preamble appended
Receive preamble stripped
[6] XMT CRC not appended
Receive CRC not stripped
[7] < > Means 10B encoded
[8] /I1/ or /I2/, depends on running disparity
[6] FCS
FCS[31:24]
FCS[23:16]
FCS[15:8]
FCS[7:0]
<FCS[31:24]>
<FCS[23:16]>
<FCS[15:8]>
<FCS[7:0]>
/T/
/R/
/R/
[4]
/I1/ or /I2/ [8]
/I2/
/I2/
PCS 8B
ABCDEFGH
abcdefghij
LSB
MSB TX[0]
Bytes
RX[0]
Transmitted _Bits
Transmitted
TX[9]
RX[9]
PCS 10B
10-Bit
PHY
Interface
Transmit Data Path
2-5
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