High-Performance Single-Chip 10/100 Ethernet Controller with HP Auto-MDIX
Datasheet
Figure 3.13, "TX Example 1" illustrates the TX command structure for this example, and also shows
how data is passed to the TX data FIFO.
Data Written to the
Ethernet Controller
31
0
TX Command 'A'
Buffer End Alignment = 1
Data Start Offset = 7
TXCommand'A'
TXCommand'B'
Data Passed to the
TX Data FIFO
First Segment = 1
Last Segment = 0
Buffer Size = 79
7-Byte Data StartOffset
TXCommand'A'
TXCommand'B'
TX Command 'B'
Packet Length = 111
79-BytePayload
Pad DWORD 1
79-BytePayload
10-Byte
EndPadding
TXCommand'A'
15-BytePayload
31
0
TX Command 'A'
Buffer End Alignment = 1
Data Start Offset = 0
First Segment = 0
Last Segment = 0
Buffer Size = 15
TXCommand'A'
TXCommand'B'
TXCommand'A'
17-BytePayload
15-BytePayload
1B
TX Command 'B'
Packet Length = 111
31
0
10-Byte
EndOffsetPadding
TX Command 'A'
TXCommand'A'
Buffer End Alignment = 1
Data Start Offset = 10
TXCommand'B'
First Segment = 0
Last Segment = 1
Buffer Size = 17
10-Byte
Data StartOffset
NOTE: Extra bytes
betw een buffers are
not transmitted
TX Command 'B'
Packet Length = 111
17-BytePayloadData
5-ByteEndPadding
Figure 3.13 TX Example 1
Revision 1.5 (07-18-06)
SMSC LAN9218
DATA4S8HEET
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