LAN9221_12 Datasheet, PDF (57/151 Pages) SMSC Corporation – High-Performance 16-bit Non-PCI 10/100 Ethernet Controller with Variable Voltage I/O

High-Performance 16-bit Non-PCI 10/100 Ethernet Controller with Variable Voltage I/O
Datasheet
Figure 3.21, "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 Com m and 'A'
Buffer End Alignment = 1
TXCommand'A'
Data Start Offset = 7
First Segment = 1
TXCommand'B'
Last Segment = 0
Buffer Size = 79
7-Byte Data Start Offset
TX Com m and 'B'
Packet Length = 111
Data Passed to the
TX Data FIFO
TXCommand'A'
TXCommand'B'
79-BytePayload
Pad DWORD 1
10-Byte
EndPadding
31
TX Com m and 'A'
Buffer End Alignment = 1
Data Start Offset = 0
First Segment = 0
Last Segment = 0
Buffer Size = 15
TX Com m and 'B'
Packet Length = 111
0
TXCommand'A'
TXCommand'B'
15-BytePayload
1B
31
0
TX Com m and 'A'
Buffer End Alignment = 1
10-Byte
EnTXdOCoffmsemtPaanddd'iAn'g
Data Start Offset = 10
TXCommand'B'
First Segment = 0
Last Segment = 1
10-Byte
Buffer Size = 17
Data Start Offset
TX Com m and 'B'
Packet Length = 111
17-BytePayloadData
79-BytePayload
TXCommand'A'
15-BytePayload
TXCommand'A'
17-BytePayload
NOTE: Extra bytes
betw een buffers are
not transmitted
5-ByteEndPadding
Figure 3.21 TX Example 1
SMSC LAN9221/LAN9221i
57
DATASHEET
Revision 2.9 (03-01-12)