Datasheet

High Performance Single-Chip 10/100 Non-PCI Ethernet Controller
Datasheet
SMSC LAN9118 51 Revision 1.5 (07-11-08)
DATASHEET
3.12.6.2 TX Example 2
In this example, a single 183-Byte Ethernet packet will be transmitted. This packet is in a single buffer
as follows:
 2-Byte “Data Start Offset”
 183-Bytes of payload data
 4-Byte “Buffer End Alignment”
Figure 3.15, "TX Example 2" illustrates the TX command structure for this example, and also shows
how data is passed to the TX data FIFO. Note that the packet resides in a single TX Buffer, therefore
both the FS and LS bits are set in TX command ‘A’.
Figure 3.15 TX Example 2
TX Command 'A'
031
TX Command 'B'
Data Written to the
Ethernet Controller
TX Command 'B'
183-Byte Payload Data
Data Start Offset = 6
First Segment = 1
Last Segment = 1
Buffer Size =183
Packet Length = 183
TX Command 'A'
TX Command 'B'
Data Passed to the
TX Data FIFO
Buffer End Alignment = 0
3B End Padding
TX Command 'A'
6-Byte Data Start Offset
183-Byte Payload Data
NOTE: Extra bytes between buffers
are not transmitted