LAN9211 datasheet(58/147 Pages) SMSC

58 / 147 page

High-Performance Small Form Factor Single-Chip Ethernet Controller with HP Auto-MDIX Support

Datasheet

Revision 2.9 (03-01-12)

SMSC LAN9211

DATASHEET

3.12.6.3

TX Example 3

In this example a single, 111-Byte Ethernet packet will be transmitted with a TX checksum. This packet

is divided into four buffers. The four buffers are as follows:

Buffer 0:

4-Byte “Data Start Offset”

4-Byte Checksum Preamble

16-Byte “Buffer End Alignment”

Buffer 1:

7-Byte “Data Start Offset”

79-Bytes of payload data

16-Byte “Buffer End Alignment”

Buffer 2:

0-Byte “Data Start Offset”

15-Bytes of payload data

16-Byte “Buffer End Alignment”

Buffer 3:

10-Byte “Data Start Offset”

17-Bytes of payload data

16-Byte “Buffer End Alignment”

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.

Note: In order to perform a TX checksum calculation on the associated packet, bit 14 (CK) of the TX

Command ‘B’ must be set in conjunction with bit 13 (FS) of TX Command ‘A’ and bit 16

(TXCOE_EN) of the COE_CR register. For more information, refer to Section 3.6.2, "Transmit

Checksum Offload Engine (TXCOE)".

LAN9211 Datasheet(PDF) 58 Page - SMSC Corporation