Datasheet

16-bit Non-PCI Small Form Factor 10/100 Ethernet Controller with Variable Voltage I/O & HP Auto-MDIX Support
Datasheet
Revision 2.9 (03-01-12) 60 SMSC LAN9220
DATASHEET
Figure 3.23 TX Example 3
031
TX Command 'B'
Pad DWORD 1
7-Byte Data Start Offset
10-Byte
End Padding
Buffer End Alignment = 1
Data Start Offset = 7
First Segment = 0
Last Segment = 0
Buffer Size = 79
031
TX Command 'B'
10-Byte
End Offset Padding
Buffer End Alignment = 1
Data Start Offset = 0
First Segment = 0
Last Segment = 0
Buffer Size = 15
031
TX Command 'B'
Buffer End Alignment = 1
Data Start Offset = 10
First Segment = 0
Last Segment = 1
Buffer Size = 17
10-Byte
Data Start Offset
TX Command 'A'
TX Command 'B'
TX Command 'A'
TX Command 'B'
TX Command 'A'
TX Command 'B'
NOTE: Extra bytes
between buffers are
not transmitted
Data Written to the
Ethernet Controller
Data Passed to the
TX Data FIFO
5-Byte End Padding
TX Command 'A'
TX Command 'B'
TX Command 'A'
TX Command 'A'
79-Byte Payload
15-Byte Payload
17-Byte Payload
NOTE: When enabled, the TX Checksum
Preamble is pre-pended to data to be
transmitted. The FS bit in TX Command 'A', the
CK bit in TX Command 'B' and the TXCOE_EN
bit in the COE_CR register must all be set for
the TX checksum to be generated. FS must
not be set for subsequent fragments of the
same packet.
TX Command 'A'
031
TX Command 'B'
4-Byte Data Start Offset
8-Byte End Padding
Buffer End Alignment = 1
Data Start Offset = 4
First Segment = 1
Last Segment = 0
Buffer Size = 4
Packet Length = 115
TX Command 'A'
TX Command 'B'
TX Checksum Location = 50
Checksum Preamble
TX Checksum Start Pointer = 14
TX Command 'A'
TX Checksum Preamble
TX Checksum Preamble
TX Command 'A'
79-Byte Payload
TX Command 'A'
15-Byte Payload
1B
TX Command 'A'
17-Byte Payload Data
TX Checksum Enable = 1
Packet Length = 115
TX Checksum Enable = 1
Packet Length = 115
TX Checksum Enable = 1
Packet Length = 115
TX Checksum Enable = 1