lan9221 Standard Microsystems Corp., lan9221 Datasheet - Page 61

• Manufacturer Part Number: lan9221
• Description: High-performance 16-bit Non-pci 10/100 Ethernet Controller With Variable Voltage I/o
• Manufacturer: Standard Microsystems Corp.

High-Performance 16-bit Non-PCI 10/100 Ethernet Controller with Variable Voltage I/O
Datasheet
SMSC LAN9221/LAN9221i
TX Checksum Enable = 1
Checksum Preamble
TX Checksum Location = 50
TX Checksum Start Pointer = 14
TX Checksum Enable = 1
TX Checksum Enable = 1
TX Checksum Enable = 1
TX Command 'A'
Buffer End Alignment = 1
Data Start Offset = 4
First Segment = 1
Last Segment = 0
Buffer Size = 4
TX Command 'B'
Packet Length = 115
TX Command 'A'
Buffer End Alignment = 1
Data Start Offset = 7
First Segment = 0
Last Segment = 0
Buffer Size = 79
TX Command 'B'
Packet Length = 115
TX Command 'A'
Buffer End Alignment = 1
Data Start Offset = 0
First Segment = 0
Last Segment = 0
Buffer Size = 15
TX Command 'B'
Packet Length = 115
TX Command 'A'
Buffer End Alignment = 1
Data Start Offset = 10
First Segment = 0
Last Segment = 1
Buffer Size = 17
TX Command 'B'
Packet Length = 115
31
31
31
31
Ethernet Controller
Data Written to the
TX Checksum Preamble
4-Byte Data Start Offset
7-Byte Data Start Offset
17-Byte Payload Data
8-Byte End Padding
5-Byte End Padding
End Offset Padding
TX Command 'A'
TX Command 'B'
TX Command 'A'
TX Command 'B'
TX Command 'A'
TX Command 'B'
TX Command 'A'
TX Command 'B'
Data Start Offset
79-Byte Payload
15-Byte Payload
Pad DWORD 1
End Padding
10-Byte
10-Byte
10-Byte
Figure 3.17 TX Example 3
1B
DATASHEET
0
0
0
0
61
NOTE: When enabled, the TX Checksum
P r e a m b l e i s p r e - p e n d e d t o d a t a t o b e
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.
Data Passed to the
TX Checksum Preamble
TX Data FIFO
TX Command 'A'
TX Command 'B'
TX Command 'A'
TX Command 'A'
TX Command 'A'
79-Byte Payload
15-Byte Payload
17-Byte Payload
NOTE: Extra bytes
between buffers are
not transmitted
Revision 2.6 (12-04-08)