lan9220 Standard Microsystems Corp., lan9220 Datasheet - Page 50

• Manufacturer Part Number: lan9220
• Description: 16-bit Non-pci Small Form Factor 10/100 Ethernet Controller With Variable Voltage I/o & Hp Auto-mdix Support
• Manufacturer: Standard Microsystems Corp.

Revision 2.6 (12-04-08)
3.12.1
TX Buffer Format
TX buffers exist in the host’s memory in a given format. The host writes a TX command word into the
TX data buffer before moving the Ethernet packet data. The TX command A and command B are 32-
bit values that are used by the LAN9220 in the handling and processing of the associated Ethernet
packet data buffer. Buffer alignment, segmentation and other packet processing parameters are
included in the command structure. The following diagram illustrates the buffer format.
Last Buffer in
Figure 3.13 Simplified Host TX Flow Diagram
Packet
16-bit Non-PCI Small Form Factor 10/100 Ethernet Controller with Variable Voltage I/O & HP Auto-MDIX Support
DATASHEET
Command
(optional)
available
Padding
Check
space
Buffer
Write
FIFO
Write
Write
Start
Idle
init
TX
50
TX Status
Available
Not Last Buffer
(optional)
Read TX
Status
SMSC LAN9220
Datasheet