LAN9221-ABZJ Standard Microsystems (SMSC), LAN9221-ABZJ Datasheet - Page 53

• Manufacturer Part Number: LAN9221-ABZJ
• Manufacturer: Standard Microsystems (SMSC)

Specifications of LAN9221-ABZJ

• Operating Supply Voltage (typ): 1.8/2.5/3.3V
• Operating Supply Voltage (min): 1.62V
• Operating Supply Voltage (max): 3.6V
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 56
• Lead Free Status / RoHS Status: Compliant

High-Performance 16-bit Non-PCI 10/100 Ethernet Controller with Variable Voltage I/O
Datasheet
SMSC LAN9221/LAN9221i
30:26
25:24
23:21
20:16
15:14
BITS
10:0
31
13
12
11
TX COMMAND ‘A’
Interrupt on Completion. When set, the TXDONE flag will be asserted when the current buffer has
been fully loaded into the TX FIFO. This flag may be optionally mapped to a host interrupt.
Reserved. These bits are reserved. Always write zeros to this field to guarantee future compatibility.
Buffer End Alignment. This field specifies the alignment that must be maintained on the last data
transfer of a buffer. The host will add extra DWORDs of data up to the alignment specified in the
table below. The LAN9221/LAN9221i will remove the extra DWORDs. This mechanism can be used
to maintain cache line alignment on host processors.
Reserved. These bits are reserved. Always write zeros to this field to guarantee future compatibility
Data Start Offset (bytes). This field specifies the offset of the first byte of TX data. The offset value
can be anywhere from 0 bytes to 31 a Byte offset.
Reserved. These bits are reserved. Always write zeros to this field to guarantee future compatibility
First Segment (FS). When set, this bit indicates that the associated buffer is the first segment of the
packet.
Last Segment. When set, this bit indicates that the associated buffer is the last segment of the
packet
Reserved. These bits are reserved. Always write zeros to this field to guarantee future compatibility.
Buffer Size (bytes). This field indicates the number of bytes contained in the buffer following this
command. This value, along with the Buffer End Alignment field, is read and checked by the
LAN9221/LAN9221i and used to determine how many extra DWORD’s were added to the end of the
Buffer. A running count is also maintained in the LAN9221/LAN9221i of the cumulative buffer sizes
for a given packet. This cumulative value is compared against the Packet Length field in the TX
command ‘B’ word and if they do not correlate, the TXE flag is set.
Note:
The buffer size specified does not include the buffer end alignment padding or data start
offset added to a buffer.
[25]
0
0
1
1
Table 3.12 TX Command 'A' Format
[24]
0
1
0
1
DATASHEET
DESCRIPTION
53
16-byte alignment
32-byte alignment
4-byte alignment
End Alignment
Reserved
Revision 2.7 (03-15-10)