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LAN9215I-MT 参数 Datasheet PDF下载

LAN9215I-MT图片预览
型号: LAN9215I-MT
PDF下载: 下载PDF文件 查看货源
内容描述: 高效的单芯片10/100以太网控制器与HP Auto-MDIX的和工业温度支持 [Highly Efficient Single-Chip 10/100 Ethernet Controller with HP Auto-MDIX and Industrial Temperature Support]
分类和应用: 外围集成电路数据传输控制器局域网以太网局域网(LAN)标准时钟
文件页数/大小: 134 页 / 1602 K
品牌: SMSC [ SMSC CORPORATION ]
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Highly Efficient Single-Chip 10/100 Ethernet Controller with HP Auto-MDIX and Industrial Temperature Support  
Datasheet  
TX COMMAND ‘B’  
Table 3.12 TX Command 'B' Format  
DESCRIPTION  
BITS  
31:16  
Packet Tag. The host should write a unique packet identifier to this field. This identifier is added to  
the corresponding TX status word and can be used by the host to correlate TX status words with  
their corresponding packets.  
Note:  
The use of packet tags is not required by the hardware. This field can be used by the LAN  
software driver for any application. Packet Tags is one application example.  
15:14  
13  
Reserved. These bits are reserved. Always write zeros to this field to guarantee future compatibility.  
Add CRC Disable. When set, the automatic addition of the CRC is disabled.  
12  
Disable Ethernet Frame Padding. When set, this bit prevents the automatic addition of padding to  
an Ethernet frame of less than 64 bytes. The CRC field is also added despite the state of the Add  
CRC Disable field.  
11  
Reserved. These bits are reserved. Always write zeros to this field to guarantee future compatibility.  
10:0  
Packet Length (bytes). This field indicates the total number of bytes in the current packet. This  
length does not include the offset or padding. If the Packet Length field does not match the actual  
number of bytes in the packet the Transmitter Error (TXE) flag will be set.  
3.14.3  
TX Data Format  
The TX data section begins at the third DWORD in the TX buffer (after TX command ‘A’ and TX  
command ‘B’). The location of the first byte of valid buffer data to be transmitted is specified in the  
“Data Start Offset” field of the TX command ‘A’ word. Table 3.13, "TX DATA Start Offset", shows the  
correlation between the setting of the LSB’s in the “Data Start Offset” field and the byte location of the  
first valid data byte. Additionally, transmit buffer data can be offset by up to 7 additional DWORDS as  
indicated by the upper three MSB’s (5:2) in the “Data Start Offset” field.  
Table 3.13 TX DATA Start Offset  
Data Start Offset [1:0]:  
First TX Data Byte:  
11  
10  
01  
00  
D[31:24]  
D[23:16]  
D[15:8]  
D[7:0]  
TX data is contiguous until the end of the buffer. The buffer may end on a byte boundary. Unused  
bytes at the end of the packet will not be sent to the MIL for transmission.  
The Buffer End Alignment field in TX command ‘A’ specifies the alignment that must be maintained for  
the associated buffer. End alignment may be specified as 4-, 16-, or 32-byte. The host processor is  
responsible for adding the additional data to the end of the buffer. The hardware will automatically  
remove this extra data.  
3.14.3.1  
TX Buffer Fragmentation Rules  
Transmit buffers must adhere to the following rules:  
„
„
„
Each buffer can start and end on any arbitrary byte alignment  
The first buffer of any transmit packet can be any length  
Middle buffers (i.e., those with First Segment = Last Segment = 0) must be greater than, or equal  
to 4 bytes in length  
„
The final buffer of any transmit packet can be any length  
Revision 1.5 (07-18-06)  
SMSC LAN9215I  
DATA4S8HEET  
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