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IP100A LF
Preliminary Data Sheet
linked list of frame descriptors called TFDs. The host system creates a list of TFDs in system memory,
where each TFD contains the memory locations of one or more fragments of a frame as shown in Figure
4.
HOST SYSTEM MEMORY
TxDMANextPtr
TxFrameControl
1st TxDMAFragAddr
1st TxDMAFragLen
2nd TxDMAFragAddr
2nd TxDMAFragLen
Last TxDMAFragAddr
Last TxDMAFragLen
1st Data Frag (Buffer)
TFD
2nd Data Frag (Buffer)
Last Data Frag (Buffer)
FIGURE 4: TxDMA Data Structure
The TFD format is covered in the Registers and Data Structures section.
The resulting linked list of TFDs is referred to as the TxDMAList, as shown in Figure 5.
HOST SYSTEM MEMORY
TFD1
TFD2
FIGURE 5: TxDMA List of Two TFDs
March. 30, 2007
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Copyright © 2004, IC Plus Corp.
IP100A LF-DS-R17
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