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/
838
Nations Technologies Inc.
Tel
:
+86-755-86309900
:
Address: Nations Tower, #109 Baoshen Road, Hi-tech Park North.
Nanshan District, Shenzhen, 518057, P.R.China
Bit field
Name
Description
31
IC
Interrupt-on-completion control bit.
This bit is valid after TDES1.LS is set.
0: ETH_DMASTS.TI will not be set when frame transmission is complete.
1: ETH_DMASTS.TI will be set when frame transmission is complete.
30
LS
Last block.
This bit indicates that buffer contains the last block of frame.
0: The descriptor buffer does not contain the last block of frame.
1: The descriptor buffer stores the last block of frame.
29
FS
First block.
This bit indicates that buffer contains the first block of frame.
0: The descriptor buffer does not contain the first block of frame.
1: The descriptor buffer stores the first block of frame.
28:27
CIC[1:0]
Checksum insertion control bits.
00: Do not insert checksum.
01: Only enable calculation and insertion of checksum of hardware IP header.
10: Enable calculation and insertion of checksums of hardware IP headers and data
fields, but do not calculate checksums of pseudo-headers.
11: Enable calculation and insertion of checksum of hardware IP header and data field,
and also calculate checksum of pseudo-header.
26
DC
Disable CRC.
This bit is only valid when TDES1.FS is 1.
0: MAC automatically insert CRC field.
1: MAC does not insert CRC field.
25
TER
Ring transmit end mode bit.
This bit is only used in ring structures and has higher priority than the TDES1.TCH
bit.
0: Current descriptor is not the last of descriptor queue.
1: Current descriptor reaches the last of descriptor queue, and DMA returns base
address of list.
24
TCH
Second address linked list mode bit.
This bit is used in a chain structure. When this bit is 1, the value of these bits in
TDES1.TBS2[10:0] is invalid.
0: Second address in descriptor is the address of second buffer.
1: Second address in descriptor is the address of next descriptor.
23
DP
Disable PAD.
This bit is only valid when TDES1.FS is 1.
0: MAC automatically adds padding bytes to frames whose frame length is less than
64 bytes, and inserts CRC value, ignoring TDES1.DC.
1: MAC does not automatically pad bytes for frames whose frame length is less than
64 bytes.
22
TTSE
Transmit timestamp enable bit.
This bit is only valid when TDES1.FS is 1. When this bit is 1 and