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Table 17-10: Transmit Descriptor 2 (TDES2)
Description
Bit
Buffer 1 Address Pointer
These bits indicate the physical address of Buffer 1. There is no limitation on the buffer
address alignment.
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31:09
Table 17-11: Transmit Descriptor 3 (TDES3)
Description
Bit
Buffer 2 Address Pointer (Next Descriptor Address)
Indicates the physical address of Buffer 2 when a descriptor ring structure is used. If the
Second Address Chained (TDES1[24]) bit is set, this address contains the pointer to the
physical memory where the Next descriptor is present. The buffer address pointer must be
aligned to the bus width only when TDES1[24] is set. (LSBs are ignored internally.)
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31:09
Table 17-12: Transmit Descriptor 6 (TDES6)
Description
Bit
TTSL: Transmit Frame Timestamp Low
This field is updated by DMA with the least significant 32 bits of the timestamp captured
for the corresponding transmit frame. This field has the timestamp only if the Last Segment
bit (LS) in the descriptor is set and Timestamp status (TTSS) bit is set.
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31:09
Table 17-13: Transmit Descriptor 7 (TDES7)
Description
Bit
TTSH: Transmit Frame Timestamp High
This field is updated by DMA with the most significant 32 bits of the timestamp captured
for the corresponding receive frame. This field has the timestamp only if the Last Segment
bit (LS) in the descriptor is set and Timestamp status (TTSS) bit is set.
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31:09
Receive Descriptor
The receive descriptor can have 32 bytes of descriptor data (8 DWORDs) when advanced timestamp or IPC
Full Offload feature is selected. When either of these features is enabled, the Software should set Bit 7 of
Register 0 (Bus Mode Register) so that the DMA operates with extended descriptor size. When this control
bit is reset, the RDES0[0] is always cleared and the RDES4-RDES7 descriptor space is not valid.
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Ethernet Media Access Controller
Altera Corporation
cv_54017
Receive Descriptor
17-42
2013.12.30