Data Sheet

Inline Functions—Ethernet Controller I210
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7.2.2.3.3 MAC (2)
• 1STEP_1588 (bit 1) - Sample IEEE1588 Timestamp and post it in the transmitted packet at the
offset defined by the 1588_Offset field in the TSYNCTXCTL register.
• 2STEP_1588 (bit 1) - Sample IEEE1588 Timestamp at packet transmission in the TXSTMP registers.
Note: The two flags 1STEP_1588 and 2STEP_1588 are mutually.
7.2.2.3.4 DTYP (4)
0011b is the value for this descriptor type.
7.2.2.3.5 DCMD (8)
• TSE (bit 7) - TCP/UDP Segmentation Enable
• VLE (bit 6) - VLAN Packet Enable
• DEXT (bit 5) - Descriptor Extension (1b for advanced mode)
• Reserved (bit 4)
• RS (bit 3) - Report Status
• Reserved (bit 2)
• IFCS (bit 1) - Insert FCS
• EOP (bit 0) - End Of Packet
TSE indicates a TCP/UDP segmentation request. When TSE is set in the first descriptor of a TCP packet,
hardware must use the corresponding context descriptor in order to perform TCP segmentation. The
type of segmentation applied is defined according to the TUCMD.L4T field in the context descriptor.
Note: It is recommended that TCTL.PSP be enabled when TSE is used since the last frame can be
shorter than 60 bytes - resulting in a bad frame if TCTL.PSP is disabled.
VLE indicates that the packet is a VLAN packet and hardware must add the VLAN EtherType and an
802.1Q VLAN tag to the packet.
DEXT must be 1b to indicate advanced descriptor format (as opposed to legacy).
Table 7-35. Transmit Data (TDESD.MAC) Layout
1 0
2STEP_1588 1STEP_1588
Table 7-36. Transmit Data (TDESD.DCMD) Layout
76 5 4 3 2 1 0
TSE VLE DEXT Reserved RS Reserved IFCS EOP