Altera 10-Gbps Ethernet MAC MegaCore Function - Manual (Page 147)

9–28 Chapter 9: Interface Signals
10-Gbps Ethernet MAC MegaCore Function User Guide February 2014 Altera Corporation
Figure 9–10 shows the TX timestamp signals for the first type of egress correction field
update, where the residence time is calculated by subtracting 96 bit ingress timestamp
from 96 bit egress timestamp. The result is updated in the correction field of the PTP
frame encapsulated over UDP/IPv4.
Figure 9–10. Type 1 Egress Correction Field Update
Type 1 Egress Correction Field Update, 96b, IPV4
2-step Timestamp Request,Input
tx_egress_timestamp_request_valid
tx_egress_timestamp_request_data[N:0]
2-step Timestamp Return,Output
tx_egress_timestamp_96b_valid
tx_egress_timestamp_96b_fingerprint[N:0]
tx_egress_timestamp_96b_data[95:0]
tx_egress_timestamp_64b_valid
tx_egress_timestamp_64b_fingerprint[N:0]
tx_egress_timestamp_64b_data[63:0]
1-step Timestamp Insert,Input
tx_etstamp_ins_ctrl_timestamp_insert
tx_etstamp_ins_ctrl_timestamp_format
1-step Residence Time Update,Input
tx_etstamp_ins_ctrl_residence_time_update
tx_etstamp_ins_ctrl_ingress_timestamp_96b[95:0]
tx_etstamp_ins_ctrl_ingress_timestamp_64b[63:0]
tx_etstamp_ins_ctrl_residence_time_calc_format
1-step IPv4 and IPv6 Checksum,Input
tx_etstamp_ins_ctrl_checksum_zero
tx_etstamp_ins_ctrl_checksum_correct
1-step Location Offset,Input
tx_etstamp_ins_ctrl_offset_timestamp[15:0]
Offset 1 tx_etstamp_ins_ctrl_offset_correction_field[15:0]
Offset 2 tx_etstamp_ins_ctrl_offset_checksum_field[15:0]
tx_etstamp_ins_ctrl_offset_checksum_correction[15:0]
Ingress Timestamp
Don’t-care
Don’t-care
Don’t-care
Don’t-care
Don’t-care
Don’t-care
Don’t-care
Don’t-care
Don’t-care