Altera Low Latency Ethernet 10G MAC User Manual
Page 101
Signal
Direction
Width
Description
tx_egress_timestamp_96b_data[]
Out
96
Carries the 96-bit egress timestamp in
the following format:
• Bits 48 to 95: 48-bit seconds field
• Bits 16 to 47: 32-bit nanoseconds
field
• Bits 0 to 15: 16-bit fractional
nanoseconds field
This is required for noting the
timestamp ToD which is of 80-bit
(consisting of seconds and nanosec‐
onds) in the respective field of the
PTP packet. The remaining 16-bit
fractional nanoseconds value, if used,
is for updating the CF (Correction
Field) of the PTP packet.
tx_egress_timestamp_96b_
fingerprint[]
Out
n
n = value of the Timestamp
fingerprint width parameter.
The fingerprint of the transmit frame,
which is received on
tx_egress_
timestamp_request_data[]
. This
fingerprint specifies the transmit
frame the egress timestamp on
tx_
egress_timestamp_96b_data[]
is
for.
tx_egress_timestamp_64b_valid
Out
1
When asserted, this signal qualifies
the timestamp on
tx_egress_
timestamp_64b_data[]
for the
transmit frame whose fingerprint is
specified by
tx_egress_timestamp_
64b_fingerprint[]
.
tx_egress_timestamp_64b_data[]
Out
64
Carries the 64-bit egress timestamp in
the following format:
• Bits 16 to 63: 48-bit nanoseconds
field
• Bits 0 to 15: 16-bit fractional
nanoseconds field
The 64-bit timestamp is required to
update the CF in the PTP header.
Updating the CF is fundamental to
the transparent clock operation.
UG-01144
2014.12.15
IEEE 1588v2 Egress Transmit Signals
5-19
Interface Signals for LL Ethernet 10G MAC
Altera Corporation