Arria v gt 9.8 gbps – Altera CPRI IP Core User Manual
Page 195
Appendix E: Delay Measurement and Calibration
E–17
Single-Hop Delay Measurement
December 2013
Altera Corporation
CPRI MegaCore Function
User Guide
Arria V GT 9.8 Gbps
Arria V GT 9.8 Gbps variations use a soft PCS, and are a special case. The following
sections describe the Tx delay through this variant.
Figure E–6
shows the Tx path delay components in a CPRI IP core variation that
targets an Arria V GT device and was originally configured with the CPRI line rate of
9.8 Gbps. This figure also illustrates the Tx path delay components in Arria V GT
variations whose CPRI line rate was auto-negotiated down from the configured CPRI
line rate of 9.8 Gbps to a lower line rate.
The Tx path delay from the AUX interface comprises the following delays:
1. Fixed delay from the Aux interface through the CPRI low-level transmitter to the
transceiver PCS. This delay is 7
cpri_clkout
clock cycles.
2. Delay through the transceiver. This delay has the following components.
a. Variable Tx bitslip delay in CPRI RE slaves.
b. Fixed delay through the soft PCS.
c. Variable delay through the Tx buffer between the soft PCS and the PMA.
d. Fixed delay through the PMA configured with the Altera Native PHY IP core.
Fixed Tx Core Delay Component
This delay is 7
cpri_clkout
clock cycles.
Delay through the Transceiver
The following sections describe the delays through the transceiver.
Variable Tx Bitslip Delay
This delay does not exist for CPRI IP cores in master clocking mode. Refer to
for information about
tx_bitslip
.
Transceiver Fixed Delay
This delay is the sum of the fixed delay through the soft PCS and the fixed delay
through the PMA. This delay is shown in the last column of
Table E–7 on
page E–16
.
Figure E–6. Tx Path Delay to CPRI Link in Arria V GT Variations Configured with a CPRI Line Rate of 9.8 Gbps
AxC IF 0
AxC IF n
...
AUX Interface
Data Channels
Transmitter Transceiver
Transmitter
tx_dataout
Physical Layer
CPRI MAP
Interface Module
AUX
Module
(1)
(1)
(2a)
(2b)
(2c)
(2d)