F-Tile CPRI PHY Intel® FPGA IP Design Example User Guide

ID 683281
Date 6/21/2022
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2.2.1. Packet Client

The packet client, also known as the pattern generator/checker, is used for the following purposes:
  • Generate CPRI hyperframe at the TX, and check the hyperframe for correctness at the RX.
  • Generate start pulses at the TX, and stop pulses at the RX, for deterministic latency measurement.
There are two types of packet client:
  • XGMII—used for 64b/66b data rates, like 24G, 12G, and 10G.
  • 8B/10B—used for data rates, like 9.8G, 6.1G, 4.9G, 2.4G, and 1.2G
The structure of the generated pattern at TX is a simple hyperframe structure that consists of two parts: the synchronization control word, and the data block. The generated pattern does not contain any other control words as specified in Table 7 of CPRI Specification v7.0, which is useful when decoding the frame at the MAC level.

The hyperframe starts by sending synchronization control words, which is specified in Table 9A of CPRI Specification v7.0 (for XGMII) or Table 9 of CPRI Specification v7.0 (for 8B/10B). Followed by data block, which consists of an incremental pattern from a counter (for XGMII), or PRBS pattern (for 8B/10B). The size of the hyperframe also honors the variable word length that varies with data rate, as specified in Table 3 of CPRI Specification v7.0.

At the RX, the pattern checker receives the hyperframe and determines whether it achieve HFNSYNC according to Figure 26B of CPRI Specification v7.0 (for XGMII), or Figure 26A of CPRI Specification v7.0 (for 8B/10B). Once HFNSYNC is achieved, the pattern checker checks the data pattern at the data block for correctness.

Table 5.  XGMII Pattern Generator Ports
Port Name Width Direction Domain Description
clk 1 Input - Clock. Supply with tx_clkout2.
reset 1 Input async Asynchronous reset. Active high.
cpri_rate_sel 4 Input clk Indicates the current CPRI rate to the block. This port follows the same definition as the F-Tile CPRI PHY Intel FPGA IP.
tx_dataout 64 Output clk TX XGMII data.
tx_ctrlout 8 Output clk TX XGMII control.
start 1 Output clk Start pulse used for deterministic latency measurement.
Table 6.  XGMII Pattern Generator Parameters
Parameter Name Default Value Description
SIM_MODE 0 When enabled, the generated hyperframe size is reduced by a factor of 4 or 64, thereby reducing the simulation time.
  • 0: disabled
  • 1: enabled (reduced by a factor of 4)
  • 2: enabled (reduced by a factor of 64)
Table 7.  XGMII Pattern Checker Ports
Port Name Width Direction Domain Description
clk 1 Input - Clock. Supply with rx_clkout2.
nreset 1 Input async Asynchronous reset. Active low.
cpri_rate_sel 4 Input clk Indicates the current CPRI rate to the block. This port follows the same definition as the F-Tile CPRI PHY Intel FPGA IP.
datain DATA_WIDTH Input clk RX XGMII data.
ctrl 8 Input clk RX XGMII control.
hyperframe_sync 1 Output clk Indicates whether RX has achieved HFNSYNC.
errorflag 1 Output clk Asserted when err_cnt is not 0 and latches until being reset.
err_cnt 5 Output clk Error counter that is incremented by 1 when 1 cycle of received data pattern is mismatched.
stop 1 Output clk Stop pulse used for deterministic latency measurement.
Table 8.  XGMII Pattern Checker Parameters
Parameter Name Default Value Description
SIM_MODE 0 When enabled, this parameter guides checker to look for the correct position in the shorter hyperframe (enabled by similar setting in TX) when searching for the sync control word.
  • 0: disabled
  • 1: enabled (reduced by a factor of 4)
  • 2: enabled (reduced by a factor of 64)
DATA_WIDTH 8 Determines the width of datain.
Table 9.  8B/10B Pattern Generator Ports
Port Name Width Direction Domain Description
clk 1 Input - Clock. Supply with tx_clkout2.
reset 1 Input async Asynchronous reset. Active high.
cpri_rate_sel 4 Input clk Indicates the current CPRI rate to the block. This port follows the same definition as the F-Tile CPRI PHY Intel FPGA IP.
tx_dataout DATA_WIDTH Output clk TX 8B/10B data.
tx_ctrlout DATA_WIDTH/8 Output clk TX 8B/10B control.
start 1 Output clk Start pulse used for deterministic latency measurement.
Table 10.  8B/10B Pattern Generator Parameters
Parameter Name Default Value Description
SIM_MODE 0 When enabled, the generated hyperframe size is reduced by a factor of 4 or 64, thereby reducing the simulation time.
  • 0: disabled
  • 1: enabled (reduced by a factor of 4. Start/stop pulses feature is supported.)
  • 2: enabled (reduced by a factor of 64. Start/stop pulses feature is not supported.)
DATA_WIDTH 16 Determines the width of tx_dataout and tx_ctrlout.
Table 11.  8B/10B Pattern Checker Ports
Port Name Width Direction Domain Description
clk 1 Input - Clock. Supply with rx_clkout2.
nreset 1 Input async Asynchronous reset. Active low.
cpri_rate_sel 4 Input clk Indicates the current CPRI rate to the block. This port follows the same definition as the F-Tile CPRI PHY Intel FPGA IP.
datain DATA_WIDTH Input clk RX 8B/10B data.
ctrl DATA_WIDTH/8 Input clk RX 8B/10B control.
hyperframe_sync 1 Output clk Indicates whether RX has achieved HFNSYNC.
errorflag 1 Output clk Asserted when err_cnt is not 0 and latches until being reset.
err_cnt 5 Output clk Error counter that is incremented by 1 when 1 cycle of received data pattern is mismatched.
stop 1 Output clk Stop pulse used for deterministic latency measurement.
Table 12.  8B/10B Pattern Checker Parameters
Parameter Name Default Value Description
SIM_MODE 0 When enabled, this parameter guides checker to look for the correct position in the shorter hyperframe (enabled by similar setting in TX) when searching for the sync control word.
  • 0: disabled
  • 1: enabled (reduced by a factor of 4. Start/stop pulses feature is supported.)
  • 2: enabled (reduced by a factor of 64. Start/stop pulses feature is not supported.)
DATA_WIDTH 16 Determines the width of datain and ctrl.