Progress of the FELIX Demonstrator Testing H. Chen, K. Chen, S. - - PowerPoint PPT Presentation

Progress of the FELIX Demonstrator Testing

• H. Chen, K. Chen, S. Tang

August 29, 2019

Progress

• 4 PCBs were received on early July.
• 1 board was assembled at AATech.
• Verified functions:

○ DC-DC modules in 3 power-on stages. ○ PCIe Gen3 bifurcation with x8x8 configurations, and IBERT test for the PCIe bus with PCIe loopback card. ○ Quick test of DDR4. ○ IBERT test for optical modules.

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12-ch FireFly Transmitter (x2) and Receiver (x2) 12-ch duplex FCI/Amphenol OBT module (x2) Finisar BOA has modules with this package 12-ch duplex Finisar BOA 4-ch duplex FireFly module DDR4

Test of the PCIe Bus

• The slot supporting bifurcation for the

test is configured to be x8x8:

• No correctable or uncorrectable error

for both endpoints in one day’s testing.

• IBERT test with PCIe Loopback card

○ PRBS-31, 1E-9 ○ IBERT test for 8 Gbps (PCIe Gen3) ■ For one tested channel: ~24000, 76.47%, w/o DFE (decision feedback equalization). ○ IBERT test for 16 Gbps is run for 3 hours, no error occur for all lanes (with DFE enabled).

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Preliminary Test of the DDR4

Quick test is carried out with speed of 2.1 GT/s. Margin is enough for write and read operations in all Ranks & Bytes.

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Module: A4k16q28bnpbse from ATP

IBERT Test

• All eye diagram scans are configured with with:

○ PRBS-31 ○ BER: 1E-9

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IBERT Test of the 25G Duplex FireFly Module

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9344, 66.67%

4-ch in one module are tested, averaged results:

• Open area: 9632
• UI%: 63.89%
• No special configuration for

the module.

IBERT Test of the 16G FireFly Module

12-ch from one Transmitter module to

• ne Receiver module are tested,

averaged results:

• Open area: 4954
• UI% 54.63%
• No special configuration for the

modules.

• No error for more than 2x1015 bits
• Will ask Samtec to get 25G

modules for testing

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4928, 55.55%

IBERT Test of the 25G Duplex OBT module

20-ch are tested, the averaged results are:

• Open area: 9286.4
• UI%: 61.67%
• No other special

configuration for the module.

• Another 4-ch can run

at 25G once the clock chip is configured.

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9088, 55.56%, CDR is enabled for both TX and RX channels

IBERT Test of the 25G Duplex BOA module

12-ch in one module are tested, averaged results:

• Open area: 7163
• UI%: 48.15
• No special configuration for the

module.

• Looks like the width of eye

diagram is worse than OBT and FireFly

• No heatsink for current test

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7232, 44.44%

Comparison of the Eye Diagram Test Results

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Module Tested Channels Link Speed Open Area UI% Power (W) 4-ch 25G Duplex FireFly 4 25 Gbps 9632 63.89% Nom=1.7 Max=2.5 12-ch 16G FireFly Tx/Rx 12 15.9375 Gbps 4954 54.63% 12-ch 25G Duplex OBT 20 25 Gbps 9286.4 61.67% Nom=5.8 Max=7.9 12-ch 25G Duplex BOA 12 25 Gbps 7163 48.15% Nom=6 Max=7.3

Summary

• The test verified the power scheme on new FELIX demonstrator.
• The stack-up, layout & route work well for 25G+ links.
• The performance of different modules (no special configuration to all

modules) are measured:

○ Preliminary test shows OBT and FireFly have better performance

• Verified bifurcation without PCIe switch
• Quick test shows the DDR4 works well; the margin is enough for the

R/W operations.

• Will continue the test, to verify all functions: e.g. jitter measurement for

clock chips; QSPI multiboot to support selection of different firmwares.

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