Sampled Eye Scan Functionality - 1.0 English

Virtex UltraScale+ FPGAs GTM Transceivers Wizard LogiCORE IP Product Guide (PG315)

Document ID
PG315
Release Date
2022-05-04
Version
1.0 English

The Sampled Eye Scan functionality has been added to the GTM Control IP and populates an ES FIFO with equalized ADC samples and loop coefficients used for SNR calculation. Each sample of es_fifo_full from an es_fifo_request contains 1750 data samples with the following data structure as shown in the following table. The Sampled Eye Scan function is shared between 4 GTM_DUALs and only one channel can be serviced at a time.

Table 1. Data Structure
FIFO Location Data Content
1 DUAL/Channel ID
2 Coefficient (H0_P3X)
3 Coefficient (H0_P2X)
4 Coefficient (H0_P1X)
5 Coefficient (H0_0)
6 Coefficient (H0_M1X)
7 Coefficient (H0_M2X)
8 Coefficient (H0_M3X)
9 YK_DATA2[7:0],YKDATA1[7:0]
0 YK_DATA4[7:0],YKDATA3[7:0]
883 YK_DATA1750[7:0],YKDATA1749[7:0]

Instructions on how to use the GTM Sampled Eye Scan feature are as follows:

  1. After GT RXRESET is complete, assert es_fifo_request at any time to initiate a sampled eye scan for a specific DUAL.

    es_fifo_request should stay asserted while monitoring the es_fifo_full flag.

  2. Once the es_fifo_full flag is asserted, de-assert the es_fifo_request input.
  3. Begin reading the data through the added es_fifo_* AXI4S interface.
  4. Once the es_fifo is completely drained, the es_fifo_axis_0_tvalid will go low, thus preventing further reads.

    YK_DATAx are signed values (2s complement); they are not continuous samples. It is just a data set of equalized sampled data and can be plotted directly.

    H0_* - are not necessary to plot the data.

You can acquire additional sampled eye data by repeating the above steps on each of the target required GTs.