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.
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:
- 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 thees_fifo_full
flag. - Once the
es_fifo_full
flag is asserted, de-assert thees_fifo_request
input. - Begin reading the data through the added
es_fifo_* AXI4S
interface. - Once the
es_fifo
is completely drained, thees_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.