V-Series Transceiver PHY IP Core User Guide

ID 683171
Date 7/26/2022
Public
Document Table of Contents

17.9. Transceiver Reconfiguration Controller EyeQ Registers

EyeQ is a debug and diagnostic tool that analyzes the incoming data, including the receiver’s gain, noise level, and jitter after the receive buffer. EyeQ is only available for Stratix V and Arria V GZ devices.

EyeQ uses a phase interpolator and sampler to estimate the vertical and horizontal eye opening using the values that you specify for the horizontal phase and vertical height as described in the Table 328table. The phase interpolator generates a sampling clock and the sampler examines the data from the sampler output. As the phase interpolator output clock phase is shifted by small increments, the data error rate goes from high to low to high if the receiver is good. The number of steps of valid data is defined as the width of the eye. If none of the steps yields valid data, the width of the eye is equal to 0, which means the eye is closed.

When the Bit Error Rate Block (BERB) is not enabled, the sampled data is deserialized and sent to the IP core; the PRBS checker determines the Bit Error Rate (BER). When the BER Block is enabled, the Bit checker determines the BER by comparing the sampled data to the CDR sampled data.

Note: If you are using the EyeQ monitor with DFE enabled, you must put the EyeQ monitor in 1D mode by writing the EyeQ 1D-eye bit. For more information, refer to the Table 328 table . The EyeQ path is designed to measure the sampled eye margin. To estimate the pre-CDR eye opening using the measured eye margin data, you can add 10ps to the measured eye margin value for RX input signals with moderate amounts of jitter which is typical in most data streams.

The following table lists the memory-mapped EyeQ registers that you can access using Avalon-MM reads and writes on reconfiguration management interface.

Note: All channels connected to same Transceiver Reconfiguration Controller IP Core share one set of bit error rate block counters. You can monitor one channel at a time. If Transceiver Reconfiguration Controller is interrupted by other operations, such as channel switching or AEQ, the bit error rate data will be corrupted.
Note: All undefined register bits are reserved.
Table 327.   Eye Monitor Registers
Note: The default value for all the register bits mentioned in this table is 0.
Reconfig Addr Bits R/W Register Name Description
7’h10 [9:0] RW logical channel number The logical channel number. Must be specified when performing dynamic updates. The Transceiver Reconfiguration Controller maps the logical address to the physical address.
7’h12 [9] R control and status

Error.When asserted, indicates an invalid channel or address.

[8] R Busy. When asserted, indicates that a reconfiguration operation is in progress.
[1] W Read. Writing a 1 to this bit triggers a read operation.
[0] W Write. Writing a 1 to this bit triggers a write operation.
7’h13 [5:0] RW eyeq offset Specifies the 6-bit offset of the EyeQ register.
7’h14 [15:0] RW data Reconfiguration data for the transceiver PHY registers.
Note: All undefined register bits are reserved.
Table 328.  EyeQ Offsets and Values
Note: The default value for all the register bits mentioned in this table is 0.
Offset Bits R/W Register Name Description
0x0 [4:3] RW BERB Snap Shot and Reset
Only available when you turn on the Enable Bit Error Rate Block in the Transceiver Reconfiguration Controller IP Core GUI. The following encodings are defined:
  • 2'b00: Reserved.
  • 2'b01: Reset everything, snapshot and counters are reset to 0.
  • 2'b10: Take a snapshot. Copy the counter values into local registers for read access. These values are not updated until another snapshot is taken.
  • 2'b11: Snapshot and reset. Take a snapshot of the counter values. Reset the counters and leave the snap shot untouched.
[2] RW Counter Enable Only available when you turn on the Enable Bit Error Rate Block in the Transceiver Reconfiguration Controller IP Core GUI.

When set to 1, the counters accumulate bits and errors. When set to 0, pauses accumulation, preserving the current values.

[1] RW BERB Enable Only available when you turn on the Enable Bit Error Rate Block in the Transceiver Reconfiguration Controller IP Core GUI.

When set to 1, enables the BER. When set to 0, disables the BER counters and the bit checker.

[0] RW Enable Eye Monitor Writing a 1 to this bit enables the Eye monitor.
0x1 [5:0] RW Horizontal phase Taken together, the Horizontal phaseand vertical height specify the Cartesian x-y coordinates of the sample point on the eye diagram. You can increment through 64 phases over 2 UI on the horizontal axis.
0x2 [5:0] RW Vertical height Taken together, the horizontal phase and vertical height specify the Cartesian x-y coordinates of the sample point on the eye diagram. You can specify 64 heights on the vertical axis.
0x3 [15:4] RMW Reserved You should not modify these bits. To update this register, first read the value of this register then change only the value for bits that are not reserved.
[13] RW 1D-Eye Writing a 1 to this bit selects 1D Eye mode and disables vertical height measurement. Writing a 0 to this bit selects normal 2D Eye measurement mode including both the horizontal and vertical axes. You must use 1D Eye mode if you have enabled DFE.
[12:3] RMW Reserved You should not modify these bits. To update this register, first read the value of this register then change only the value for bits that are not reserved.
[2] RW Polarity 19 Specifies the sign of the Vertical height . When 0, the Vertical height is negative. When 1, the Vertical height is positive.
[1:0] RMW Reserved You should not modify these bits. To update this register, first read the value of this register then change only the value for bits that are not reserved.
0x5 [31:0] R Bit Counter[31:0] Only valid when the BERB Enable and Counter Enable bits are set.

Bit Counter[63:0] reports the total number of bits received since you enabled or reset BER counters. Each increment represents 256 bits.

0x6 [31:0] R Bit Counter[63:32]
0x7 [31:0] R Err Counter[31:0] Only available when the BERB Enable and Counter Enable bits are set. Err Counter[63:0] reports the total number of error bits received since you enabled or reset BER counters.
0x8 [31:0] R Err Conter[63:32]

Refer to Changing Transceiver Settings Using Register-Based Reconfiguration for the procedures you can use to control the Eye Monitor.

19 Writing a 1 to the Enable Eye Monitor register will reset the polarity to be positive.