Read DQDQS Training Fail

This section describes the probable reasons for the read DQDQS training failure and the checks required to ensure that the training passes.

Read DQDQS Training Fail—Check 1

Possible Reason

Signal integrity issues on DQ or DQS lines. When check 1 of the Read DQDQS training fails, a dialog box appears as shown in the following figure.

Figure 1. Read DQDQS Training

Graphical user interface, text, application Description automatically generated

Workaround

Configure any one of the following parameters to a different value using the MSS Configurator when check 1 of the Read DQDQS training fails:

Decrease the DQDQS start training window offset value
FPGA DQ ODT
Memory Vref Calibration Value
Memory Pull-Down Drive Strength

The following figure shows the configuration of DQ ODT or DQDQS start training window offset in the DDR Controller tab.

Figure 1. Configuring DQ ODT or DQDQS Start Training Window Offset—DDR Controller Tab

The following figure shows the configuration of pull-down drive strength or Vref calibration value in the DDR Memory Initialization tab.

Figure 2. Configuring Pull-Down Drive Strength or Vref Calibration Value—DDR Memory Initialization Tab

Read DQDQS Training Fail—Check 2

Possible Reason

Signal integrity issues on DQ or wrong start training window offset. When check 2 of the Read DQDQS training fails, a dialog box appears as shown in the following figure.

Figure 1. Read DQDQS Training

Graphical user interface, application Description automatically generated

Workaround

Configure any one of the following parameters to a different value using the MSS Configurator when check 2 of the Read DQDQS training fails:

FPGA DQ ODT
Memory Vref Calibration Value
Memory Pull-Down Drive Strength

The following figure shows the configuration of DQ ODT in the DDR Controller tab.

Figure 1. Configuring DQ ODT—DDR Controller Tab

The following figure shows the configuration of pull-down drive strength or Vref calibration value in the DDR Memory Initialization tab.

Figure 2. Configuring Pull-Down Drive Strength or Vref Calibration Value—DDR Memory Initialization Tab

Read DQDQS Training Fail—Check 3

Possible Reason

Signal integrity issues on DQ or wrong start training window offset. When check 3 of the Read DQDQS training fails, a dialog box appears as shown in the following figure.

Figure 1. Read DQDQS Training

Workaround

Increase the DQDQS start training window offset value when check 3 of the Read DQDQS training fails, see the following figures.

Figure 1. Configuring DQDQS Start Training Window Offset—DDR Controller Tab