Teledyne LeCroy QPHY-DDR4 - Manual (Page 72)

Appendix B: Common WaRning Messages
Clock Speed Grade
At the beginning of each run QPHY measures the clock speed. This is used to verify that the appropriate
limit set is being used. The warning message occurs when the measured speed grade is greater than
10% different than the selected speed grade. When attempting to run on saved waveforms, if the
displayed data rate is zero this is an indication that the waveforms were not properly loaded by QPHY.
Figure 66 – Clock Speed Grade Warning
Solution
Check to make sure the appropriate limit set has been selected or if using custom speed grade set the
Custom Speed Grade variable.
Read/Write Burst
At the beginning of each acquisition QPHY will check to see that enough R or W bursts are captured in
the acquisition. This warning appears when less than 10 R or W bursts are not detected. When there are
less than 10 bursts detected the measurements will not have much of a statistical significance. If only R
burst tests are selected than the script will only check for R burst and vice versa with W burst.
Figure 67 – R/W Burst Detection Warning
Solution
Verify that the device has enough DQ and DQS transitions. Either the acquisition length or the burst
density can be increased. To increase the acquisition length, adjust the Clock Period Per Screen Division
variable.
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