IMX6UL DDR3 stress test fails

[Finn0514]

Test software version: ddr stress tester v3.00

I failed to perform DDR calibration, but I can directly overclock the test, why?

The error information is as follows

============================================
        DDR Stress Test (3.0.0)
        Build: Dec 14 2018, 14:13:14
        NXP Semiconductors.
============================================

============================================
        Chip ID
CHIP ID = i.MX6 UltraLite(0x64)
Internal Revision = TO1.2
============================================

============================================
        Boot Configuration
SRC_SBMR1(0x020d8004) = 0x00002092
SRC_SBMR2(0x020d801c) = 0x01000041
============================================

ARM Clock set to 528MHz

============================================
        DDR configuration
DDR type is DDR3
Data width: 16, bank num: 8
Row size: 14, col size: 10
Chip select CSD0 is used
Density per chip select: 256MB
============================================

Current Temperature: 42
============================================

DDR Freq: 396 MHz

ddr_mr1=0x00000000
Start write leveling calibration...
running Write level HW calibration
  MPWLHWERR register read out for factory diagnostics:
  MPWLHWERR PHY0 = 0x0000000f


HW WL cal status: no suitable delay value found for byte 1
Write leveling calibration completed but failed, the following results were found:
    MMDC_MPWLDECTRL0 ch0 (0x021b080c) = 0x001F0000
Write DQS delay result:
   Write DQS0 delay: 0/256 CK
   Write DQS1 delay: 31/256 CK


Error: failed during write leveling calibration

This board can work normally, and the function is very normal, but the verification failure, can you point out, thank you

[Rita_Wang]

When you do the DDR calibration have you used the proper parameters? Your system can work well means that the DDR work well too.

[Finn0514]

The parameters used in calibration are the same as in normal operation, if the parameters are wrong then the system should not work properly?

[Rita_Wang]

Yes, you are right.

[Finn0514]

So why did my calibration fail? Was it my hardware? What should I do to make the calibration work?

[Rita_Wang]

Strongly recommend you to use the proper parameters and go to do the DDR stress test, although system can work but can not sure it will be work well all the time.

[Finn0514]

I mean, after successful calibration, I can adjust several parameters, which can make my ddr work better, but now I have failed to calibrate, so I can't change the parameters. What should I do if I want to calibrate successfully?

[Rita_Wang]

You can refer to this thread:

https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/i-MX-6-7-Series-DDR-Tool-Release/ta-p/12...

[Finn0514]

Thank you, I changed the software version 2.7 and the calibration was successful, but when I stress tested imx6ull, the ddr frequency was 250MHZ and 264MHZ, the test failed, but everything else was successful in the 200-500MHZ range, why?