i.MX8M mini MSCALE_DDR_Tool - LPDDR4 Stress Test fails

[simon_graeber]

Hi Everyone,

I made a design with i.MX8M mini (MIMX8MM6DVTLZAA) and LPDDR4 (MT53B512M32D2DS-062 AIT:C).

The schematic and the Layout are the same as on the EVK but we use another PMIC.

Now I'm trying to perform a stress test with MSCALE_DDR_Tool.

The calibration seems to work. I get "Success: DDR Calibration completed!!!" but wenn I start the stress test t0.2 fails:

If I perform a manual Write/Read to that address, it works.

I tried to reduce the Clock Cycle Frequency to 800 MHz but then calibration fails with different messages:

============ Step 1: DDRPHY Training... ============
---DDR 1D-Training @800Mhz...
Failed to find sufficient CA Vref Passing Region for CS 0 channel 0
PMU: ***** Assertion Error - terminating *****
[Result] FAILED

============ Step 1: DDRPHY Training... ============
---DDR 1D-Training @800Mhz...
[Process] End of CA training
[Process] End of initialization
[Process] End of read enable training
[Process] End of fine write leveling
[Process] End of read DQ deskew training
PMU: Error: Dbyte 0 nibble 0 rxClkDly passing region is too small (width = 0)
PMU: ***** Assertion Error - terminating *****
[Result] FAILED

Any ideas?

[Yuri]

Hello,

   Please check carefully if board meets requirements of  Hardware Development Guide for the i.MX8Mm,

in particular - DRAM routing recommendations. 

https://www.nxp.com/docs/en/user-guide/IMX8MMHDG.pdf

Have a great day,
Yuri

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[simon_graeber]

Hi Yuri,

we copied the EVK schematic and Layout so we should actually meet all requirements of the HWDG.

If there are any design problems in the layout, the LPDDR4 should work with lower speed.

How can I perform a test with 800MHz? What does the mentioned ERROR message mean?

I changed "Clock Cycle Freq (MHz)" to 800MHz in the Excel File "MX8M_Mini_LPDDR4_RPA_v11.xlsx" and modified the "TBD" field in the .ds file

"memory set    0x30360054    32    0x0012C09"

Do I have to adjust any other values to run the LPDDR4 with 800MHz?

[simon_graeber]

Ok, I found the problem.

MT53B512M32D2DS-062 AIT:C                Dual-Channel, Dual-Rank

MT53D512M32D2DS-053 WT:D                Dual-Channel, Single-Rank