how to increase write latency and read latency of LPDDR4 on 8MPLUSLPD4-EVK?

[jekim]

Hello, 

I'm using IMx8MP excel RPA for changing the conditions. The default values in the RPA are WRITE_LATENCY 8 and READ_LATENCY 14 at 800MHz. I modified it as WRITE_LATENCY 10 and READ_LATENCY 20 in DDRC_DRAMTMG2 register. The latencies in MR2 are connected to the register in the excel sheet. However, the generated .ds file had calibration failure on DDR tool as attached. How can I solve this?

Thanks.

[pengyong_zhang]

Hi @jekim 

Thanks for your advice, But This parameter depends on the frequency of DDR. It is a fixed value. Our DDR fully complies with JDEC standards.  So i think we would not add it to the configuration page.

B.R

[pengyong_zhang]

Hi @jekim 

We strongly recommend that customers do not modify the WL RL, This two parameters will changed follow DDR frequency change.

B.R

[jekim]

Hi @pengyong_zhang ,

Another EVM by different maker allows the latency changes. If possible, please add the option into the config tool.

Thanks.

[pengyong_zhang]

Hi @jekim 

Please share your DDR datasheet and your schematic file.

Also please use the latest DDR Config Tool run the test.

https://www.nxp.com/design/design-center/development-boards-and-designs/i-mx-evaluation-and-developm...

B. R

[jekim]

Hi @pengyong_zhang ,

Config Tool 25.03 doesn't provide 800MHz. So, I have to use excel RPA.

I'm using 8MPLUSLPD4-EVK.  (  i.MX 8M Plus Evaluation Kit | NXP Semiconductors )

the latencies per frequency are as below.

[addiyi]

Hi,

You can change the default data rate from Clock Cycle Freq option

The Preset are the default configuration for NXP EVK boards, from where the configuration can be customized.

Adrian

[jekim]

Hello @addiyi ,

The latest DDR tool show 3 presets for IMX93. "EVK 11x11" has only LPDDR4X not also LPDDR4. Does only "QSB 9x9" support LPDDR4 configuration?

 

Thanks.

[pengyong_zhang]

This just means it is a 9x9 QSB configuration, you just need to configure your LPDDR4X parameters normally

[jekim]

Hello @pengyong_zhang ,

There are two different devices. They are LPDDR4 and LPDDR4X. The 11x11 preset shows only LPDDR4X. How to choose LPDDR4 config for 11x11?

[pengyong_zhang]

Hi @jekim 

As i mentioned before, this choose is just use choose which SOC, you are not need to care about LPDD4 or LPDDR4X, Just configuration your DDR parameters is OK.

[jekim]

Hello @addiyi ,

Thank you. I didn't aware of the new feature to change the clock frequency.

btw, when a preset is selected, how can I change the write latency and read latency?

Thanks.