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September 8, 2025
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STM32Mp257 - DDR4 configuration for swizzle bit

  • September 8, 2025
  • 1 reply
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Hi Community,

I am working with an STM32MP257  interfaced with 16 bit DDR4 of 2 number (16 bit  * 2  = 32 bit = 1 word). I would like to clarify whether the swizzle bit register values actually affect the DQ pin bit-swapping in hardware.

If they do, I need some guidance on how to determine the correct swizzle bit register values. Are there specific calculations or methods recommended for this ?

I have attached my schematic showing the DQ bit swapping with the processor. Any assistance or reference material would be greatly appreciated

Thank you in advance!!

Best answer by Erwan SZYMANSKI

Hello @Vijay_V2225 ,
Did you already check this DDR configuration Application Note : https://www.st.com/resource/en/application_note/an5723-guidelines-for-ddr-configuration-on-stm32mp2-mpus-stmicroelectronics.pdf ? 

I think it can give you great inputs for all the questions you have concerning DDR configuration.

Kind regards,
Erwan.

1 reply

Erwan SZYMANSKI
Erwan SZYMANSKIBest answer
Technical Moderator
September 8, 2025

Hello @Vijay_V2225 ,
Did you already check this DDR configuration Application Note : https://www.st.com/resource/en/application_note/an5723-guidelines-for-ddr-configuration-on-stm32mp2-mpus-stmicroelectronics.pdf ? 

I think it can give you great inputs for all the questions you have concerning DDR configuration.

Kind regards,
Erwan.

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Associate
September 10, 2025

@Erwan SZYMANSKI Thanks for the reply.