IMX1176 Memory Organization

[tbayram]

Hello Everyone,

We are working on a custom board with IMX1176 processor. SDRAM and NOR Flash used on the custom board are different from the ones used on the EVK board. Considering that it will be an extensive project and both M7 and M4 cores will be used, we look at the linker file of one of the sample projects to examine the memory organization. Can someone explain to us why SDRAM, internal RAM and NOR flash are so divided and what the divided areas are used for?

Thank you,
Good work everyone.

[tbayram · Accepted solution]

thank you @kerryzhou. 

I will check document. These asnwers enought for me.

[tbayram]

Hi @kerryzhou,

Actually I have more question about memory organization.

1.Why External SDRAM is separated into Board_SDRAM and NCACHE_REGION. Why do we need NCACHE_REGION?

2.In which cases is ECC required?

3.Which points can I check to see if the DCD configuration matches the external SDRAM we are using?

4.We want to use M4 as a master. İs there any difference in this situation?

5.And in any display project, In which sections do we keep data such as .data, .text, photo?

All of my question is here, Could you reply only this question please?

Thank you again.

[kerryzhou]

Hi @tbayram 

Answer your questions:

1.Why External SDRAM is separated into Board_SDRAM and NCACHE_REGION. Why do we need NCACHE_REGION?

=>Answer: good question, it is determined by the cache, some situation, eg, LCD, SDCARD, USB, even some flexSPI situation, when use the cache in the SDRAM, it will have issues, so need to use the SDRAM when close the cache, more details, please refer to application note:

https://www.nxp.com/docs/en/application-note/AN12042.pdf

2.In which cases is ECC required?

=>Answer: If you don't care about it, you can don't use the ECC.

If you want to use ECC, you can refer to:

https://www.cnblogs.com/henjay724/p/12673731.html

3.Which points can I check to see if the DCD configuration matches the external SDRAM we are using?

=>Answer: Good question, DCD is the semc control, you can check the RM about the DCD, to know the format, you will know which register is controled.

When you change the SDRAM, normally you can run this code:

SDK_2_14_0_MIMXRT1170-EVK\boards\evkmimxrt1170\driver_examples\semc\sdram\cm7

configure the related SEMC interface for the SDRAM.

Then, when you modify the related register, you also can modify that in the DCD area.

4.We want to use M4 as a master. İs there any difference in this situation?

=>Answer: in my memory, need M7 as the master, then communicate with M4, M4 is slave.

Why you need M4 as master?

5.And in any display project, In which sections do we keep data such as .data, .text, photo?

=>Answer: As I reply you, you can  define the user data sector, no matter in the internal RAM, .text, or the SDRAM. then define your photo data to that area.

But, a simple way, just constant data, will put in the text, I mean flash address, that will be OK to use.

Wish it helps you!

Best Regards,

Kerry

[tbayram]

hi @kerryzhou ,

Thanks for your kindly reply.

I have one more question. We want to use M4 as a master. İs there any difference in this situation?

Thank you again.

Have a nice day

[kerryzhou]

Hi @tbayram ,

  As I know, M7 is the master, not the M4.

Best Regards,

Kerry

[tbayram]

And in any display project, In which sections do we keep data such as .data, .text, photo?

[kerryzhou]

Hi @tbayram ,

   for the  .data, .text, photo.

.data, you can defined it to the related internal RAM or the external SDRAM.

text is in the flash area, I mean the flexSPI remap address.

photo, is the user data, you can set it to internal or the SDRAM, just define it to your required data sector.

Wish it helps you!

Best Regards,

Kerry

[kerryzhou]

Hi @tbayram ,

   Thank you for your interest in the NXP MIMXRT product, I would like to provide service for you.

   About the memory organization, in fact, to the different flash and sdram, just the driver have the difference, the memory start area is still the same, just the size is determined by your used SDRAM and flash size .

  About your attached picture, it is the RT1176 memory map, it is determined by the RT1176, you can check RT1176 reference manual:

chapter: 3.2 System memory map (CM7)

ITCM, DTCM, OCRAM is the RT1176 internal RAM.

SDRAM is the semc interface connect to the external SDRAM, so you can find the SEMC address.

Flash is connected to the flexSPI, so it is from 0X30000000.

I think this is enough to help you explain the memory origanization.

To your own used flash and SDRAM, it is the same address, just need the flashdriver, DCD need to match your own used flash and SDRAM.

Wish it helps you!

If you still have questions about it, please kindly let me know.

Best Regards,

Kerry