I.mx RT1176 M4 core cannot write to OCRAM part of shared memory

[Milan_Ignjatovic]

Hi,

i am working on custom board with Imx RT1176 microcontroller onboard. I am trying to establish communication between cores. My goal is for both cores to be able to read and write in shared memory. IDE is Keil, debugger Ulink2.

I started from SDK example MU communication with interrupt. It works fine.

I have read AN13264 and tried using shared memory to write from M7 and from M4.

When i use CM4 DTCM I can write and read from both cores, but when I try to write to OCRAM only M7 core can write. I can read the data from M4 side, but I cannot write.

I tried disabling bus cache like this thread posted:

https://community.nxp.com/t5/i-MX-Processors/Cortex-M4-bare-metal-application-cannot-read-data-from-...

but nothing changes. 

 What could be the reasons M4 core cannot write to OCRAM part of the shared memory?

Any help is appreciated,

Best Regards,

Milan. 

[Milan_Ignjatovic]

Hi Kan,

i tried writing to OCRAM1, OCRAM2, OCRAM1 ECC and OCRAM2 ECC as those regions are mentioned in AN13264 as typical memory which can be used as shared memory:

OCRAM1: 0x2024_0000

OCRAM2: 0x202C_0000

OCRAM1_ECC: 0x2034_0000

OCRAM2_ECC: 0x2035_0000

Best Regards,

Milan.

[Kan_Li]

Hi @Milan_Ignjatovic ,

Not sure how M7 core communicate with M4 on your side, but if M7 is writing to the RAM, M4 can read but not write in the same time.

Have a great day,
Kan

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[Milan_Ignjatovic]

Hi Kan,

i tried writing to OCRAM1, OCRAM2, OCRAM1 ECC and OCRAM2 ECC as those regions are mentioned in AN13264 as typical memory which can be used as shared memory:

OCRAM1: 0x2024_0000

OCRAM2: 0x202C_0000

OCRAM1_ECC: 0x2034_0000

OCRAM2_ECC: 0x2035_0000

Best Regards,

Milan.

[Kan_Li]

Hi @Milan_Ignjatovic ,

Which OCRAM are you referring to ? Please kindly clarify.

Have a great day,
Kan

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