About behavior of MPU and ADMA2

[Takashi_Kashiwagi]

Hi

I am using MCUXpresso IDE and IMXRT1050-EVKB.

I found the following strange MPU and ADMA2 behavior.

- When OCRAM is not Shareable(Default setting by SDK), f_mount(FATFS) faild.

The cause was due to ADMA2 accessing variables located in OCRAM. 

Strictly, the first access successed (Single Read Sector 0) and the second access failed(Single Read Sector 8192), but ADMA2 returned no error.

The solution is to make shared memory accessible by ADMA 2.

Is this a specification?

SDK Archive Detail is following.

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Build Date: 2018-08-06, Board: EVKB-IMXRT1050

OS: Windows, Toolchain: MCUXpresso IDE

Components: CMSIS DSP Library, Amazon-FreeRTOS Kernel, DMA Manager, lwIP, sdmmc stack, mbedtls, FatFS, USB stack

SDK Version: KSDK 2.4.2 (2018-08-02)

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[Yuri · Accepted solution]

Hello,

     Look at section 4 (Cache maintenance and data coherency) of 

AN12042 app note  (Using the i.MXRT L1 Cache).

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

Have a great day,

Yuri

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[Takashi_Kashiwagi]

Thank you for your reply.

I read AN12042.pdf. Although the clear behavior of ADMA 2 was not described, I thought it was the influence of L1 Chache.

Have a nice weekend.