DSPI EDMA not working with external flash

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DSPI EDMA not working with external flash

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zahidul3
Contributor III

When sending data with DSPI EDMA from external flash memory address, the display does not work properly, probably a timing issue since QSPI access is slower than internal flash/RAM. 

I am using workaround where if I copy to a RAM buffer before sending to spi dma, then it works fine.

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zahidul3
Contributor III

Using the dspi_edma_b2b_transfer example as a base. If the masterXfer.txData address is from external QSPI memory, if doesn't transfer successfully.

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Pavel_Hernandez
NXP TechSupport
NXP TechSupport

Hello,

I review the example and work as expected, maybe you are missing something in your configuration.

Best regards,
Pavel

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zahidul3
Contributor III

Hello,

Can you share your code snippet and what address are you using as the source of the data(txData)?

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2,964 Views
Pavel_Hernandez
NXP TechSupport
NXP TechSupport

Hello, 

Sorry, I do not explain myself, I refer to the original example, the SPI is working as expected, I suggest reviewing your hardware.

Best regards,
Pavel

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2,958 Views
zahidul3
Contributor III

The hardware is wired correctly, we believe there might be a limitation in the EDMA SPI DMA drivers that it does not support reading from external QSPI flash taking into account extra delay for reading from external memory.

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Pavel_Hernandez
NXP TechSupport
NXP TechSupport

Hello,

There are some devices from NXP that use QuadSPI module, so there are some app notes available that can be useful for QuadSPI development. 

Note: Some of the implementation details and features as described in the app notes will be different for K8x, so please use the K8x reference manual for full details.

AN4777, Using the QuadSPI Module on MPC564xS - Application Note (nxp.com)

Quad Serial Peripheral Interface (QuadSPI) Module Updates (nxp.com)

Using the QuadSPI Module on MPC56xxS (nxp.com)

Best regards,
Pavel

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zahidul3
Contributor III

We are using the MK82FN256 MCU. 

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Pavel_Hernandez
NXP TechSupport
NXP TechSupport

Hello,

thanks for the information, could you elaborate further on your issue or the steps to replay this issue?

Best regards,
Pavel

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3,036 Views
Pavel_Hernandez
NXP TechSupport
NXP TechSupport

Hello,

In order to understand, could you tell me what MCU you have?

Best regards,
Pavel

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