DSPI EDMA not working with external flash

[zahidul3]

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.

[zahidul3]

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.

[Pavel_Hernandez]

Hello,

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

Best regards,
Pavel

[zahidul3]

Hello,

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

[Pavel_Hernandez]

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

[zahidul3]

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.

[Pavel_Hernandez]

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

[zahidul3]

We are using the MK82FN256 MCU. 

[Pavel_Hernandez]

Hello,

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

Best regards,
Pavel

[Pavel_Hernandez]

Hello,

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

Best regards,
Pavel