Programming and debugging: External Flashes

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Programming and debugging: External Flashes

Contributor II

Hi all,

I'm looking for some sort of tutorials on how to work with an external flash.

I've designed a custom board utilizing the I.MXRT633S processor.
Here I've used Flexcomm-SPI-B to connect to the external Octa-Spi Flash to the processor, just like described by Segger ( or like it has been done for the evaluation board. (


Programming via JLink seems to work, debugging does not work though.
I guess, this is kind of a setup issue.

There are no examples inside the SDK, as there is no evaluation board for the I.MXRT633S but only for the I.MXRT685S.

When comparing with the 685S projects, I'm at least missing a folder containing flash_config.c/h.


Anyway, I would be really happy if someone could provide me a reference on how to set up a project from scratch that makes use of external flash in MCUXpresso.


Thanks && all the best,

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2 Replies

Contributor II

Hi Victor,


this is perfect, thank you very much!

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NXP TechSupport
NXP TechSupport

Hello marvin, 

It's important that in your application you have the flash_config files. These files include the flash configuration block that the ROM bootloader will utilize to communicate with your external memory. You can take as a base the files that we provide within the RT685-EVK SDK, but you will need to make the proper changes to adapt those to the memory that you are using. 

Besides that, you need to verify that you have selected a driver so that the debugger can program the external flash. You can see this in the MCU settings on the properties of your project. 


Also, in the preprocessor settings of your project, it's important to verify that you declared the BOOT_HEADER_ENABLE symbol to 1. 


If you connect the memory to FlexSPI port B, you must configure the ISP pins properly.