nRF Connect SDK Lazy SD Card initialize to startup as fast as possible

[Woo-chan Kim]

Hello!

I'm using nRF5340 MCU with nRF Connect SDK 2.3.0

In my project, I'm using below functions

* MCUBoot

* BLE

* DFU with SMP

* USB MSC

* Filesystem - FATFS

I want to make nRF5340 start as fast as possible.

In my test, SD Card related functions makes about 2s delays.

that functions lists below

* SDMMC - With SPI 25M SDCard SDIO 2.0 64Gbit NAND

* Filesystem - FATFS

* USB MSC

Could you tell me how to initialize SD Card related function after main() function is start.

if there are another method to start fast please tell me.

thanks!!

[Raoul]

Hi,

I think you're right in blaming this on the SD Card initialization.

if there are another method to start fast please tell me.

I discovered this issue which I think could be the cause: https://github.com/zephyrproject-rtos/zephyr/issues/55769

It is fixed by this pull request: https://github.com/zephyrproject-rtos/zephyr/pull/56030

The pull request was first included in NCS v2.4.0 from what I can see. If you are able, could you upgrade your project to NCS v2.4.0 or v2.4.1? If not, try to patch your NCS v2.3.0 install with the pull request above.

Hopefully this reduces your startup time drastically.

Best regards,

Raoul