How to create a .txt file with nRF52840 and send it through USB to computer

[masterLee]

Hi everyone,

I use nrf52840 DK with Segger embedded studio. I have created a project where I read several sensors data and send these data to mobile through BLE UART.

I also have an external 512MB flash memory chip  where I save all the sampled data, in case I don't have my mobile connected. Since I do not use a file system with

the flash memory chip ( I just save raw data to it and read them back), I need to encapsulate those data in a .txt file after I retrieve them from the flash memory chip

  and then send them through the USB cable to my computer.

How can this .txt encapsulation be done?

  I tried to write to a Hello_World.txt  a simple string but the file is not created. Is it possible to do it with FILE structure somehow?

Thank you

[awneil]

Why does it have to be a file on the nRF ?

Wouldn't it make more sense to just have the nRF send the data, then the phone - which is far better equipped for such things - can put it into a file, if required.

[masterLee]

Yes, your thought is absolutely correct . I just I thought that since I will be using the USB cable,  I could use it to create a file with my data this way.

[awneil]

Which "USB cable" are you referring to - there are two on the DK !

Have you looked at the USB MSC (Mass Storage) example:

https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.sdk5.v15.3.0/usbd_msc_example.html

[masterLee]

Yes you are right. I refer to the nRF USB next to the reset button not the debugger's. No I haven't seen the mass storage example. I will check it out. Thank you

[masterLee]

The usbd_msc example uses the FatFS library to handle files (create, erase etc.)  and  It does not use the stlib.h