FS_Nano33BLE library 
How To Install Using Arduino Library Manager
Features
This library is just a simple LittleFS/FATFS wrapper to facilitate your usage of LittleFS/FATFS for the onboard flash on MBED nRF52840-based boards such as Nano_33_BLE, Nano_33_BLE_Sense, using Arduino-mbed mbed_nano core
The filesystem access uses normal POSIX APIs or mbed FileSystem APIs
Currently supported Boards
- MBED nRF52840-based boards such as Nano_33_BLE, Nano_33_BLE_Sense, etc. using Arduino-mbed mbed_nano core
Changelog
Initial Releases v1.0.0
- Initial coding to support MBED nRF52840-based boards such as Nano_33_BLE, Nano_33_BLE_Sense, etc. using Arduino-mbed mbed_nano core
Examples:
Debug Terminal Output Samples
FS_Test on Nano 33 BLE with LittleFS size 256KB
The following is the sample terminal output when running example FS_Test on MBED Nano_33_BLE using LittleFS
Start FS_Test on Nano 33 BLE
LittleFS_Nano33BLE v1.0.0
[LFS] LittleFS size (KB) = 256
[LFS] LittleFS Mount Fail
[LFS] Formatting...
[LFS]
FS Format OK. Mounting
====================================================
Writing file: /fs/hello1.txt => Open OK
* Writing OK
====================================================
Reading file: /fs/hello1.txt => Open OK
Hello from Nano_33_BLE
====================================================
Appending file: /fs/hello1.txt => Open OK
* Appending OK
====================================================
Reading file: /fs/hello1.txt => Open OK
Hello from Nano_33_BLE
Hello from Nano_33_BLE
====================================================
Renaming file: /fs/hello1.txt to: /fs/hello2.txt => OK
====================================================
readCharsFromFile: /fs/hello2.txt => Open OK
Hello from Nano_33_BLE
Hello from Nano_33_BLE
====================================================
Deleting file: /fs/hello2.txt => OK
====================================================
Reading file: /fs/hello2.txt => Open Failed
====================================================
Testing file I/O with: /fs/hello1.txt => Open OK
- writing
64 Kbytes written in (ms) 2461
====================================================
- reading
64 Kbytes read in (ms) 7
====================================================
Testing file I/O with: /fs/hello2.txt => Open OK
- writing
64 Kbytes written in (ms) 2460
====================================================
- reading
64 Kbytes read in (ms) 7
====================================================
Deleting file: /fs/hello1.txt => OK
====================================================
Deleting file: /fs/hello2.txt => OK
====================================================
Test complete