Now, uCXpresso.NRF provides the free evaluation license on the GitHub

uCXpresso.NRF is a RTOS C/C++ Framework,

Features:

1. Develop on Mac OS/X, Linux and Windows with LPCXpresso IDE (free).
   
2. Multi-Tasking RTOS supported
   
3. Enhanced BLE C++ framework
   
4. Tickless Low Power technology ready. Activity avg. @ 26uA (Min. 6uA)
   
5. Using SoftDevice 7.1
   

Go on the GitHub:https://github.com/ucxpresso/nano51822