Hi,
No, it is no necessary to work with a RTOS, however it is easier to manage both cores using the RTOS.
Please check the below document
https://community.nxp.com/docs/DOC-330811
In addition I suggest to check the application note AN11177 Inter Processor Communication,
AN11177: Inter Processor Communications.
this appnote provides information about:
- The API implementation for dual core communication on LPC43xx targets
- How to include or exclude functionality by means of a platform-wise configuration file
- System level settings and debug options to be aware of when changing the
configuration
Regards
Soledad