ThreadX and NetX do not use malloc internally and so any heap fragmentation would be be an application problem. If your application mallocs and frees memory regularly but in a systematic fashion you should not have an issue with fragmentation.
WICED generally follows that rule with a few exceptions:
1) Scan results
2) TLS packet processing
3) TLS certificate processing
4) WPS workspace
WICED does not provide an interface to the ThreadX memory management functions however your application is free to include the ThreadX header and use those functions directly.
