.. envvar:: ENABLE_CUSTOM_HEAP
If your application is experiencing heap fragmentation then you can try the alternative heap.
undefined (default)
OFF, use standard heap
1
Use :doc:`UMM Malloc <umm_malloc/README>`.
Warning
Do not enable custom heap allocation and -mforce-l32 compiler flag at the same time.
.. envvar:: UMM_FUNC_IRAM
Default: 1 (enabled)
Custom heap functions are stored in IRAM by default for performance reasons.
If you need the IRAM (about 1.5K bytes) then disable this option::
make ENABLE_CUSTOM_HEAP=1 UMM_FUNC_IRAM=0