Honored ContributorHello,
I am looking for a possibility to dynamically allocate memory in OnChip-RAM, while heap is in external RAM. Has anyone experiences regarding this topic?
Honored ContributorBasically no, if You're talking about malloc(). Why not to use direct addressing?
Honored ContributorYes Socrates, I'm talking about malloc().
The thing is, that I want to improve the LwIp-Stack and there some structures (e.g. ethernetif, pbuf) allocated dynamically. As a workaround I did allocate the memory statically, but I think for a better structural design it would be nicer to allocate those structures dynamically at internal RAM. Maybe a solution could be to reassign the heap to internal RAM, then malloc(), and then put the Heap back to external RAM. But the LwIp malloc-function saves and uses the lowest free block for allocation, which is always in external Ram. Sure, I know that I could write my own malloc(), but I wanted to know if someone knows an easier or more common way.Honored ContributorFor embedded use it is actually better to avoid malloc() - except maybe at startup. That way you don't suddenly run out of memory in some important code path.
Honored ContributorOr suffer from memory fragmentation. In my experience you have to be VERY careful with dynamic memory allocation in embedded applications.
