"Out of variable data space." after changing controller from 5750 to 6750

Question

Hi,
I'm pretty new in working with rabbits and I have to get some code running on a rcm6 750 which was written for a rcm 5750. I changed already compiler settings for seperated data spaces. But it doesn't work.
Found these pdf http://ftp1.digi.com/support/documentation/0220091_b.pdf
with some "solutions". Would like to understand why this error appears and how to fix. Not just get a solution, use it without knowing what i did.

Thanks for your help.

Answer 1

Hard to say without knowing more about your code. Maybe if you shared a MAP file from the 5750 compilation?

I think the RCM5750 was 512K code and 128K data and the RCM6750 is 1MB code and 1MB of data, so there should be plenty of space available. It's likely an issue with how the compiler is splitting up the first 64KB of address space.

Printing the output of basic_program_stats() from mem.lib will give you an idea of how much space the compiler allocates for each type of data.

If you have some large arrays or data structures, consider moving them to "far" memory to reduce the amount of space necessary for root variables (data).

Answer 2

using far and sizing the rootspace to 0x06 worked. Now I can run the code but can't receive Ethernetmessages... lets search again.

Answer 3

I had similar problem on RCM6700.
First of all you could try to separate the instruction & data space, in compiler options.
Than define in the compiler : ROOT_SIZE_4K = 4

You should first try with 5, if its not enough, use 4 as I do.