Memory allocation Issue

Me. Me. 12 days ago

Hi all!
When we used malloc of size 2**15 in C code, it does not allocate.

uint16_t *out = (uint16_t *)malloc(samples_size * sizeof(uint16_t));
if (!out) {
fprintf(stderr, "Memory allocation for out failed.\n");
exit(1);
}
unsigned int samples_size = 1 << 15;

DTCM 256kb and also ITCM in our chip (ARM Cortex M7) is 256kb.

CM7_DTCMCR
x 0xE000EF94
0xE000EF94: 0x00000049

CM7_ITCMCR
x 0xE000EF90
0xE000EF90: 0x00000049

It seems that I cannot use all 256kb that I have in DTCM.
Can you give me insights through this?

Based on ARM support, I have to located this (via scatterloading region ARM_LIB_(STACK)HEAP), but I do not know how to do it?
Appreciate your kind support and assistance.

Top replies

Stephen Theobald 10 days ago in reply to Me. Me. +2 verified

Hi again As a quick test, I added your scatter file above into the "startup_Cortex-M7_AC6" example. With some tweaks, I was able to get the example basically working. Note that the default C library itself...
Ronan Synnott 5 days ago in reply to Me. Me. +2 verified

CMSIS Packs typically provide referenc scatter files for the device used, but you can of course edit as appropriate, for example to locate the stack/heap in the DTCM rather than general memory.
Me. Me. 10 days ago in reply to Stephen Theobald +1

Thank you Stephen It was a great help! The issue is resolved.