nRF51822 Heap Size change from 2048 to 1024

[FU HUNG KWAN]

Dear Sir,

What is effect, if I change the Heap Size from 2048 to 1024 in arm_startup_nrf51.s file?

On my project, my device (nrf51822) connect iphone with ANCS, sometime I find the device nothing response, I am worried the problem is caused by change Heap Size to 1024.

Thanks & kind regards kwan

[Hung Bui]

Hi Kwan,

Do you use any dynamic memory allocation (malloc, realloc) in your firmware ? If you don't I don't think reducing the size of the heap could affect the operation.

Could you add a break point in the assert handler and try to find the error code, line number and file name of the function causing issue ?

[FU HUNG KWAN]

Hi Sir,

we do not use "any dynamic memory allocation" in the project.

I also want to set a break point to find out the problem, just the problem should happen during recieve ANCS (iPhone). It is not easy to control the ANCS, because it is sent by iPhone.

Would you let me know how to calculate Software Device use RAM memory?

Thanks & kind regards kwan

[Hung Bui]

Hi Kwan,

You can add a breakpoint in app_error_handler() so that if there is an assertion occurs, you will have the program stop at the handler, and you can find the cause of the assertion by looking at the error code, line and filename.

Could you explain what did you mean by "Software Device use RAM"? If it is the application RAM usage, you can find how much RAM used by each file by looking at the .map file generated in _build folder. Please look for "Execution Region RW_IRAM1" table.

If it's about the Softdevice, it's 8KB RAM used by softdevice, and 2KB for the call stack. So 6KB RAM's left for the application.

[ovrebekk]

If you don't use any dynamic memory you can safely set the heap size to 0. Neither the SoftDevice nor any of the SDK examples/libraries use the heap.