Using TWR-MEM with MQX/TWRK60N512

[Akshaya_Mukund]

I am trying to increase the heap memory available to me in my application, for which purpose I got a TWR-MEM.

For places where I want to use a different memory pool (the one from the TWR-MEM) I used the _mem_create_pool() with the External MRAM Base and Size as arguments.

_mem_pool_id    _MRAM_pool_id;

void mram_create_pool()

{   

_MRAM_pool_id = _mem_create_pool(BSP_EXTERNAL_MRAM_RAM_BASE, BSP_EXTERNAL_MRAM_RAM_SIZE);   

if(_MRAM_pool_id == NULL)   

{    

  _task_block();   

}

}

I then use the function as shown below for mallocs on the External SRAM

pointer mram_alloc(int mem_size)

{

return _mem_alloc_from(_MRAM_pool_id, mem_size);

}

The code I am using was something I got off the forum. (and thank you to the one who posted this)

The problem I am facing is that everytime I called the mram_alloc I end up with the hard-fault which is triggered by the _lwmem_alloc_internal() funciton in lwm_alli.c.

I feel I am doing something fundamentally wrong here. If anyone has any pointers I would appreciate it.

Thanks

[DavidS]

Hi Akshaya,

I started with the mqx/examples/hello project and have attached the modified code.

I use the TWR-MCF52259 and the TWR-K60N612 kits with the TWR-MEM card that has MRAM.

I was able to create a second memory pool in the MRAM.  I then write to a block of MRAM and then read it back.

I did have to update the CW10.2 *.mem file to allow the debugger to have access to the MRAM space.

With the MCF52259 I had to also update the MQX to disable the watchdog in the twrmcf52259.h

           #define BSP_WATCHDOG_DISABLED 2   //DES was 0...set to 2 to disable core watchdog

Lastly I did slow down the K60 flexbus timing by adding wait states in the init_hw.c of the twrk60n512 folder.

FB_CSCR_WS(6) |          //<-- new value

//DES FB_CSCR_WS(2) |  <-- old value

Hope this helps.

Regards,

David

[Akshaya_Mukund]

Hi David,

The code you shared works fine. My use case however is different. I have got multiple tasks running for one. What I notice is that whether I create my memory pool before the tasks are created or if I create the memory pool for a particular task, the data at that memory pool is blank when control goes to another task.

The moment a memory pool is created there is a linked-list of available memory in that pool that is created along with a tag that indicates that the pool is valid. The moment I move into the say the first task  (given that I create the memory pool outside) however the contents of that memory pool are now blank (all zeroes) and so all mallocs then fail as a result since the memory is deemed to be invalid. Any pointers ?

Regards,

Akshaya

[DavidS]

Hi Akshaya,

Can you simplify your app and post the file?

Regards,

David

[Akshaya_Mukund]

Hi David,

I tried using the code you shared (FYI the IDE I m using is Keil MDK). There doesn't seem to be any problem right until the point wherer the malloced memory is either writted or read. A hard_fault is triggered and program crashes. Any pointers ?

I wanted to know if the MQX_USE_LWMEM_ALLOCATOR macro is set to 0 or 1 in your setup.

Also do any switch settings need to be modified on the TWR-MEM. The only TWR-MEM specific changes I have done till now (in MQX) is to uncomment

#define BSP_EXTERNAL_MRAM_RAM_SIZE ((uint_32)__EXTERNAL_MRAM_RAM_SIZE)

in twrk60n512.h and rebuild my libs.

Also is there any need to do a _mem_extend anywhere to extend the existing memory pool.

[DavidS]

Hi Akshaya,

Mine is #define MQX_USE_LWMEM_ALLOCATOR 1  .

I'm attaching picture of my TWR-MEM Rev B. 

The CPU and serial card jumpered per the "MQX3.8/doc/FSL_MQX_getting_started.pdf" section 7. 

I haven't tried the _Mem_extend pool but will add that to my to-do list.

Regards,

David