topic Re: K70 Data memory Relocating to DDR in Kinetis Microcontrollers

K70 Data memory Relocating to DDR

VGS — Fri, 06 Mar 2015 09:26:50 GMT

Hi,

1)I am using Kinetis K70 TWR with codewarrior 10.4 baremetal.

2)I want to load my application code to Flash memory and keep data on DDR only(my data exceeds on chip 128KB RAM)

3) To accomplish above requirment what steps to be followed? Can i get example configuration for the same ?

Thanks

VGS

Re: K70 Data memory Relocating to DDR

kecart — Fri, 06 Mar 2015 12:35:15 GMT

VGS, I am assuming you are trying to get heap memory allocated on your DDR. This is closely related to what I am doing and the answer David Seymour gave regarding external RAM should help you. His answer has an ld file and a small example code file that may help you. I expect you are using the default intflash_ddrdata.ld file which puts your DDR at 0x70000000. Be sure your __EXTERNAL_DDR2_RAM_SIZE is correct for your system if you are working from your own board. Otherwise it should just work. Personally, I use _lwmem_alloc_zero_from(my_pool_id, size) when I want to use the external memory and let the MQS OS functions use the faster internal SRAM. Viewing external RAM as lwmem

Re: K70 Data memory Relocating to DDR

VGS — Sat, 07 Mar 2015 05:38:25 GMT

Hi Kelly

Thanks for the suggestion

Re: K70 Data memory Relocating to DDR

VGS — Mon, 09 Mar 2015 05:48:40 GMT

HI Kelly

Thanks Again for the suggestion. But I am not familiar with MQX .Is there any code example or suggestion about how to achieve this in bare-metal code.

Re: K70 Data memory Relocating to DDR

Carlos_Musich — Wed, 11 Mar 2015 18:22:35 GMT

Hi VGS,

Please take a look to this document Relocating Code and Data Using the CW GCC Linker File for Kinetis

After following the document you will be also able to check the MQX linker file and understand how it relocates data.

Regards,

Carlos