Kinetis MicrocontrollersのトピックSpecify static variable location

Specify static variable location

Mike_d — Mon, 03 Dec 2012 22:49:28 GMT

Hi,

Can someone please tell me how to specify the flash location of a const variable for a Kinetis MCU using CW 10.2? I wan't to load a specific 32-bit value at a specific flash location.

Thanks,

-Mike

Re: Specify static variable location

LuisCasado — Mon, 03 Dec 2012 23:29:29 GMT

Hello,

Declare your variable in the source code:

#pragma define_section constdata ".constdata" R

#pragma section constdata begin

int My_variable = 0x55AA;

#pragma section constdata begin

Then you have to edit your linker file, something like:

.constdata :

{

*(.constdata)

.= ALIGN(0x4) ;

} > my_data

And define my_data section on memory, it depends on the device and memory location you want:

MEMORY {

m_interrupts (RX) : ORIGIN = 0x00000000, LENGTH = 0x000001E0

my_data (RX) : ORIGIN = 0x00000800, LENGTH = 0x00000100

m_text (RX) : ORIGIN = 0x00000900, LENGTH = 0x00040000-0x00000800

m_data (RW) : ORIGIN = 0x1FFF8000, LENGTH = 0x00010000

m_cfmprotrom (RX) : ORIGIN = 0x00000400, LENGTH = 0x00000010

}

I hope this helps.

Luis

Re: Specify static variable location

Mike_d — Mon, 03 Dec 2012 23:40:57 GMT

So nothing as simple as:

volatile uint32 my_const @0x4A0 = 0x00C00FAB;

that I used with a ColdFire?

Re: Specify static variable location

carlos_neri — Thu, 06 Dec 2012 21:45:52 GMT

a very similar example like the one Luis provided can be found on this post:

Linking an array to a fixed address

The "@" method is not supported on the ARM compiler on CW.

Re: Specify static variable location

Monica — Wed, 12 Dec 2012 00:41:05 GMT

Mike, how is it going?

Were your doubts clarified?

Regards! :smileyhappy: