Reserve RAM space

Michael Hansen

Prodigy 180 points

Other Parts Discussed in Thread: MSP430F2272

MSP430F2272

How do I reserve 512B of RAM 0x0200 to 0x0400 , I have to store a hole flash segment. ?

I have tried to use linker but I did not get it to work.

I use IAR compiler

over 13 years ago

0 old_cow_yellow over 13 years ago

Guru 58965 points

You must be a c programmer. But why must it be 0x0200 to 0x0400?

Just declare an array of 512B at 0x0200. Tell the compiler that it is static, volatile, and __no_init.

0 Michael Hansen over 13 years ago in reply to old_cow_yellow

Prodigy 180 points

Ok, like this ?

#pragma location = 0x0200

static unsigned char array[512];

0 Katie Pier over 13 years ago in reply to Michael Hansen

TI__Guru* 80181 points

Hi Michael,

As old_cow_yellow mentioned, you don't usually need to know exactly what address in RAM is being used for your array - so you can just follow his suggestion (which is the easiest). However, if you really want to do this for some reason, you'll have to modify your linker file - you can see this earlier forum post which tells how to do it in CCS or IAR: http://e2e.ti.com/support/microcontrollers/msp43016-bit_ultra-low_power_mcus/f/166/p/179005/644816.aspx#644816

Regards,

Katie

0 old_cow_yellow over 13 years ago in reply to Michael Hansen

Guru 58965 points

like:

#pragma location = 0x0200

__no_init static unsigned char array[512];

0 TonyKao over 13 years ago in reply to old_cow_yellow

Genius 3770 points

For IAR you can also do

__no_init static unsigned char array[512] @ 0x0200;

But going back to why you'd want to do this; if you want to store a whole flash segment, then it shouldn't matter where you'd like to store it in RAM. You can still reference a linker mapped array using pointers, and you can do memcpy() and other kinds of data processing.

Absolute addressing should really only be used for memory mapped devices and registers.

Tony

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Reserve RAM space