how configure keil for use from external sram as default heap location

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how configure keil for use from external sram as default heap location

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NXP Employee
NXP Employee
Content originally posted in LPCWare by alireza sd on Sun Apr 27 00:23:07 MST 2014
Hi to all
I am beginner in embedded systems so I need your helps.
Recently I was working on a training project and on it I use from lpc1788 with 2mb * 16bit external ram,i successfully use from external memory as buffer of LCD controller, but i can not configure my compiler to use from it as default heap location(my compiler is keil v5),
Now any one can give me a guide that how can i configure keil for use from external memory as default heap location.
Excuse me for my bad English.
Thanks for your attention.
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NXP Employee
NXP Employee
Content originally posted in LPCWare by xianghuiwang on Fri May 16 17:27:28 MST 2014
Defining __initial_sp, __heap_base and __heap_limit
Home » The ARM C and C++ libraries » Defining __initial_sp, __heap_base and __heap_limi
One of several methods you can use to specify the initial stack pointer and heap bounds is to define the following symbols:
•__initial_sp
•__heap_base
•__heap_limit.
You can define these symbols in an assembly language file, or by using the embedded assembler in C.
For example:
__asm void dummy_function(void)
{
    EXPORT __initial_sp
    EXPORT __heap_base
    EXPORT __heap_limit

__initial_sp EQU STACK_BASE
__heap_base EQU HEAP_BASE
__heap_limit EQU (HEAP_BASE + HEAP_SIZE)
}
The constants STACK_BASE, HEAP_BASE and HEAP_SIZE can be defined in a header file, for example stack.h, as follows:
/* stack.h */
#define HEAP_BASE 0x20100000  /* Example memory addresses */
#define STACK_BASE 0x20200000
#define HEAP_SIZE ((STACK_BASE-HEAP_BASE)/2)
#define STACK_SIZE ((STACK_BASE-HEAP_BASE)/2)
Note
This method of specifying the initial stack pointer and heap bounds is supported by both the standard C library (standardlib) and the micro C library (microlib).
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