(MPC5674F) How to normally allocate all program variable data to external memory?

chunghohwang — Mon, 28 Aug 2017 05:53:51 GMT

Development environment:
- Code Warrior IDE version 5.9.0

I am developing using the MPC5674F. The target board is equipped with external memory (SRAM).

In order to allocate all program variable data to external memory (SRAM), I modified the code in the LCF file as follows:

* File name : MPC5674F_MVx264.lcf

MEMORY
{
......
// Add External Memory area
EXSRAM : org = 0x20000000, len = 0x001FFFFF
}

SECTIONS
{
......
// Delete program data allocation default code
/*
GROUP : {

.__uninitialized_intc_handlertable ALIGN(20) : {}

.data : {}
.sdata : {}
.sbss : {}
.sdata2 : {}
.sbss2 : {}
.bss : {}
} > internal_ram
*/

// Add program data allocation code

GROUP : {

.__uninitialized_intc_handlertable ALIGN(20) : {}

.data : {}
.sdata : {}
.sbss : {}
.sdata2 : {}
.sbss2 : {}
.bss : {}
} > EXSRAM

.......
......

}

And then, I modified the code to do setting EBI (External BUS Interface) as follows.

* File name : __PPC_eabi_init.c

asm void __init_user(void)
{
.....
.....
// Call SetExternalBusInterface() function for External Bus Interface initialization
bl SetExternalBusInterface

frfree
blr

}

After, The build was done well and I confirmed that variables are allocated in the external memory (SRAM) using the debugger and map file.

However, the variable values was not initialized and the garbage value was stored.
I want to know what's wrong.

How to normally allocate all program variable data to external memory?

Re: (MPC5674F) How to normally allocate all program variable data to external memory?

davidtosenovjan — Tue, 29 Aug 2017 10:13:00 GMT

Hi, linker file modification seems to be right, what I am not sure if it is correct, is EBI initialization in Codewarrior template.

Try to use External_SRAM_init function I have written in following example code in main file:

Example XPC567XFKIT PinToggleStationery CW210

Hope it helps

topic (MPC5674F) How to normally allocate all program variable data to external memory? in MPC5xxx

(MPC5674F) How to normally allocate all program variable data to external memory?

Re: (MPC5674F) How to normally allocate all program variable data to external memory?