topic Re: Global Static Variables in ColdFire/68K Microcontrollers and Processors

Global Static Variables

salman83 — Mon, 10 Sep 2012 10:51:21 GMT

Hi,

I encountered a problem while programming the 52259 Demo kit. All my global static variables are initialized to zero even i have explicitly initialized them to their respective values.

Is there anyway so that the explicit values for the variables do not get initialized to zero. I do not want to declare the variables to const.

Regards.

Re: Global Static Variables

CrasyCat — Mon, 10 Sep 2012 12:04:56 GMT

Hello

I assume you intend the download code to the target board and you want to get the initialization values copied from ROM to RAM during application startup. Am I right?

I assume you are using CodeWarrior for MCU V10.x. Am I right?

If this is what you are looking for, I would recommend you to build the "MCF52259_Internal_Flash" configuration.

This build configuration is created automatically when you create your project from the v10.x project wizard.

To make sure you build this configuration:

Click right on the project in the CodeWarrior Project Windows
Select Build Configuration > Set Active > MCF52259_Internal_Flash.
Now Build the project.

This project should generate the required data to get initialization data copied from ROM to RAM at startup.

The whole trick is implemented in the linker file MCF52259_Internal_Flash.lcf.

CrasyCat

Re: Global Static Variables

salman83 — Mon, 10 Sep 2012 12:13:14 GMT

Thanks for the quick reply.

Yes, I am copying from ROM to RAM. But in ROM, my data is initialized to zero.

I already set the active configuration to Flash. My IDE is

CodeWarrior Development Studio for ColdFire Architectures Version 7.2 Build 91218.

Here is my linker script: -

# Sample Linker Command File for CodeWarrior for ColdFire

KEEP_SECTION { .vectortable }

KEEP_SECTION { .cfmconfig }

# Memory ranges

MEMORY {

interrupts (RX) : ORIGIN = 0x00000000, LENGTH = 0x00000400 # 1K Vector

cfmprotect (RX) : ORIGIN = 0x00000400, LENGTH = 0x00000020 # 32 bytes Flash Configuration Settings

flash (RX) : ORIGIN = 0x00000420, LENGTH = 0x0007FBE0 # 512K - 0x420 Flash

ram (RWX) : ORIGIN = 0x20000000, LENGTH = 0x00010000 # 64K RAM

ipsbar (RWX) : ORIGIN = 0x40000000, LENGTH = 0x0001FFFF

}

SECTIONS {

#########################################################

# Vector Section

.vectors : {

___VECTOR_BASE = . ;

vectors.c (.vectortable)

} > interrupts

#########################################################

# ColdFire Flash Configuration Section

.cfm : {

*(.cfmconfig)

. = ALIGN(0x4);

} > cfmprotect

#########################################################

# Code Section

.code : {

startcf.c (.text)

*(.text)

. = ALIGN(0x10);

*(.rodata)

. = ALIGN(0x10);

___DATA_ROM = . ;

} > flash

#########################################################

# Initialized Data Section

.data : AT(___DATA_ROM) {

___BDT_START = . ;

. = . + 512 ;

___BDT_END = . ;

. = ALIGN (0x4);

___DATA_RAM = . ;

___DATA_RAM_START = . ;

___DATA_START = . ;

___sinit__ = .;

STATICINIT

*(.data)

*(.relocate_code)

. = ALIGN (0x4);

___DATA_END = . ;

___SDATA_START = . ;

*(.sdata)

. = ALIGN (0x4);

___SDATA_END = . ;

} > ram

#########################################################

# Uninitialized Data Section

.bss : {

___SBSS_START = . ;

*(.sbss)

. = ALIGN(0x4);

*(SCOMMON)

. = ALIGN(0x4);

___SBSS_END = . ;

___BSS_START = . ;

*(.bss)

*(COMMON)

. = ALIGN(0x4);

___BSS_END = . ;

___DATA_RAM_END = . ;

} >> ram

___FLASHBAR = 0x00000000;

___FLASHBAR_SIZE = 0x00080000;

___RAMBAR = ADDR(ram);

___RAMBAR_SIZE = 0x00010000;

___IPSBAR = ADDR(ipsbar);

___SP_INIT = (___RAMBAR - (___RAMBAR % 4)) + ___RAMBAR_SIZE - 4;

___SP_END = ___SP_INIT - 0x00000400;

___SP_AFTER_RESET = ___RAMBAR + ___RAMBAR_SIZE - 4;

}

Re: Global Static Variables

CrasyCat — Mon, 10 Sep 2012 13:14:20 GMT

Hello

If you are using CodeWarrior for Coldfire V7.2, then you need to build build target INTERNAL_FLASH.

You can select the build target from the combo box on the left of the .mcp window.

The linker file generated by the project wizard for INTERNAL FLASH build target is called MCF52259_INTERNAL_FLASH.lcf.

It contains the appropriate command to generate the initialization data to be copied from ROM to RAM.

Not sure what you did modify in your .lcf file, but you find attached the .lcf file generated by the wizard for a

MCF52259 MCU INTERNAL_FLASH build target.

You may have to modify it to match your own project.

The portion of the file generating the copy down information is encoded in the section .romp.

CrasyCat