topic Re: How to place an array of constants in a flash? in ColdFire/68K Microcontrollers and Processors

How to place an array of constants in a flash?

Florijan — Sun, 28 Jun 2009 02:15:48 GMT

Hi,

i am using CodeWarrior 6.2. I can't put an array of constants in a flash when using Coldfire V1 mcu. It works very well with 8-bit s08 mcus. Can someone please tell me how to make it work with Coldfire V1 mcus also.

For example, i want these array in a flash:

const char [8][200];

Re: How to place an array of constants in a flash?

pgo — Sun, 28 Jun 2009 08:17:27 GMT

Dear Florijan,

I'm won't pretend to be an expert on the subtities of C constants but I think that a 'definitiion' of a constant array without an initialisation is treated differently to one with. It's treated as a declaration rather than a definition. You are free to define the array in another location - the const qualifier on the declaration appears to be ignored for placement.

If I declare an _initialised_ constant array:

const unsigned char dummy[5] = {1};

it ends up in the ROM area.

However,

const unsigned char dummy[5];

ends up in RAM.

So - either initialise the array or use the @notation to place the array in Flash.

const unsigned char myData[10]@0x1000;

bye

PS. Above tested with CW v6.2.2?

Message Edited by pgo on 2009-06-28 11:19 AM

Re: How to place an array of constants in a flash?

Florijan — Sun, 28 Jun 2009 23:26:18 GMT

Dear pgo,

i have found the solution. The catch was that the const array was put in to the flash correctly while the interface on the left side of a Codewarrior window reported increase in data instead of a code and I was thinking that it is placed in ram. Maybe this is a minor bug. Because it is only the case when using Coldfire V1 processors.

Have a nice day!