topic Re: Problem writting FLASH as an EEPROM in 8-bit Microcontrollers

Problem writting FLASH as an EEPROM

hernanEche — Sat, 31 Jul 2010 02:14:30 GMT

Hello, I did this question

https://community.freescale.com/thread/68126

Then I found AN3824 a library for MC9S08LG32

I am using MC9S08GT32 (LG and GT that's first difference)

then the code I downloaded have a demo that says : "This demo is designed to run only on MC9S08GB60 evaluation board. " I couldn't integrate that to my project there are too many files and things to touch like frecuencies.

A little lost back here for some light.

I am reading this is a very complex thing to do, it need the code to be executed at RAM?

I really would be glad with something like

writeByte2Flash(u08 byte, int address);
u08 readByte2Flash(int address);

Re: Problem writting FLASH as an EEPROM

bigmac — Mon, 02 Aug 2010 10:25:36 GMT

Hello,

The code associated with AN3824 is rather complex because it appears to distribute the parameter storage over a number of flash sectors, presumably to increase the total number of erase/write cycles before flash "wearout" occurs. If your application does not require frequent update of the non-volatile data, you can more simply write the data to a single dedicated sector.

The attached code extensively uses inline assembly, but would generally be applicable to most HCS08 devices, with minor variation, mainly to the PRM file.

You will need to define the bus clock frequency you are using (within the header file) so that the appropriate flash clock frequency is set when FlashInit() function is called. A small RAM based function is used, and the function CopyInRAM() will transfer this code from flash. The RAM block for this code must be defined within the PRM file, as must also the flash block for the non-volatile parameters.

The remaining functions are Flash_Erase() that erases a flash sector, and Flash_Program() that programs a single byte. There is no need for a special read function where variables are allocated within the flash block - simply read the variable in the normal manner.

Regards,

Mac

Re: Problem writting FLASH as an EEPROM

hernanEche — Mon, 02 Aug 2010 20:44:41 GMT

Hello, thanks for the answer! , I will try to make it works

What I made till now:

1-Modify project.prm adding this

SEGMENTS    ..    FLASH_TO_RAM             =  READ_ONLY    0xE000 TO 0xE00F RELOCATE_TO 0x0200;        ..ENDPLACEMENT    ..    FLASH_ROUTINE                       INTO  FLASH_TO_RAM;    ..END

2.Adding .h and .c to project

3.Define BUS_CLOCK in S08_Flash.h

//(in my project)#define BUS_CLOCK 4195200

4. Comment //#include "derivative.h" because this included MC9S08GT32A.h but my project uses MC9S08GT32.h

5.Run!

I watched FLASH memory with "True-Time Simulator & Real Time Debugger" connected to an Open Source BDM and to the microcontroller and..

It works!! I see in FLASH the data I've written..

Now the question is:

The Flash_Read function is missing?, How do I Read FLASH Data from source?

Thank you very much again

Re: Problem writting FLASH as an EEPROM

bigmac — Wed, 04 Aug 2010 02:20:41 GMT

Hello,

Maybe the following function could be used to read a byte from a specific location in (flash) memory -

byte get_mem( const byte *addr)

{

return (*addr);

}

Regards,

Mac

Re: Problem writting FLASH as an EEPROM

hernanEche — Thu, 05 Aug 2010 21:35:08 GMT

Thank you very much!

Re: Problem writting FLASH as an EEPROM

hernanEche — Thu, 23 Dec 2010 20:33:27 GMT

News:

A related error because data overlap

https://community.freescale.com/message/74836#74836

could be easily corrected (I hope) I will try it now

Bye!