topic Re: QD4 EEPROM Emulation in 8-bit Microcontrollers

QD4 EEPROM Emulation

abicash — Fri, 27 Feb 2009 15:23:50 GMT

Hello

I am trying to write some 70 bytes into the flash of QD4 during run time.

I have 256 bytes of RAM, most of it is allocated. Although can spare a good amount for stack.

What do you think is the chance of achieving this in such kind of setup?

I understand that Flash erase and Write functions have to be copied in RAM and run from there.

Further I am intending to compare this block of data (written as a constant in Flash) with actual data arriving in RAM.

I need to know the feasibilty for this with 256 bytes on hand.

I really dont have any other choice than QD4,so can't use other devices.

Please provide some comments/pointers/anything as usual.

Thanks and regards

Re: QD4 EEPROM Emulation

celsoken — Fri, 27 Feb 2009 21:20:14 GMT

Dear Abicash,

I remember that DoOnStack has a small footprint and maybe it suits your application.

If you cannot find the updated version I can send you a 4-yr old QG8 implementation.

Cheers,

Celso

Re: QD4 EEPROM Emulation

abicash — Fri, 27 Feb 2009 21:27:58 GMT

Hello celsoken

Thanks for reading and replying .Much appreciated

Yes I found the things...And I wrote the code.

But I am finding a problem of stack and the data overwriting themselves.

I have to sacrifice around 50 bytes for Flash writing and erasing.Is your code in RAM lesser than this?

If it is then I would love to see the code.

Thanks and regards

Re: QD4 EEPROM Emulation

bigmac — Sat, 28 Feb 2009 01:26:07 GMT

Hello,

The following recent thread may be of interest -

http://forums.freescale.com/freescale/board/message?board.id=8BITCOMM&thread.id=13469

The RAM requirement is 10 bytes for the RAM resident function. The code shown is for QG8, but could be adapted for QD4. The RAM function is copied from flash, starting at the bottom of the stack, with the stack pointer initialised to the top of RAM.

Regards,

Mac

Re: QD4 EEPROM Emulation

celsoken — Sun, 01 Mar 2009 02:35:21 GMT

Dear Abicash,

Sorry but I just saw your message, sometimes my email server deletes non-spam msgs.

I am not sure about the footprint, but it could come close to your 50 bytes, anyway it is far beyond 10-bytes Mac´s solution.

Cheers,

Celso

Re: QD4 EEPROM Emulation

abicash — Mon, 02 Mar 2009 14:49:48 GMT

Hello Celso and Bigmac

Thank you both for your interest in my problem.Much appreciated.

As usual Bigmac is the 'Man of Miracles'

I have only seen the code that Bigmac's talking about.

I will implement it soon.Only editing prm file will do with Bigmac's code?

Although I have been able to run my existing code with a little modification to

my prm file and i don't have any overwriting now.

Thanks and regards..