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From: Nial Stewart on 22 Jan 2010 08:00
> Can anyone tell how to design a reset circuit for microcontroller that can
> change the default values? example:
> REGISTER DEFAULT VALUES
> program counter 0x43
> stack pointer 0x0f
> accumultor 0x00
> flag register 0x80


If you used a soft core in an FPGA you could probably change these!

For a hard device see the other answers.


Nial.


From: -jg on 22 Jan 2010 16:29
On Jan 22, 2:17 am, "sharathselvam" <sharathsel...(a)gmail.com> wrote:
> Can anyone tell how to design a reset circuit for microcontroller that can
> change the default values? example:
> REGISTER           DEFAULT VALUES
> program counter    0x43
> stack pointer      0x0f
> accumultor         0x00
> flag register      0x80

Sure. Not difficult.

Get the Debug-Interface information (Contact the vendor, or reverse
engineer a working system, or some even publish it).

You can then use that Debug channel, to change the internal values to
whatever values you want, and to the user code that follows, it will
look exactly like it came out of reset with those new default values.

Expect an 'A' for this answer, as it is unlikely any of your
classmates will answer the exact question asked.

-jg
From: StoneThrower on 22 Jan 2010 17:17
> Can anyone tell how to design a reset circuit for microcontroller that can
> change the default values? example:

I know that one. Gimme a next question.

--
StoneThrower
www.dgmicrosys.com

From: bigbrownbeastie on 23 Jan 2010 04:05
On Jan 21, 1:17 pm, "sharathselvam" <sharathsel...(a)gmail.com> wrote:
> Can anyone tell how to design a reset circuit for microcontroller that can
> change the default values? example:
> REGISTER           DEFAULT VALUES
> program counter    0x43
> stack pointer      0x0f
> accumultor         0x00
> flag register      0x80
>
> ---------------------------------------        
> Posted throughhttp://www.EmbeddedRelated.com

look up boot loader
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