Configuration of unused program memory

[sukrubahadirarslan]

Posted on December 15, 2013 at 13:23

Hello.

I use STM3210C-eval board. I program it with Keil V4.70.0.0 . I want to fill the unused memory area so if program counter corrupt and jumps to unused area , I create an reset.How do ı fill unused area with reset vector ?

[chen]

Posted on December 16, 2013 at 11:44

It does not work like that.

If the program resides in internal Flash - unprogramed Flash defaults to 0xff. If your program ever jumps to an area of un-programmed Flash, all the 0xff will result in invalid op-codes (invalid machine code). This in turn will generate an IRQ (which one I forget). So all you have to do is to make the ISRs (the ones you are not coding yourself to so something) do a reset. FYI - most debuggers and programmers (like ST Link Util) will allow you to fill memory (RAM or Flash) BUT do not do it unless you know what you are doing!

[frankmeyer9]

Posted on December 16, 2013 at 12:01

If your program ever jumps to an area of un-programmed Flash, all the 0xff

will result in invalid op-codes (invalid machine code). This in turn will generate an IRQ (which one I forget). BTW, the Microchip PIC12/16/18 have this ''feature'' the OP is asking for. This MCUs interpret 0xFF as instruction code ''NOP'', so busy-ignoring unprogrammed Flash and unimplemented memory in his small 64k adress range. I don't view this as an advantage, rather a method to hide bad programming style and subtle bugs ...

[Tesla DeLorean]

Posted on December 16, 2013 at 12:56

I haven't done it recently, but Keil used to be able to use the scatter file to fill memory regions.

http://www.keil.com/support/docs/3407.htm