code working in simulator but not when burnt.

thanks u all for responding and giving me suggetions ..
ill try to solve my problem by following ur suggestion and will gat back to u if there is any problem.. thanks all of u once again..

That's not strictly true, and thinking that way can get misleading.

The 8052 processor itself knows nothing about Flash, RAM, or any other memory technology.

All the 8052 processor itself knows is that it has a CODE address space, and an XDATA address spaces - and those two address spaces are quite distinct.

The CODE address space is where instructions are fetched from for execution - but it can also be read as data.
The key thing to remember is that the 8052 architecture has no way to write to CODE space - it is strictly read-only.
Thus most applications will, in practice, use some kind of read-only memory technology (such as flash) in the CODE space.

The XDATA address space has both read & write data access - but instructions for execution cannot be fetched from XDATA space.
Thus most applications will, in practice, use some kind of read-write memory technology (such as RAM) in the XDATA space.

Indeed!

It all rather sounds like you're trying to run before properly learning to walk!

I think you should spend some time reviewing the basics of the 8051 architecture, and then some simple, basic programming examples before continuing with this.

Standard advice:

First, you need to read the uVision Getting Started guide, and work through the example projects in it.
This will give you a proper introductions to the tools, how they work, and how to use them - rather than just jumping-in blindly at the deep-end!
You need to study the following documents - commonly referred to as "the bible" for the 8051:

Chapter 1 - 80C51 Family Architecture:
www.nxp.com/.../80C51_FAM_ARCH_1.pdf

Chapter 2 - 80C51 Family Programmer's Guide and Instruction Set:
www.nxp.com/.../80C51_FAM_PROG_GUIDE_1.pdf

Chapter 3 - 80C51 Family Hardware Description:
www.nxp.com/.../80C51_FAM_HARDWARE_1.pdf

Are you also a newbie to 'C' programming in general?
If so, you'll also need a good 'C' textbook.

Here are some other introductory & reference materials:
http://www.keil.com/books/8051books.asp
www.8052.com/tutorial.phtml

You will need to read the Data Sheet for your particular processor, and the Manual(s) for any development boards, etc.

You will need to read the Manuals for the C51 Compiler, A51 Assembler, etc, etc,...

thanks alot neil for those documents and information u have given.. may be ur true that am trying to run....thanks alot once again...

can any one please explain me how to select a microcontroller based on XDATA size CODE size and HEX file size.Is it true that the particular UC should have flash memory of size >= HEX file size??

.Is it true that the particular UC should have flash memory of size >= HEX file size??

the size of the HEX file is no indication of the size of the program at hand. if you want to be sure, you must generate a .bin file using 'fromelf'. such a file such can be programmed directly onto flash, hence: if that one is smaller than the storing media, you are in business! you can also have a look at the map file, of course.

If your program requires x bytes of XDATA space and y bytes of CODE space, it should be obvious that your target system must provide at least x bytes of XDATA and at least y bytes of CODE space.

Those could be provided within the microcontroller itself, or as external memory...

So feed those criteria into this parametric search engine: http://www.keil.com/dd/search_parm.asp

That's true.

For further details, including the hex file format, see: http://www.keil.com/support/docs/3250.htm

"if you want to be sure, you must generate a .bin file"

Not at all - the C51 tools tell you the image size directly!

"using 'fromelf'"

The C51 tools don't use ELF - so I doubt that 'fromelf' will help?

" if that one is smaller than the storing media, you are in business!"

Not quite - you need both the Code storage area and the data storage area to be of adequate size before the program will run correctly...

Andy,
I have a terrible headache today - something made me see "ARM" toolchain instead of C51! I apologize to the OP.

so as said by per before that
The flash memory is for code - the instructions telling the processor what to do.

The data memory (RAM) is for variables, i.e. letting the program keeping track of what it is doing.

can i select a UC with flash memory >= code size?? and please tell me what does data size represent.

The text "The flash memory is for code" should be read as "is intended for code". I also wrote that if "an array stores constant - unchanging - data, then you can move the array into the flash, i.e. among the code."

No, I don't think any manufacturer sells any processor with flash memory > code size. But the compiler does support placing read-only data into the code region, so it will be enough to have a processor with a flash size larger than what you need for the program code. The remaining region of the flash may then be used for constant data.

There are some 8051 chips that have a partially overlapping memory structure, where the application can reprogram the flash. This can allow the flash to be used for semi-static data - but the flash memory supports a limited number of write cycles, so the flash region can't be used instead of RAM.

I'm not sure what you mean with "what does data size represent". The processor may have more than one data region, in which case there may be more than one data size.

Oh yes they do!

The 8051 architecture limits the CODE size to 64K - but there are 8051-based chips available with >64K Flash (eg, SiLabs).

I presume you mean:

"can I select a uC with flash memory >= my progran's code size?"

The answer should be obvious!

Think about it: If you buy a PC program that says it requires x MB RAM and y MB disk, can you use it on a PC that has more RAM and disk than that...?

Depends on view. The 8051 chips with > 64kB flash has the flash mapped for CODE space. It's just that you will need banking or similar.

But have you seen any chip manufacturer selling a 8051 with flash for the RAM area - unless it has the overlapped CODE/XDATA regions I mentioned?

"can I select a uC with flash memory >= my progran's code size?" sorry if iam not clear with this statement here i mean to ask if it is sufficient to consider code size in the selection of UC without considering the XDATA size, as it was said befor that the XDATA has nothing to do with flash memory size and it looks for RAM.so i just wanted to confirm that point.

and in the statement "what does data size represent" i wanted to know what exactly it represents as when i compiled my code in keil i got as Program Size: data=9.0 xdata=6320 code=3632.

in the beginning i thought that i can use 89c51 for my code what ever i had, later on with all of ur advice i understood that i have to add an external RAM as my XDATA is large.later i was suggested to go for UC with larger flash memory as my HEX file size is around 12K. This is the reason i raised an issue of "can I select a uC with flash memory >= my progran's code size?"

Please tell me if that is sufficient and also about the data=9.0