ARM Microcontroller

There is little doubt that it has a microprocessor inside it.

It can be both. Small one with internal memory is MCU, big one which uses external memory is MPU.

I am not surprised you are confused when you write everything in "lower case" letters!

Do you have so little time that you abandon clarity - by leaving out capitals, punctuation or letters to save a second - when you expect us to spend minutes giving a clear answer? Could you not manage "I am" instead of "i m"? Am I correct to guess that "lg optimus" means something called "Optimus", made by a company which calls itself "LG"?

ARM stands, I believe for "Acorn Research Machines", which is why it is written ARM and not "arm".

I believe a microcontroller is a "computer, with memory, on a chip" which has some pins which can be "on or off" outputs or inputs to drive lamps or receive switched inputs etcetera, so that it can control hardware directly.

A microprocessor can only read or write to external memory, it needs external circuits (pretending to be memory) to [for example] read keyboards or drive printers.

These two micro~ words have become confused because the circuitry that can be put into one chip has become huge. What was originally [years ago] a complete ARM microprocessor and separate memory and input/output circuits can now be put into one chip - making it a microcontroller, which may be described as having an ARM "core". And years ago, before integrated circuits, "core" would have meant memory [magnetic core type] to computer users.

Thanks for your reply. I have one more doubt. Now a days , the modern phones with OS should be treated as embedded system or not. As phones are not made for single purpose. We can do net surfing,play videos,songs and many other.

And is it possible to compile the code in phones like HTC , LG Optimus 2X , because they have large memory. If not than why ?

I note, referring to Wikipedia, as below :-

http://en.wikipedia.org/wiki/IPhone

- that Iphone has 425,000 Applications available. An Application is one word to describe a programme which can be loaded into memory and run.

So I would expect an ARM compiler is feasible for a pocket phone, but maybe there is not any demand for it.

Why struggle with an inadequate thumb-destroying keyboard and a tiny display for a professional application when qualified compilers are available for full sized computers?