Can we use objective C for LPC21xx series micro controller.
"no. we found the LPC21XX only supports C and C++ subset."
So you found wrong. And hence gave an incorrect answer.
The LPC21xx only supports machine code instructions. The real question is if any tool that supports Objective C can (directly or indirectly) produce machine code instructions for a LPC21xx.
Any experience you may have with the Keil compilers is irrelevant for discussing capabilities of other compilers.
I got the answer, thanks.