I have said it before on this forum and I will say it again now. No one should be allowed to write C code for a microcontroller until they have mastered working in assembler language on that same processor architecture.

Waqar, in all due respect, I do not think you are even close to being ready to program in C on an 8051. You have certainly not demonstrated in this community that you understand the 8051 assembly code to the level to be considered proficient. It is true, C code isolates you from the tedium of how to put sequences of instructions together to form program logic. However with C it is even MORE important to understand how all aspects of the processor work from i/O modes of port pins, interrupts, stacking operations, memory maps, to nuiances of how timers, uarts, and external busses work.

Michael Karas