As in one of the replies i got from this discussion forum on my clock codes some one pointed out that:-

"Do not use r0 and r1 for clock registers. Use stratch pad area (30h to 7fh). r0 r1 are valuable registers (see indirect addresing. And dont say i don't want to use interrupts , indirect addressing , .....)"

I have seen indirect addressing but did not understand.?

what is scratch pad registers and when to use them.