What's the differece between DATA(BIT,IDATA,...) and DS ?
Have you tried looking up each term in the assembler Manual, and comparing their descriptions?
http://www.keil.com/support/man/docs/a51/a51_st_ds.htm
http://www.keil.com/support/man/docs/a51/a51_st_data.htm
etc...
But,when do i use them,i just can't understand yet?!
here are the links to "the bible" Chapter 1 - 80C51 Family Architecture: 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
The so-called "bible" doesn't tell you how to write programs in assembler, nor how to use any particular assembler.
Unfortunately for the OP (and others like him), everything on the Keil site seems to be focussed on 'C' - there is precious little on how to write programs in assembler...
Maybe check-out the Book list:
http://www.keil.com/books/8051books.asp
The so-called "bible" doesn't tell you how to write programs in assembler, nor how to use any particular assembler. correct, but it does give an insight as to What's the differece between DATA(BIT,IDATA,...)
Erik
Yes: familiarity with the so-called "bible" is necessary, but not sufficient!