Somehow reading the chapter on "CPU registers of the 8051 variants"user guide 02.2001 about Macro Assembler and Utilities on registers R0-R7 give me the impression that the 8051 has a on-chip R0-R7 that in the chip but not in DATA area 0x00 - 0x1F. However, using register bank 0 and much debugging, realised it is not. The R0-R7 resides on the DATA area 0x00-0x1F. Is it just me or the documentary on that is confusing?
You're trying to learn very basic things about 8051s from not exactly the right document. The A51 manual is no substitute for a proper textbook on the '51 architecture. Get "the bible" (search this forum and you'll find ample links to it), or a real textbook, and learn processor behaviour from that. Then come back to the A51 manual to learn how those hardware concepts are represented in software.
Get "the bible" (search this forum and you'll find ample links to it), or a real textbook, and learn processor behaviour from that. Then come back to the A51 manual to learn how those hardware concepts are represented in software. "the bible" and this is what I recommend for starting with the '51 http://www.8052.com/tut8051.phtml here are the links to "the bible" Chapter 1 http://www.semiconductors.philips.com/acrobat/various/80C51_FAM_ARCH_1.pdf chapter 2 http://www.semiconductors.philips.com/acrobat/various/80C51_FAM_PROG_GUIDE_1.pdf chapter 3 http://www.semiconductors.philips.com/acrobat/various/80C51_FAM_HARDWARE_1.pdf Erik
yes, these 8051 bibles make it very clear. thanks!