I am trying to interface Flash AT29C512 with AT89C51 How do read and write serially between the 8 bit 8051 and 24 bit Flash,
Kindly help if some one has worked on this.
"Why should we not write to ACC directly in 'C'?"
You should not do it in any high-level language!
Because, when you use a high-level language (eg, 'C'), you delegate control of the low-level CPU registers to the compiler.
See: http://www.keil.com/forum/docs/thread8360.asp