The 8051 Microcontroller and Embedded

Department of Computer Scien

ce and Information Engineering

National Cheng Kung University, TAIWAN

HANEL

INSIDE THE COMPUTERInternal Working of Computers(cont’)

Ex. (cont’)4.
¾
From memory location 1402H it fetches code 04H
¾
After decoding, the CPU knows that it must add to the contents of register A the byte sitting at the next address (1403)
¾
After the CPU brings the va

lue (42H), it provides

the contents of register A

along with this value to

the ALU to perform the additionƒ

It then takes the result of the addition from the ALU’s output and puts it in register A

ƒ

The program counter becomes 1404, the address of the next instruction

...