1. Unit-III
8051 Microcontroller
Functional block diagram and pin diagram of 8051,
Power supply, clock and reset circuit,
Program Counter and ROM space in 8051,
Program and Data Memory organization,
addressing modes. Instruction Set of 8051: data
transfer, arithmetic and logical, program branching
instructions, single bit manipulation, shift and
Boolean variable manipulation, Interrupt of 8051.
4. Types of addressing modes:
• Direct addressing mode: The address field points
directly to the memory location where data is stored
• Indirect addressing mode: The address field points to
a register and then to the intended memory location
• Register addressing mode: The source and
destination are registers
• Immediate addressing mode: The programmer can
directly specify a constant or immediate value
5. Instruction Set Examples
• ADD – Combines two numbers.
• COMPARE – Compare and contrast numbers.
• IN – The input of data from a device, such as a keyboard.
• JUMP – Go to a certain RAM address.
• JUMP IF – A conditional statement that jumps to a
specific RAM location.
• LOAD – This command transfers data from RAM to the
CPU.
6. A 'Logical Instruction' in Computer Science
refers to operations that perform bitwise
logical operations on source registers, such as
AND, OR, exclusive OR, and bit clear. These
instructions manipulate binary values to
perform logical operations like clearing status
bits or changing interrupt masks
