A microprocessor consists of a central processing unit and minimal additional components like registers, while a microcontroller includes more integrated components like memory, input/output pins and communication modules. Specifically, a microcontroller combines a microprocessor with RAM, ROM, timers and other peripherals onto a single chip, making it self-contained and suitable for embedded applications where cost, power and space are priorities. In contrast, a microprocessor's components are separate, providing more flexibility but also greater expense.

1. Microcontroller Vs Microprocessor
A microprocessor simply consists of the processor, the ALU
(Arithmetic Logic Unit), the Instruction Decoder and a few registers
which are used to store data for mathematical and logical operations.
E.g – 8085, 8086
A microcontroller includes a processor, the ALU, Instruction
Decoder, registers, code storage space(flash memory/ROM), RAM,
general purpose I/O pins, timers, interrupt controller, serial
communication module etc.
 That is, the microcontroller is a microprocessor with some basic
modules.

2. Components of a
microprocessor/controller
• CPU: Central Processing Unit
• I/O: Input /Output
• Bus: Address bus & Data bus
• Memory: RAM & ROM
• Timer
• Interrupt
• Serial Port
• Parallel Port
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3. General-purpose microprocessor:
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• CPU for Computers
• Commonly no RAM, ROM, I/O on CPU chip itself
CPU
General-
Purpose
Micro-
processor
RAM ROM I/O
Port
Timer
Serial
COM
Port
Data Bus
Address Bus
Many chips on motherboard

4. 8051, Atmega8, PIC 18F4550

5. • A single-chip computer
• On-chip RAM, ROM, I/O ports...
• Example：Motorola’s 6811, Intel’s 8051, Zilog’s Z8 and PIC 16X
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RAM ROM
I/O
Port
Timer
Serial
COM
Port
Microcontroller
CPU
A single chip
Microcontroller

7. Microprocessor
• CPU is stand-alone, RAM,
ROM, I/O, timer are separate
• designer can decide on the
amount of ROM, RAM and
I/O ports.
• expensive
• versatility
• general-purpose
• High processing power
• High power consumption
• Instruction sets focus on
processing-intensive
operations
• Typically 32/64 – bit
• Typically deep pipeline (5-20
stages)
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Microcontroller
• CPU, RAM, ROM, I/O and timer
are all on a single chip
• fixed amount of on-chip ROM,
RAM, I/O ports
• for applications in which cost,
power and space are critical
• single-purpose (control-oriented)
• Low processing power
• Low power consumption
• Bit-level operations
• Instruction sets focus on control
and bit-level operations
• Typically 8/16 bit
• Typically single-cycle/two-stage
pipeline
Microprocessor vs. Microcontroller

8. Some Popular Microcontrollers…
• 8051
• Microchip Technology PIC
• Atmel AVR
• Texas Instruments MSP430 (16-bit)
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