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Microcontroller vs microprocessor; 8051 features

Short answer

A microprocessor is a CPU-only chip requiring external memory and I/O; a microcontroller integrates CPU, RAM, ROM, I/O, timers, and serial port on one chip. The 8051 features an 8-bit CPU, 4 KB ROM, 128 B RAM, 32 I/O lines, two 16-bit timers, UART, five interrupt sources with two priority levels, bit-addressable RAM, and on-chip oscillator.

How are microcontrollers different from microprocessors? Write the features of 8051 microcontroller.

A microprocessor is a CPU on a chip that needs external memory and I/O chips. A microcontroller puts the CPU, RAM, ROM, I/O ports, timers and serial port on a single chip, forming a complete small computer.

Difference

PointMicroprocessorMicrocontroller
ContentsCPU onlyCPU + RAM + ROM + I/O + timers + UART
External partsMemory, I/O chips neededFew or none
Cost, size, powerHigherLower
Instruction setMany, for general processingFew; bit-oriented I/O control
Clock speedHigh (GHz)Low (MHz)
UsePCs, servers, general computingEmbedded systems: washing machine, remote, car modules
Example8085, 8086, Pentium8051, PIC, AVR

Features of the 8051

  • 8-bit CPU with 8-bit data bus and 16-bit address bus (64 KB code, 64 KB data).
  • 4 KB on-chip ROM and 128 bytes on-chip RAM.
  • 32 I/O lines in four 8-bit ports (P0-P3).
  • Two 16-bit timers/counters (Timer 0 and 1).
  • Full-duplex serial port (UART).
  • 5 interrupt sources with two priority levels.
  • Bit-addressable RAM and SFRs (Boolean processor); special function registers.
  • On-chip clock oscillator (11.0592 or 12 MHz crystal); 40-pin DIP.

✓ Answer checked by Claude Opus 5.5 (high effort)

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