8085

The 8085 Processor Designed in 1976. 6500 transistors used in 8085 processor.   

Features

• It is an 8 bit microprocessor.
• It is a single chip NMOS device implemented with 6200 transistors.
• Cock frequency is 3 MHz
• It requires +5V power supply.
• It has 16-bit address bus and hence can address up to 216 = 65536 bytes (64KB) memory locations through A0-A15
• The first 8 lines of address bus and 8 lines of data bus are multiplexed AD0 – AD7
• Data bus is a group of 8 lines D0 – D7
• It supports external interrupt request. .
• A 16 bit program counters (PC)
• A 16 bit stack pointer (SP)
• Six 8-bit general purpose register arranged in pairs: BC, DE, HL.
• It requires a signal +5V power supply and operates at 3.2 MHZ single phase clock.
• It is enclosed with 40 pins DIP (Dual in line package).
• It provides 74 instructions with five addressing modes.
• It provides 5 hardware interrupt and 8 software interrupts.

Ø  Up to 8 MHz

Ø  64 KB RAM

Ø  Single voltage

Ø  On-chip peripherals

Ø  256 I/O ports

Ø  8080 object-code compatible

Ø  40-pin DIP

Ø  44-pin PLCC

Architecture Of 8085

1. ALU
2. Timing and Control Unit
3. General Purpose Registers
4.  Program Status word
5.  Program Counter
6. Stack Pointer
7. Instruction Registers and Decoder
8. Interrupt Control
9. Serial I/O Control
10.  Address Bus
11. Data Bus

The 8085 Bus Structure

The 8-bit 8085 CPU communicates the other units using 16-bit address bus, an 8-bit data bus and a Control bus.

Over all Structure