8085 Microprocessor (Part I)

Fig: Architecture of 8085 Microprocessor

Internal Architecture of 8085

The internal architecture of 8-bit microprocessor 8085 is divided into the following groups

  • Arithmetic & Logical Group
  • Register Group
  • Interrupt Control Group
  • Serial I/O Group
  • Instruction Register, Decoder, Timing, and Control Group

Arithmetic & Logical Group

Perform arithmetic & logical operations

Consists of

  • Accumulator
  • Temporary Registers
  • Status and Flag Register, and
  • ALU

Register Group

Store data and address in this register group

Consists of 3 types of registers

  • Temporary Registers
  • General Purpose Registers
  • Special Purpose Registers

Special Purpose Registers

  • Program Counter (PC)
  • Stack Pointer (SP)
  • Increment/Decrement Register

Interrupt Control

Accepts different interrupt request inputs such as

  • TRAP
  • RST 7.5
  • RST 6.5
  • RST 5.5
  • INTR

When a valid interrupt request is present, it informs control logic to take action in response to each signal.

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