Microprocessors and Microcontrollers

Instruction Set of 80386 Microprocessor: The 80386 processor can support all the instructions of 80286. Usually, the instruction sets of 80286 are designed to operate with 8-bit or 16-bit data, but the same mnemonics may be executed with 8-bit, 16-bit, and 32-bit operands in the 80386 processor. Due to the enhanced architecture of 80386 over […]

Operating Modes of 80386 Microprocessor: The Operating Modes of 80386 Microprocessor are given below: Real addressing mode, Protected mode, and Virtual 386 mode. In this section, the above three modes are explained elaborately. Real addressing mode The 80386 always starts from the memory location FFFFFFF0H in the real address mode whenever the pro­cessor is reset.

Data Types of 80386 Microprocessor: The 80386 processor is able to support the following data types: Bit Bit Field: A group of 4 bytes ( 32 bits) Bit String: A string of contiguous bits of maximum 4 GB in length Signed Byte: Signed byte data Unsigned Byte: Unsigned byte data Integer Word: Signed 16-bit data

Addressing Modes of 80386 Microprocessor: The 80386 can operate in all the addressing modes which were available with the 80286 processor. The 80386 processor can also operate in all addressing modes of 80286 with 32-bit immediate or 32-bit register operands or displacements. Besides all addressing modes of 80286, the 80386 has a family of scaled

Intel 80386 Pin Diagram Description: The 80286 family has a sinking current of 2.0 mA but each output pin of the 80386 is capable of sinking 4.0 mA current for address and data buses or 5.0 mA for other connections. Therefore, there is significant improvement in the current handling capability. Figure 11.36 shows the Intel

Registers of 80386 Microprocessor: The 80386 processor has significantly extended the 8086 register set. All the registers of 80286 are existing in the 80386 processor and some new registers have been added in 80386. Generally, the registers of 80386 microprocessor are of 32 bits and they can be used as 8-bit and 16-bit registers. Figure

Internal Architecture of 80386 Microprocessor: The simplified block diagram of the 80386 processor is depicted in Fig. 11.31 and Fig. 11.32 shows the detailed architecture of 80386. The internal architecture of the 80386 processor consists of three different sections such as Central Processing Unit (CPU ), Memory Management Unit (MMU) and Bus Interface Unit (BIU). Central Processing

Protected Virtual Address Mode (PVAM) in 80286: Protected Virtual Address Mode (PVAM) in 80286 – The 80286 executes a fully upward-compatible superset of the 8086 instruction set in protected virtual address mode. The PVAM operation of the 80286 processor provides memory management and protection mechanisms and associated instructions. The 80286 enters into protected virtual address

Real Addressing Mode of 80286: In the Real Addressing Mode of 80286 operation, 80286 executes a fully upward-compatible instruction of the 8086 instruction set. It works as a fast 8086. In Real Addressing Mode of 80286, the 80286’s object code is compatible with 8086 and 8088 software. In this addressing mode, the 80286 addresses a

80286 Instruction Set: The 80286 Instruction Set are upwardly compatible with that of the 8086 processor. Most of the 80286 Instruction Set are the same as the instructions of 8086. The additional instructions of 80286 processor are as follows: ARPL (Adjust RPL Field of Segment Selector) CLTS (Clear Task Switched Flag in CRO) LAR (