A microprocessor is a type of integrated circuit or chip and is the heart of every computer. Ever since the 1980s, advertisements for personal computers have made a big deal about the microprocessors inside the box, even though every computer relies on dozens of other integrated circuits to work properly. But when it was first invented, engineers thought that the microprocessor would be an entire computer on a chip.

1. Microprocessor 80286
Ismile Hossain
1403EEE00052
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2. What is Microprocessor?
Intel 80286 Microprocessor
Comparison of 80286 among some other
Microprocessor
80286 Pin Diagram
Salient Features of 80286
Register Organization of 80286
Register Set of 80286
Flag Registers of 80286
Internal Block Diagram of 80286
Functional Parts
Conclusion
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3. The Microprocessor is a multipurpose
programmable device that accepts digital signal
data as input, processes it according to
instructions, stored in its memory and provide
results as output.
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4. • Introduced in 1982.
• Faster clock speed than previous versions (12.5
MHz, 10 MHz).
• 16-bit Microprocessor.
• Advanced memory management.
• Specially designed for Multiuser & Multitasking
systems.
• 4-level memory protection & support for virtual
memory & operating system.
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5. Microproce
ssor
CPU Speed Data bus Address bus Memory
8086 5 to 10 MHz 16 20 1M
80186 6 to 25 MHz 16 20 1M
80286 6 to 25 MHz 16 24 16M
80486 16 to 100
MHz
32 32 4G
Pentium 4 1.3 to 3.8 GHz 64 40 1T
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7. Two mode of operation.
More Addressable Memory.
Virtual Memory in Protected Mode.
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8. It has 2 operating modes
oReal Address Mode
oProtected Virtual Memory Address Mode
 In Real Address mode the processor can address upto 1MB of
Physical Memory.
 Virtual Address mode is for multiuser/multitasking system. In this
mode of operation the memory management unit can manage upto
1GB of virtual memory.
 In Virtual Address mode one user cannot interface with the other.
Also user cannot interface with operating system. These features are
called protection.
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9.  In protected mode 80286 can address 16
megabytes of physical memory.
 Where 8086 can address 1 megabyte.
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10.  80286 can treat external storage as it were
physical memory.
 Execute programs that are too large to be
contained in physical memory,
 Program can be upto bytes.
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11. The 80286 CPU contains almost the same set of
registers as in 8086.
1. Eight 16-bit general purpose registers.
2. Four 16-bit segment registers.
3. Status & Control register.
4. Instruction Pointer.
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16. Address Unit (AU)
 The address unit is responsible for calculating the physical
address of instructions & data that CPU wants to access.
 This physical address computed by the address unit is
handed over to the Bus Unit of the CPU.
Bus Unit (BU)
 The address latches and drivers in the bus unit transmit
the physical address thus formed over the address bus A0-
A23.
 One of the major function of the bus unit is to fetch
instruction bytes from the memory
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17. Instruction Unit (IU)
 The Instruction Unit accepts instructions from the prefetch
queue & an instruction decoder decodes them one by one.
Execution Unit (EU)
 The output of the decoding circuit drives a control circuit in the
Execution Unit is responsible for instructions received from the
decoded instruction queue, which sends the data part of the
instruction over the data bus.
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18. 80286 took vital role for today’s high end
desktop pc’s. Now we have many high end
processors for desktop, notebook, laptop, mobile
phone etc.
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