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8086 Microprocessor Pin Diagram with Explanation | New Topic
In this note, we are going to know about the 8086 Microprocessor pin diagram with explanation. We are explaining the function of each pin of this microprocessor. Welcome to Poly Notes Hub, a leading destination for polytechnic or diploma engineering notes for polytechnic students.
The 8086 microprocessor is a 16-bit microprocessor invented by Intel in 1978. It has a 20-bit address bus and can access 1 MB of memory. It works in minimum and maximum modes, provides pipelining via a 6-byte instruction queue, and serves as the foundation for the x86 processor family found in most current computers.
Key Features of 8086 Microprocessor
16-bit ALU (Arithmetic Logic Unit)
20-bit Address Bus
16-bit Data Bus
Segmented Memory Architecture
6-byte Prefetch Queue (Pipelining)
Two Operating Modes
40 Pins Total
Here is the pin diagram of the 8086 microprocessor with the function of each pin –
1. Address/Data Bus
Pin(s)
Name
Description
AD0–AD15
Address/Data Bus
These are multiplexed lines. During the first part of the bus cycle, they carry the address, and during the second part, they carry data.
A16–A19/S3–S6
Address/Status Bus
These are multiplexed lines used to provide the upper 4 bits of the 20-bit address or status signals depending on the cycle.
2. Control and Status Signals
Pin
Name
Description
M/IO
Memory/Input Output
Tells whether the current operation is memory access (1) or I/O operation (0).
RD
Read
Signals that the microprocessor is performing a read operation.
WR
Write
Signals that the microprocessor is performing a write operation.
DT/R
Data Transmit/Receive
Used to control the direction of data flow through transceivers.
DEN
Data Enable
Enables the transceivers (data buffers).
ALE
Address Latch Enable
Indicates that valid address is available on the multiplexed bus. It helps to latch the address.
INTA
Interrupt Acknowledge
Indicates the processor has acknowledged an interrupt request.
TEST
Test
Used to synchronize with external WAIT signals during debugging.
3. Interrupt and DMA (Direct Memory Access) Pins
Pin
Name
Description
INTR
Interrupt Request
General-purpose interrupt line. Activated by an external device.
NMI
Non-Maskable Interrupt
Cannot be disabled by software; used for emergency or high-priority interrupts.
HOLD
Hold
Indicates that another device is requesting the use of the address/data bus.
HLDA
Hold Acknowledge
Indicates that the processor has granted the bus control to another device.
4. Clock and Power Pins
Pin
Name
Description
CLK
Clock
Provides timing for synchronization of internal operations.
RESET
Reset
Initializes the microprocessor and starts execution from memory location FFFF0H.
VCC
Power Supply
+5V DC power supply.
GND
Ground
0V reference for the power supply.
5. Ready and Queue Status
Pin
Name
Description
READY
Ready
Used to insert wait states for slow memory or I/O devices.
QS0, QS1
Queue Status
Indicate the status of the instruction queue (used in pipelining).
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8086 Microprocessor Pin Diagram with Explanation | New Topic - Poly Notes Hub
We use cookies to ensure that we give you the best experience on our website. If you continue to use this site we will assume that you are happy with it.
8086 Microprocessor Pin Diagram with Explanation | New Topic - Poly Notes Hub
We use cookies to ensure that we give you the best experience on our website. If you continue to use this site we will assume that you are happy with it.
We use cookies to ensure that we give you the best experience on our website. If you continue to use this site we will assume that you are happy with it.
