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Microprocessor - 8086 Pin Configuration

8086 was the first 16-bit microprocessor available in 40-pin DIP (Dual Inline Package) chip. Let us now discuss in detail the pin configuration of a 8086 Microprocessor.

8086 Pin Diagram

Here is the pin diagram of 8086 microprocessor −

 

• The description of the pins of 8086 is as follows:
• AD0-AD15 (Address Data Bus): Bidirectional address/data lines. These are low order address bus. They are multiplexed with data.

When these lines are used to transmit memory address, the symbol A is used instead of AD, for example, A0- A15.

• A16 - A19 (Output): High order address lines. These are multiplexed with status signals.
• A16/S3, A17/S4: A16 and A17 are multiplexed with segment identifier signals S3 and S4.
• A18/S5: A18 is multiplexed with interrupt status S5.
• A19/S6: A19 is multiplexed with status signal S6.
• BHE/S7 (Output): Bus High Enable/Status. During T1, it is low. It enables the data onto the most significant half of data bus, D8-D15. 8-bit device connected to upper half of the data bus use BHE signal. It is multiplexed with status signal S7. S7 signal is available during T3 and T4.
• RD (Read): For read operation. It is an output signal. It is active when LOW.
• Ready (Input): The addressed memory or I/O sends acknowledgment through this pin. When HIGH, it denotes that the peripheral is ready to transfer data.
• RESET (Input): System reset. The signal is active HIGH.
• CLK (input): Clock 5, 8 or 10 MHz.
• INTR: Interrupt Request.
• NMI (Input): Non-maskable interrupt request.
• TEST (Input): Wait for test control. When LOW the microprocessor continues execution otherwise waits.
• VCC: Power supply +5V dc.
• GND: Ground.