About Pin Diagram of 8085 Microprocessor – Pin Details | New Topic [2024]

In this note, we are going to learn about the Pin Diagram of 8085 Microprocessor or about its pin details or configurations. Welcome to Poly Notes Hub, a leading destination for Engineering Notes syllabus wise.

Author Name: Arun Paul.

What is 8085 Microprocessor?

Intel Corporation created the integrated circuit (IC) chip known as the 8085 processor. It is an 8-bit microprocessor, which means that the data it processes is divided into 8-bit segments. It was first introduced in 1976 and saw extensive use in a variety of electronic devices in the late 1970s and early 1980s, including industrial controllers, embedded systems, and personal computers.

📌 Some Important Key Features of this microprocessor:

Pin Diagram of 8085 Microprocessor

Below we show the 8085 Microprocessor Pin Diagram or 8085 Microprocessor Pin Details –

Here’s a quick overview of the pin configuration of 8085 microprocessor –

1. VCC (+5V): This pin provides the supply voltage to the microprocessor. It requires a regulated +5V DC power supply for proper operation. It is basically the power supply pin of the pin diagram of 8085.
2. GND (Ground): Connected to the ground, this pin serves as the reference voltage for the microprocessor’s operation.
3. INTR (Interrupt Request): External devices can use this pin to send interrupt requests to the microprocessor.
4. RST 7.5 (Restart 7.5): This is one of the restart pins used to reset the microprocessor. It is a non-maskable interrupt and has the highest priority.
5. RST 6.5 (Restart 6.5): Another restart pin with lower priority than RST 7.5.
6. RST 5.5 (Restart 5.5): The third restart pin with even lower priority.
7. TRAP: This is the trap interrupt pin, which is used for non-maskable interrupt requests.
8. RST 5.5: The fourth restart pin with even lower priority.
9. SID (Serial Input Data): Used for serial data input to the microprocessor.
10. SOD (Serial Output Data): Used for serial data output from the microprocessor.
11. IO/M (Input/Output and Machine Cycle): This pin distinguishes between memory and I/O operations during machine cycles.
12. HLDA (Hold Acknowledge): Indicates that the microprocessor has received the HOLD request and is relinquishing control of the buses.
13. ALE (Address Latch Enable): Generates a signal to latch the address from the address bus during the first clock cycle of a machine cycle.
14. AD0-AD7 (Address/Data Bus): These lines carry both address and data information during various machine cycles.
15. A15-A8 (Higher Order Address Bus): These lines carry the higher-order address bits during memory and I/O operations.
16. S1 and S0 (Status): These pins indicate the status of the microprocessor during various operations.
17. WR (Write): This signal indicates a write operation from the microprocessor to an external device.
18. RD (Read): This signal indicates a read operation from an external device to the microprocessor.
19. READY: Indicates that the external device is ready to communicate with the microprocessor.
20. ALE (Address Latch Enable): Same as pin 13.
21. INTA (Interrupt Acknowledge): This signal indicates that the microprocessor has acknowledged an interrupt request.
22. RESET IN: This is the external reset input used to reset the microprocessor.
23. X1 and X2 (Crystal Oscillator Pins): These pins are connected to an external crystal oscillator that provides the clock signal for the microprocessor.
24. CLK (Clock): Provides the system clock input to the microprocessor.
25. RESET OUT: This is the reset output signal generated by the microprocessor to reset external devices.
26. Hold: This pin is used to pause the microprocessor’s operation temporarily.

In the above pin diagram of 8085 microprocessor, we describe every pin of the 8085 Microprocessor.