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:
| Features | Description |
|---|---|
| 8-bit Architecture | The 8085 is an 8-bit microprocessor, hence it processes data in 8-bit segments. |
| Instruction Set | It features a relatively simple instruction set of approximately 74 instructions. These instructions carry out basic arithmetic, logic, and data transfer tasks. |
| Clock Speed | The 8085 commonly ran at clock speeds of 2 to 3 MHz. Later versions and clones could achieve faster speeds. |
| Addressing Modes | Accessing memory and I/O devices is made flexible by the 8085’s support for multiple addressing modes, including register, indirect, and direct addressing. |
| Memory | Up to 64 KB of memory can be directly addressed by the 8085, while systems with less memory were frequently the result of peripheral and practical restrictions. |
| Peripheral Interface | It has integrated I/O support, which enables communication with peripherals like keyboards, monitors, and storage units. |
| Interrupts | Because the 8085 supports interrupts, external devices can handle urgent tasks by interrupting the microprocessor’s regular execution flow. Different types of interrupts in 8085: TRAP, RST (5.5, 6.5, 7.5), INTA, INTR, SID, and SOD. |
| Data and Address Buses | It features an 8-bit data bus and a 16-bit address bus, therefore it can address up to 64 KB of memory. |
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 –
- 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.
- GND (Ground): Connected to the ground, this pin serves as the reference voltage for the microprocessor’s operation.
- INTR (Interrupt Request): External devices can use this pin to send interrupt requests to the microprocessor.
- 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.
- RST 6.5 (Restart 6.5): Another restart pin with lower priority than RST 7.5.
- RST 5.5 (Restart 5.5): The third restart pin with even lower priority.
- TRAP: This is the trap interrupt pin, which is used for non-maskable interrupt requests.
- RST 5.5: The fourth restart pin with even lower priority.
- SID (Serial Input Data): Used for serial data input to the microprocessor.
- SOD (Serial Output Data): Used for serial data output from the microprocessor.
- IO/M (Input/Output and Machine Cycle): This pin distinguishes between memory and I/O operations during machine cycles.
- HLDA (Hold Acknowledge): Indicates that the microprocessor has received the HOLD request and is relinquishing control of the buses.
- ALE (Address Latch Enable): Generates a signal to latch the address from the address bus during the first clock cycle of a machine cycle.
- AD0-AD7 (Address/Data Bus): These lines carry both address and data information during various machine cycles.
- A15-A8 (Higher Order Address Bus): These lines carry the higher-order address bits during memory and I/O operations.
- S1 and S0 (Status): These pins indicate the status of the microprocessor during various operations.
- WR (Write): This signal indicates a write operation from the microprocessor to an external device.
- RD (Read): This signal indicates a read operation from an external device to the microprocessor.
- READY: Indicates that the external device is ready to communicate with the microprocessor.
- ALE (Address Latch Enable): Same as pin 13.
- INTA (Interrupt Acknowledge): This signal indicates that the microprocessor has acknowledged an interrupt request.
- RESET IN: This is the external reset input used to reset the microprocessor.
- X1 and X2 (Crystal Oscillator Pins): These pins are connected to an external crystal oscillator that provides the clock signal for the microprocessor.
- CLK (Clock): Provides the system clock input to the microprocessor.
- RESET OUT: This is the reset output signal generated by the microprocessor to reset external devices.
- 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.
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