1. 1 Q.1) Draw & Explain the Pin-Diagram of Microprocessor in Detail? Ans: The Microprocessor is an 8-Bit general-purpose. is a 40 pin IC, The signals from the pins can be grouped as follows Power supply and clock signals,Address bus,Data bus Pin Diagram and Pin description of It is used to know the type of current operation of the microprocessor. Microprocessor – All concepts, programming, interfacing and applications explained.

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This pin resets the program counter to 0 and resets interrupt enable and HLDA flip-flops. It cannot be enabled or disabled using a program. This signal is used to reset other devices in system. This is a non-maskable interrupt and has highest priority. This is provided by CLK pin. This is an active high, serial output port pin, used to transfer serial 1 microprocezsor data under software control.

It has the lowest priority among the interrupts. The CPU is held in reset condition until this pin is high. These are nothing but the restart interrupts.

This signal is primarily used to synchronize slower peripherals with the microprocessor. Pins like Vcc and ground are classified under this type.

Pin Diagram and Pin description of

Signals associated with the lower order address bus and time multiplexed higher order address bus comes under this type of signals. When the reset pin is activated by microprocwssor external key all the internal operations are suspended and the program counter is cleared and the program execution begins at zero memory address. This distinguishes whether the address is for memory or IO. These pins are used for least significant bits of address bus in the first machine clock cycle and used as data bus for second and third clock cycle.


Whenever the microprocessor receives interrupt signal. Suppose if analog to digital converter is using the address and data bus and if LCD requests the use of address and data bus by giving HOLD signal, digaram the microprocessor transfers the control to the LCD as soon as the current cycle is over. Among the interrupts of microprocessor, TRAP is the only non-maskable interrupt. Signals associated with data bus comes under this type.

Microprocessor Pin Diagram Explained

Introduction In the previous articles we saw about the architecture of microprocessor. This pin provides microprocezsor input data. The serial data on this pin delivers its output to the seventh bit of the accumulator when SIM instruction is executed. Such signals come under this category. It has to be acknowledged.

This is used to acknowledge interrupt. INTR is an interrupt request signal.

A clock cycle is nothing but the time taken between two adjacent pulses of the oscillator. So the first clock cycle means the first transition of pulse from 0volts to 5 volts and then back to 0 volts. This signal is used to control READ operation of the microprocessor.


In the previous article we saw how ALE helps in demultiplexing the lower order address and data bus. This pin provides the serial output data. The serial data on this pin is loaded into micrlprocessor seventh bit of the disgram when RIM instruction is executed.

They insert an internal restart function automatically. That is, they can be enabled or disabled using programs. When it is high. This is a Read control signal active low.

Pin Diagram and Pin description of 8085 Microprocessor

These pins are multiplexed to be used as address bus as well as data bus. That is, an operation is performed when the explantaion goes low. A crystal or RC, LC network is connected to these two pins. While the pin goes low, the address is assigned for the memory.

Classification of Signals The various signals in a microprocessor can be classified as Power supply and Frequency signals: This is an active high output signal used to indicate that the microprocessor is reset.

In simple words clock cycle refers to the transition between o volts to 5 volts and back to explanatio volts.