8085 Microprocessor T-States Calculation

To determine the number of T-states required to execute an instruction on an 8085 microprocessor, we need to understand the relationship between clock frequency, time period, and T-states.

Clock Frequency and Time Period

The clock frequency is the rate at which the microprocessor operates. The time period is the duration of one complete clock cycle. They are inversely related.

Given:

• Clock frequency (\(f\)) of 8085 microprocessor = 5 MHz

First, let's convert the frequency to Hertz (Hz):

\( f = 5 \text{ MHz} = 5 \times 10^6 \text{ Hz} \)

The time period (\(T\)) of one clock cycle is given by the formula:

\( T = \frac{1}{f} \)

Substituting the given frequency:

\( T = \frac{1}{5 \times 10^6 \text{ Hz}} = 0.2 \times 10^{-6} \text{ s} \)

We can express this time in microseconds (\(\mu\text{s}\)), since \(1 \times 10^{-6} \text{ s} = 1 \mu\text{s}\):

\( T = 0.2 \mu\text{s} \)

T-States and Instruction Execution

In an 8085 microprocessor, one T-state (or Clock State) corresponds to one clock period. Therefore, the time duration of one T-state is 0.2 \(\mu\text{s}\).

Given:

• Time required to execute an instruction = 1.4 \(\mu\text{s}\)

To find the number of T-states needed for executing the instruction, we divide the total instruction execution time by the time duration of a single T-state:

Number of T-states = \( \frac{\text{Instruction execution time}}{\text{Time per T-state}} \)

Substituting the values:

Number of T-states = \( \frac{1.4 \mu\text{s}}{0.2 \mu\text{s}} \)

Number of T-states = \( 7 \)

Final Calculation Summary

Here's a quick summary of the steps involved in calculating the T-states:

Therefore, 7 T-states are needed for executing the instruction.