Question

Explain the following:

T-States

Answer 1

A T–state is the smallest unit of time in a microprocessor, equal to one clock period of the processor. 

Explanation

• Each operation in a microprocessor is synchronised with the clock signal.
• One clock pulse = one T–state.
• The duration of a T–state depends on clock frequency:

T–state = `1/"Clock Frequency"`

T–states → Machine Cycle → Instruction Cycle

Example (8085)

If clock frequency = 3 MHz

T = `1/(3 xx 10^6)` = 333 ns

If an instruction takes 10 T–states

Execution time = 10 × 333 ns

= 3.33μs