Timing Diagram of the 8088 Microprocessor:

Each bus cycle of the 8088 processor consists of four T states: T₁, T₂, T₃ and T₄. During the first clock cycle T_1, ALE signal is high and A₁₉/S₆-A₁₆/S₃ are used as A₁₉-A₁₆ address buses, AD₇-AD₀ can be used as A₇-A₀ address buses. Hence, the leading edge of ALE is used to latch the valid 20-bit address during T₁ states. After T₁ state A₁₉/S₆-A₁₆/S₃ are used as status signals S₆-S₃, the middle bus A₁₅-A₈ are always active as address buses but AD₇-AD₀ are tristated.During T₃ and T₄ data are read from memory and placed into the data bus. Therefore, AD₇-AD₀ is used as data bus in T₃ and T₄ durations. Figure 5.26 shows the timing diagram of the 8088 Microprocessor for memory read operation of 8088 microprocessor. After T₄ the next bus cycle will be started.

Figure 5.27 shows the timing diagram of the 8088 Microprocessor for memory write bus cycles. In memory cycle, data will be available on the data bus during T₂, T₃ and T₄ and the status signals are valid for T₂, T₃ and T₄ durations. After T₄ address/data bus, AD₇-AD₀ arc tristated.