General 8086 System bus structure and operation with basic system Timing Diagram in 2020 Part 1/2 скачать в хорошем качестве

General 8086 System bus structure and operation with basic system Timing Diagram in 2020 Part 1/2

General 8086 System bus structure and operation with basic system Timing Diagram Part 1/2 in 2020. 8086 has multiplexed address and data bus.Inorder to reduce the number of pins in the processor multiplexing technique used To demultiplex the address and data using the latches and transreceivers with the help of ALE signal. One bus cycle consists of at least 4 clock cycles like T1,T2,T3,T4. During the T1 ALE activates and the processor sends out an address on the address bus.ALE is used to latch the latch and it activates.Parallely the data will be transferred during the T3 & T4.T2 is used for changing the direction of the bus during reading operation. Ready signal is sampled during the T3. In general peripherals are slow devices ,so inorder to synchronize both CPU and peripherals ready signal is used. In case ready is not ready (=0)indication wait state is inserted between the T3 and T4. During the wait state, the signals on the buses remain the same as they were at the start of the wait state. If the ready input is made high during wait state, then after wait state the 8086 will go on with the regular T4 of the machine cycle. Until ready input is made high the wait states are inserted continuously. S0S1S2 are used in maximum mode for identifying the bus transaction by the bus controller. s3 s4 used for indicating which segment register used for this bus cycle for forming the address.s5 interrupt enable bit of the flag register.S6=0 and S7 reserved bit or spare bit