Explain Multiplexed Address and Data Bus of 8085 MPU.
Explain functions of the following pins of 8085 Microprocessor : Multiplexed address/data bus pin (ADO - AD7)
(1) Microprocess 8085 has 8-bit data bus and 16-bit address bus.
(2) The least significant 8-bits of address bus are passed on the same eight lines as that of data bus i.e. on the signal lines AD7 – AD0.
(3) These signal lines are bi-directional.
(4) They are used for dual purpose for lower order 8-bit of address and as well as 8-bit of data. This is known as multiplexing and such bus is known as multiplexed bus.
(5) In multiplexed means, first to select one and then other.
(6) In executing an instruction, during earlier part of cycle these lines are used as the lower order address bus. During label part of cycle, these lines are used as data bus.