signal diagram of 8085


Signal diagram of 8085

all signal are classified into six groups:-

address bus
  1. data bus
  2. control and status signal 
  3. power supply and frequency signals
  4. External initiated
  5. Serial input-output signals

full description of groups

address and data buses:-

       1.   address buses are of 16 bits  A0-A15 which are divide into two-part
                lower order address bus A0-A7 and higher-order address buses A8-A15.
       2. address bus has unidirectional.
        3. data bus are 5-bits (D0-D7).
        4. multiplexed address and data buses are AD0-AD7.

 control and status signal:-

      the control signal is control  ALE, RDbar, WRbar, IO\Mbar, status signal.


               it is used to enable address latch.

               it indicates whether bus functions data bus or address bus.

               if ALE=1 then the bus function as the address bus.  

               if ALE=0then bus function data bus.

  status signals:-

            S1              S0             operations

                 0                   0                                    hold
                 0                   1                                    write
                 1                   0                                    read  

             1               1                               fetch

Externally initiated or interrupt signals:-

externally initiated or interrupt signals

externally initiated or interrupt signals



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