Digital Electronics - Microprocessor Fundamentals - Discussion

Control bus just used to pass the control to the processor or to the devices connected (i.e.) in read operation control is given to devices to write on the address, whereas on the write operation the processor is given control to write on the memory. Thus is the work of control bus,

But whereas address decoder only correctly decodes the address and identifies which is needed to be operated and sends the signal to the control bus.

An address decoder is only circuit that decides which IC is to be activated using CS bar signal.

why means it have 2 Ic but ate address location based the decoder of the o\p can be appears.

Ex:
Let us take,
Ic1

Ic2

Ic1 adds location -2001 to 2090.
Ic2 adds location-4000 to 8500.

The selection of address is 3500 so it goes the address location of Ic2 so Ic2 can indicates the o/p.

Decoder gives output to only one line so at a time only one device is actived.

Decoder is atype of logic device that uses different control signal along with buses to give a suitable logic that enable or disable i/o, memory what ever required.