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An output device is interfaced with 8-bit microprocessor 8085A. The interfacing circuit is shown in figure
The interfacing circuit makes use of 3 Line to 8 Line decoder having 3 enable lines E1 ,E2 ,E3. The address of the device is
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- 50H
- 500H
- A0H
- A000Hs
Correct Option: B
To enable 3L × 8L decoder, three enable lines E1 (which is connected as an output of AND-gate)
should be HIGH and E2 and E3 should be active low, it means I0/m should be active low which is indicating that it is memory mapped I/O interfacing. So address of the device will be in 16-bits. To select output port through decoder 2nd line the status of A15 (I2) A14(I1) A13(I0) = 010 and to enable decoder through E1 enable line A12 = 1 and A11 = 0 and by default as a starting address other address lines (A10......A0) shold be zero. So, overall port address is 
