Question

If CS = A15 A14 A13 is used as chip select logic of a 4 K RAM in 8085 system, its memory range is

Answer 1

Answer:

memory size is 4k to 64k

2^12 =4k

and

2^16 =64k memory

Answer 2

6000 H - 6 FFF H and 7000 H - 7 FFF H

=>To enable the chip cs that is equal to  011 or A15, A14, A13 :-

• 4k means 2^2 * 2^10 =2^12 = 12 bits

        Therefore, 12 address lines are used here that starts from A0 to A11

• For A12 it be can be 1 or 0 and,

        we know A0 to A11 will be either all 0 or all 1 that is:

        0110 (A12) 0000,0000,0000 -6000H

   or, 0110(a12)1111,1111,1111-6FFFH.

• Similarly, when A12 is 1 we get 7000H to 7FFFH.
• So, the memory range become: A0 -  A11 : 6000H - 6FFFH and

                                                              A12 : 7000H - 7FFFH.