RAM Chip

Question

A RAM chip has 7 address line , 8 data lines and 2 chips select lines. Then the number of memory locations is ...

a. 2^12

b.2^10

c.2^19

d.2^13

Plz describe with a proper diagram and significance of each lines.

Comments

Total 2^12 is it correct?

3 bits for address,  8 bits for data 1 bit for chip!

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Can u please explain more

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Total number of memory locations will be

2*2^6*8 which is equal to 2^10.Because one address line of the address lines will be used to select one of the two chip selects.The remaining 6 address lines will be used to address one of the address location of the chip.And there are 8 data lines so each word of the chip is 8 bits long.

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total memeory location  = 2^12

2(chip select)

7(address selection)

3(data bits selection)

 

Answer 1

Number of data lines (word size) = 8

Number of address lines = 7

Total number of addressable memory locations/number of memory words = $2^{7}$ = 128

The number of data lines just gives the word size. 

Thus, the answer should be $2^{7}$

Although, if the que. was size of the chip, it is given by $128 * 8 = 2^{10}$

 

Ref : https://books.google.co.in/books?id=AIHgbyyEIHoC&pg=RA1-SA6-PA1&dq=number+of+data+lines+gives+word+size&hl=en&sa=X&ved=0ahUKEwir6qDGlO3oAhWPbysKHeLXBAcQ6AEIKjAA#v=onepage&q=number%20of%20data%20lines%20gives%20word%20size&f=false

Comments

Given 2 bits for chip select, if we assume 4 such chips to be present, the answer should be $2^7\times 2^2 = 2^9$

Answer 2

Given data,
address line=7
Data lines=8
Chip selected lines=2
Step-1: Total address lines are 2^7 and chips select lines
Step-2: The chips select lines are 2^2
Step-3: Total address and chip selected lines are 2^7 * 2^2 = 2^9
Step-4: Number of memory locations for 8 data lines =2^9 * 2^3
= 2^12

Comments

You're implying "address" and "memory locations" are different terms. Each address represent one memory location. @Arjun sir can you clarify?

Answer 3

Total number of memory locations will be

2*2^6*8 which is equal to 2^10.Because one address line of the address lines will be used to select one of the two chip selects.The remaining 6 address lines will be used to address one of the address location of the chip.And there are 8 data lines so each word of the chip is 8 bits long.