# Max Memory Space Addressed by 18 Address Bits

• needhelp83
In summary, the largest memory space that can be addressed by 18 addressing bits is 262,144 bytes, assuming each "memory location" holds one byte. This is calculated by taking 2 to the power of 18, which equals 262,144. However, it is important to note that not all chips may have memory locations for all of the addresses.
needhelp83
The largest memory space that can be addressed by 18 addressing bits is...

Is there a formula for this perhaps?

How many different combinations of 18 ones and zeros are there?

- Warren

2^n
n=18

2^18= 262,144

Would that be 262,144 bytes then

Assuming that each "memory location" holds one byte, yes.

Thanks for the help?

Something to note - while you might be able to have addresses going all the way up to 2^18 a lot of chips do not have memory locations for all of the addresses. Such as variants in the PIC16F8X range.

I noticed in a Digital Circuits book that with 18 address leads it should be 256K. So where does my 262,144 come from with 2^18. Just a thought?

256 * 1,024 = 262,144. The "k" in this context means 1,024, not 1,000.

- Warren

## What is the maximum memory space that can be addressed by 18 address bits?

The maximum memory space that can be addressed by 18 address bits is 262,144 bytes.

## How is the maximum memory space calculated from 18 address bits?

The maximum memory space is calculated by raising 2 to the power of the number of address bits. In this case, 2^18 = 262,144 bytes.

## Is 18 address bits enough to address all possible memory spaces?

No, 18 address bits is not enough to address all possible memory spaces. As technology advances and the need for larger memory spaces increases, more address bits are required to address all possible memory spaces.

## What are some devices or systems that use 18 address bits for memory addressing?

Some devices or systems that use 18 address bits for memory addressing include older computer systems, calculators, and other electronic devices with limited memory needs.

## Can 18 address bits be used to address other types of data besides memory?

Yes, 18 address bits can also be used to address other types of data, such as input/output ports, registers, and other hardware components within a computer system.

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