designdigital-logicmemory
Note1: I know that the 16 X 4 memory contains 4 output lines. there is also a 4-bit input to construct the 16 WORDS.
Note2: The problem arises as the RAM 32 X 8 contains 8 output lines and 5-bit input. But i want to use 4 of RAM 16 X 4.
Question: What can i do about my design to get the RAM 32 X 8 with correct input and output lines.
When talking about internal memory in mobile phones they usually mean Flash memory. This is the memory which holds your system software (operating system and such) and the applications. This memory is non-volatile, which means that data is retained even when power is switched off. That's what you want, otherwise your phone would become worthless if the battery is drained.
RAM is volatile memory, which means that the content is gone when the power is switched off. This is used by the OS and the applications to hold their temporary content, which becomes irrelevant if the device is switched off and/or which easily can be reconstructed.
The solution is found by searching for "encoder" on Wikipedia:
Key point, the only valid inputs are when exactly one of the inputs is high. That means there are lots of don't cares in the output columns of the truth table.
Best Answer
You double the number of addresses by using the high order address bit to generate a chip select (If you also have a chip select line then use logic gates to combine it with the address line). You double the number of bits by putting two chips in parallel. Same address and control lines to both of them but different data lines.
simulate this circuit – Schematic created using CircuitLab