Random-access memory: Difference between revisions

Revision as of 20:33, 18 March 2025

Revision as of 23:04, 20 March 2025

Line 73:

==Addressing==

To be useful, memory cells must be readable and writable. Within the RAM device, multiplexing and demultiplexing circuitry isare used to select memory cells. Typically, a RAM device has a set of address lines <math>A_0, A_1,...A_n</math>, and for each combination of bits that may be applied to these lines, a set of memory cells are activated. Due to this addressing, RAM devices virtually always have a memory capacity that is a power of two.

Usually several memory cells share the same address. For example, a 4 bit "wide" RAM chip has four memory cells for each address. Often the width of the memory and that of the microprocessor are different, for a 32 bit microprocessor, eight 4 bit RAM chips would be needed.