RAM Random Access Memory for Embedded Systems
- Random Access memory, RAM is used in embedded system and all computer systems as a temporary form of storage.
The Random Access memory, RAM is a key element of any computer system, whether an embedded system or a large mainframe.The RAM, random access memory is used to store temporary data within the embedded system. Programme variables and other temporary data is generally stored within the RAM.
The name comes from the fact that data can be accessed as required from random locations within the memory. The RAM allows data items to be read and written in roughly the same amount of time regardless of the order in which data items are accessed.
Random access memory basics
The various forms of random access memory, RAM, that are used within embedded systems are almost always volatile forms of memory, i.e. information stored within them is lost if the power is removed.
There are two main forms of RAM that are used:
- Static RAM, SRAM: An SRAM is more expensive and less dense than DRAM. It uses a memory cell comprising of six transistors. However it is faster and requires less power. As a result it is often used as a cache memory in many forms of computer.
- Dynamic RAM, DRAM: A DRAM cell consists of a transistor and capacitor pair. The capacitor holds a high or low charge equating to a logic state 1 or 0 and the transistor acts as a switch that lets the control circuitry on the chip read the capacitor's state of charge or change it. Requiring many fewer components per memory cell, a DRAM is less expensive to produce than SRAM. As a result DRAM is the predominant form of memory used in computers and embedded systems for RAM applications.
By Ian Poole
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