Memory Interfaces

For all the different kinds of memory chips in existence, there's no standard way to connect these chips to other chips in a system. Flash ROMs, EEPROMs, DRAMs, and SRAMs all connect in different and incompatible ways to microprocessors and other chips. Figuring out ways to make these chips all work together is one of the reasons electrical engineers get paid so well.

ROMs are generally used as low-speed devices, so the problem isn't so bad. Many products that use ROM chips aren't particularly performance sensitive, so getting data out of the ROM in a quick and timely manner often isn't important. RAMs are another matter.

RAMs, and especially DRAMs, are used mostly in computer systems where speed and low cost are paramount. It's important, therefore, to come up with a quick and reliable way to connect fast DRAMs to even faster microprocessors. Transmitting data bits back and forth between these two chips at high speed is a science unto itself, and many different methods have emerged. Most of these are arcane topics best suited for engineering conferences.