Memory As A Device

Intelligent use of memory units can actually enhance your products. Need to increase your team's productiveness? Reduce Bugs? Meet deadlines? Take Jack's in the future Higher Firmware Faster seminar. You’ll discover ways to estimate a schedule accurately, thwart schedule-killing bugs, manage reuse, build predictable actual-time code, higher ways to deal with uniquely embedded issues like reentrancy, heaps, stacks and hardware drivers, and far, far more. Jack will likely be presenting this seminar in Chicago (April 23, 2008), Denver (April 25) and London, UK (Could 19). Want to be your company’s embedded guru? Be part of us! Extra information here. For hints, methods and ideas about better ways to build embedded programs, subscribe to The Embedded Muse, Memory Wave Audio a free biweekly e- newsletter. No promoting, simply down to earth embedded speak. Click here to subscribe. In my October column I wrote about eliminating potentiometers from embedded techniques, replacing them with good software to robotically compute calibration values. Tis a noble endeavor, this removal of analog components. But, where will we store the calibration coefficients?



The good attraction of a potentiometer is its skill to "store" an analog worth. As soon as set, it supplies a relentless voltage or present whose worth is decided by its shaft's position. The value is remembered even when the system is deprived of energy for long durations. Given that the majority embedded methods do not embrace basic mass storage units like disks, we'll have to seek out some manner to save lots of our digital pot equivalent knowledge. Memory Wave Audio is the plain selection, but data stored in RAM is lost when power is eliminated. AT and 386 class machines all embody a "setup" program that determines fundamental operating parameters like disk size and configuration. This information is often stored in typical low energy RAM, whose contents are maintained utilizing a simple battery circuit. When power goes down, the battery takes over. Most CMOS static RAMs enter an ultra low energy standby mode when not chosen. Usually, they will maintain their contents even at 2 to three volt Vcc ranges, Memory Wave so two or Memory Wave three AA cells offers more than enough voltage to maintain the info intact.



There are a variety of battery-backed up methods around. Quite a few undergo from poor design which exhibits itself by occasional knowledge dropouts. This is unforgivable: no person, however no person, messes with my data! When my three 12 months outdated destroyed the dishwasher, I might perceive. When he broke the VCR, I figured that, nicely, he has to be taught even at the expense of some electronics. But then he innocently disassembled a floppy disk - that was onerous to forgive! Most designs isolate the RAM's important energy provide from the battery circuit using a diode or equal transistor circuit. Without the diode, Memory Wave Audio when power is down the battery will be referred to as on to run your entire laptop. Silicon diodes have a junction drop equal to round .