Memory As A Machine

Clever use of memory units can actually improve your merchandise. Want to increase your group's productivity? Scale back Bugs? Meet deadlines? Take Jack's one day Better Firmware Sooner seminar. You’ll learn to estimate a schedule accurately, thwart schedule-killing bugs, manage reuse, construct predictable actual-time code, better ways to deal with uniquely embedded problems like reentrancy, heaps, stacks and hardware drivers, and far, Memory Wave Method much more. Jack will be presenting this seminar in Chicago (April 23, 2008), Denver (April 25) and London, Memory Wave UK (Might 19). Want to be your company’s embedded guru? Be part of us! Extra data here. For hints, tips and Memory Wave ideas about better methods to construct embedded techniques, subscribe to The Embedded Muse, a free biweekly e- newsletter. No advertising, just right down to earth embedded speak. Click right here to subscribe. In my October column I wrote about eliminating potentiometers from embedded methods, replacing them with sensible software to automatically compute calibration values. Tis a noble endeavor, this removal of analog components. However, where do we retailer the calibration coefficients?



The nice attraction of a potentiometer is its capability to "retailer" an analog value. As soon as set, it supplies a constant voltage or current whose worth is determined by its shaft's place. The value is remembered even when the system is deprived of energy for long durations. Given that the majority embedded methods do not embody traditional mass storage units like disks, we'll have to find some approach to save our digital pot equivalent information. Memory Wave Method is the plain alternative, however knowledge saved in RAM is misplaced when energy is eliminated. AT and 386 class machines all include a "setup" program that determines elementary working parameters like disk size and configuration. This info is normally stored in standard low power RAM, whose contents are maintained using a simple battery circuit. When power goes down, the battery takes over. Most CMOS static RAMs enter an extremely low power standby mode when not selected. Usually, they will maintain their contents even at 2 to three volt Vcc ranges, so two or Memory Wave Method three AA cells gives greater than sufficient voltage to maintain the information intact.



There are quite a lot of battery-backed up systems round. Fairly a number of endure from poor design which exhibits itself by occasional information dropouts. That is unforgivable: no one, but no one, messes with my information! When my three 12 months outdated destroyed the dishwasher, I might perceive. When he broke the VCR, I figured that, effectively, he has to learn even on the expense of some electronics. But then he innocently disassembled a floppy disk - that was arduous to forgive! Most designs isolate the RAM's primary energy provide from the battery circuit utilizing a diode or equal transistor circuit. Without the diode, when energy is down the battery will probably be known as on to run the whole computer. Silicon diodes have a junction drop equal to round .7 volts. A 5.0 volt supply will likely be solely 4.