The Why, What, How and When of Using Microprocessor Supervisors

Abstract: This tutorial explains why supervisory circuits are important. We discuss the many problems associated with microprocessor system and how designers can protect from some of these systems through hardware. Common problems such as power supplies that come up in the wrong sequence, ramp up or stabilize too slowly; supply voltages that glitch up and down due to external-component loads; or peripheral components and boards that fail to power up and communicate in synchronization with the needs of the processor. System level designers, can to minimize these events that cause microprocessors to hang-up or create faulty operations when a problem occurs. Through the use of a supervisory circuit we can be sure our microprocessor-based system starts properly every time; that it detects when a system error has occurred or is about to occur; that the system minimizes the effect of these errors; and that it returns safely from an error with little or no user intervention.