New chips make it easier for automakers to electronically control doors, seats, lighting, and HVAC Jim Williams, 16-Bit Applications Section Leader Eight-bit microcontrollers have historically handled simple tasks on vehicles such as controlling window lift motors. Though these components worked well in the past, they run out of steam for some of today's more sophisticated automotive uses. Increasingly, complex applications in automotive body-control applications demand the higher performance of 16-bit microcontrollers. Traditionally mechanical systems such as doors, seating, interior lighting, and ventilation are becoming electronically defined. Moreover, these electronic systems increasingly interact with each other in some way. This has brought a need for gateway interfaces between systems to allow information sharing and interaction. Sixteen-bit MCUs can handle these tasks by managing multiple serial interfaces such as Controller-area networks (CAN), Local-interconnect network (LIN) buses, and Serial-peripheral interfaces (SPI). These processes also have the horsepower to handle large control programs written in high-level languages. Even seemingly simple control nodes can require a fair amount of processing power. An outside rearview mirror serves as an example. Aside from the actual control functions, mirror circuits must be able to withstand wide temperature swings and serious power problems like jump-start (up to 40 V) and reverse battery. A full-featured mirror can have three operational motors (vertical tilt, horizontal tilt, and automatic folding), a heater, a sensor to know when to use the heater, a turn-signal lamp, and a puddle lamp. In addition, the mirror needs information from systems elsewhere in the car. For one thing, it needs data from the turn-signal lever to control the turn lamp. It also needs to talk with the door-open switch and possibly an ambient light sensor to determine whether or not to illuminate the puddle light. Such a control node probably would be handled by an eight-bit MCU. It
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Current Testers and Detectors
Current testers and detectors check for the presence of current flow in electrical circuits. They are also used to locate current in hidden wires and cables
Power meters are used for high-accuracy measurements of power over a wide-frequency bandwidth, and from both AC and DC circuits.
Clamp meters are ammeters that can measure current without the need to disconnect the wires where the measurement occurs. They provide information about current draw and current continuity in order to help users troubleshoot erratic loads and trends.
Voltage testers check for difference in potential in electrical circuits.
Programmable Power Supplies
Programmable power supplies are digitally controlled power sources that provide accurate and adjustable levels of voltage, current, and frequency. They include a processor, voltage/current programming circuits, current shunt, and voltage/current read-back circuits.
Topics of Interest
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8.2 GAIN AND LEVEL TESTS
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