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From safety and chassis systems to body electronics and powertrain management, high-performance microcontrollers (MCUs) provide critical control and intelligence capabilities for today's automotive designs.
Mixed-signal 8-bit MCUs offer a variety of ways to streamline automotive system designs. By integrating a wide range of peripherals and communication protocols, such as controller area network (CAN) and local interconnect network (LIN), mixed-signal MCUs help minimize the need for additional discrete components.
From safety and chassis systems to body electronics and powerstrain management, high-performance microcontrollers (MCUs) provide critical control and intelligence capabilities for today's automotive designs. Mixed-signal MCUs are being designed into automotive systems to control more system features while reducing system design complexity, component count and board space.
In addition to reducing board space, on-chip integration can reduce component costs by as much as $0.70. Mixed-signal MCUs can eliminate the need for external components, such as voltage reference sources, regulators and resonators
A practical example is the C8051F58x 8-bit MCU family from Silicon Laboratories. This MCU family includes many on-chip peripherals not typically integrated on other 8-bit MCU alternatives.
Offering up to 128 kB of flash and 50 MIPS of processing power in a 25 mm2 package, the F58x family provides a combination of memory, performance and small size that enables automotive designers to solve problems that until now were expensive to address.
The F58x automotive MCUs provide internal oscillator accuracy to ±0.5% over the entire automotive grade 1 operating temperature (-40 to 125 °C) and voltage range. By using the on-chip analog-to-digital converter (ADC) and temperature sensor, a designer can further improve the accuracy to ±0.25% across the voltage and temperature range. Off-chip resonators cost an additional $0.20 to perform the same function. This capability enables designers to operate high-speed CAN and LIN networks without external timing components, reducing cost and improving system reliability.
Another unique feature of the integrated ADC is variable attenuation, which enables designers to dynamically attenuate the input signal to match the voltage reference. This technique has two distinct advantages:
• First, analog sensor signals greater than the voltage reference can take advantage of the full range of output codes. This means that desired signals will not be clipped and can take advantage of all output codes for the maximum amount of dynamic range.
• Second, part-to-part variation (i.e., calibration) in sensors can be eliminated, enabling designers to use lower cost sensors, calibrate them in-system and achieve the same performance as expensive precision sensors for a much lower system cost.
Dedicated automotive serial buses can also offer performance advantages to designers. For example, a high-speed CAN 2.0 engine that offers 32 discrete message objects can support heavy network traffic. By using the integrated LIN 2.1 controller (not LIN emulated in software), automotive designers can further improve network performance.
Automotive electronics engineers face more design options, more system performance requirements and more design complexity than ever before. Mixed-signal 8-bit MCUs can play an important role in simplifying the overall design effort, improving performance, reducing costs and addressing space constraints.
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