Auto Electronics

Making the right microcontroller architectural choice for embedded systems

The automotive electronics industry continues to expand its use of 8-bit and 16-bit microcontrollers (MCUs). With the MCU being the cornerstone of electronic control modules (ECMs), from safety systems to convenience systems to chassis systems to driver information systems to security systems, the appropriate 8-bit or 16-bit MCU supplier is critical for the embedded systems developer's ability to address future challenges. These microcontrollers occupy more than 75% of the microcontroller sockets within the automotive systems that have been architected for the vehicles of forthcoming model years. Among the challenges facing embedded-control design managers, two significant issues are:

  1. Getting projects to market quicker.
  2. Managing development costs.

Selecting the right 8-bit or 16-bit MCU architecture is a significant element of the development strategy for most automotive embedded-system developers, as well as the supply strategy for ECM manufacturers. The scope of MCU selection impacts many functions within a tier one company.

In an environment where automotive module manufacturers are reducing the number of suppliers in their base, selecting the appropriate 8-bit or 16-bit MCU goes beyond the analysis of available features, which can include:

  • memory technology and size options;
  • I/O pins;
  • on-chip peripherals;
  • system throughput;
  • power consumption;
  • package options.

Beyond feature sets, the suppliers of 8-bit and 16-bit microcontrollers are instrumental in providing designers with a flexible MCU architecture that offers compatible products that are easy to use and supported with development tools. Overall system performance requirements and the MCU budget will dictate which type of microcontroller — 8-bit or 16-bit — is appropriate for the ECM being developed. As a result, the most desirable microcontroller partner should have a user-friendly architecture as the basis for a family of compatible devices to address price/performance points across the spectrum from 8-bit to 16-bit microcontrollers for the system developer to make an MCU selection. Compatibility — software, peripheral and pinout — are key components of any microcontroller family in the quest to deliver embedded systems developers with a viable path to reduced development costs and quicker time to market.

Imagine that software routines used in an 8-bit mechatronics application, where an 8-pin MCU with 2 Kbytes of program memory is required. One advantage for the ECM maker would be a microcontroller vendor with a seamless migration path to allow 8-bit code to be re-used in a 16-bit body controller application where a 100-pin MCU with 256 Kbytes of program memory is required. The PIC MCU architecture, for example, supports this breadth of seamless software migration. An architecture with a seamless software migration path, coupled with compatible pinout support, puts the developer ahead in the drive to get products to market quicker and on budget. Software reuse is critical as it is an element to overcome the lack of embedded software development resources, which seems to face most ECM suppliers. With a development tool suite such as the MPLAB integrated development environment, the embedded-control developers are afforded a seamless development environment to enhance productivity. In the end, shorter development cycles can support lower development costs.

Flexibility is important to the developer of ECMs for the vehicle of tomorrow and is a “must-have” for their arsenal to be a survivor in the competitive and cost-conscious environment in today's market. Microcontroller suppliers with performance-oriented, compatible architectures provide the developer with alternatives to address market demands and challenges.


Dan Termer is vice president, Vertical Markets Group of Microchip Technology. Termer leads the Vertical Markets Group, which addresses the automotive, appliance and medical industry segments. In late 1998, he helped create the Microchip Automotive Products Group (APG).

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