Intelligent motor control can provide finer speed control and provide longer motor life— making it one of the hottest areas in electronics. Ramping up the speed of a motor, instead of hitting it with a full power surge, not only reduces the wear and tear on the motor, but can also make the product it is used in operate more smoothly. Once some intelligence is provided for motor control support, it’s possible to add more functions such as variable speed operation.

Motors come in a wide range of form factors and technologies. If you are looking for a good book on motors, check out "Electric Motors and Drives: Fundamentals, Types and Applications" by Austin Hughes (see ED# book review, ISBN: 0-7506-4718-3).

Motor control is typically relegated to microcontrollers with higher performance motors using digital signal controllers (DSC) or digital signal processors (DSP). In this article, I take a look at four 8-bit tools from Atmel, Cypress Semiconductor, Microchip and Zilog.

The typical motor control kit includes a board that has power transistors (since most microcontrollers cannot drive a motor directly). Likewise, motor feedback mechanisms are sometimes available (see "Smart Motion Makes For A Smarter Design," ED Online ID #11294). The kinds of microcontrollers mentioned in this article are suitable for handling small to medium sized motors of various types.

Atmel

Atmel’s motor control support consists of a number of application notes, along with the company’s standard development tools suite. I checked out the AVR Fan Controller board, which can be controlled externally in the same manner employed with Atmel’s Butterfly board (see Fig. 1). I also got my hands on the more robust ATAVRMC100 Brushless DC Motor Evaluation Kit (see Fig. 2).

The ATAVRMC100 features a small board that houses the power electronics (8 to16V DC at 4A) and an AVR AT90PWM3 microcontroller. The AT90PWM3 has 8Kbytes of flash, 512 bytes of SRAM, and 512 bytes of EEPROM. It also has a 10-channel advanced PWM, an 11-channel 8-bit ADC, a 10-bit ADC with programmable gain, a 10-bit DAC, a pair of 12-bit PSC (power stage controllers) with 4-bit resolution enhancement and DALI protocol support. Serial communications support also handles LIN (Local Interconnect Network).