Using a microcontroller for motor control is an attractive alternative to Application-Specific Standard Products (ASSP) as they are often too specific and limited for the target application. Consequently Atmel has expanded AVR microcontroller support to AC and Brushless DC (BLDC) motor control applications.
Ranging from 8 to 100 pin devices, AVR Flash microcontrollers are suited to simple applications such as PC fans as well as advanced motor control applications. All AVR's incorporate a Flash program memory and an EEPROM enabling the designer to use the same microcontroller for multiple designs and to install the latest programs at any time during product life cycle.
The code compatibility of AVR allows designers to port their development to other AVR devices. This flexibility results in shorter time to market and helps minimise system cost.
Motor control is realised by internal timers with Pulse Width Modulation (PWM), Analogue-Digital Converter (ADC) and I/Os with interrupt. The PWM handles the voltage pattern applied to the motor and facilitates speed and acceleration control.
The onboard 10bit ADC measures power consumption and provides over-current warnings while the AVR's pin-change interrupt monitors the Hall sensors of the BLDC. The AVR's ADC and Analogue Comparator predict the position of the motor for sensor-less BLDC.