Pulse-Width Modulation

• The widely used edge-aligned PWM offers simple configuration, fast response and higher resolution
• The center-aligned PWM is extremely helpful in reducing the harmonics in the output of motor control, power supply and other applications
• Some select devices can even generate variable-aligned PWM, which serves applications that require higher flexibility

Although they are designed slightly differently for each architecture, the PWM peripherals available in PIC^® and AVR^® microcontrollers (MCUs) provide your system with a hardware-driven PWM generator that does not occupy any CPU resources at runtime. They also have built-in hardware to accommodate PWM-related tasks such as dead-band delay and auto shutdown. To generate complex waveform outputs, the PWM peripheral can be used with other on-chip peripherals, such as the Complementary Waveform Generator (CWG), Configurable Custom Logic (CCL) or Configurable Logic Cell (CLC). PWM peripherals can be easily configured with MPLAB^® Code Configurator (MCC) for PIC MCUs and Atmel START for AVR MCUs. 

PIC MCUs offer a variety of stand-alone PWM peripherals ranging from 10–16 bits that are designed to integrate and interface with different peripherals like timers. The standard PWM peripheral generates a PWM signal with a modifiable period and duty cycle duty. A variety of clock sources can be used to operate the PWM, and it can be used in low-power sleep modes when an external clock source is being used.

The Capture/Compare PWM (CCP) module is an extremely versatile peripheral that offers multiple modes of operation. In PWM mode, it can operate as a PWM peripheral, and in capture mode it can measure PWM characteristics such as the edges of waveforms. In compare mode, it can also compare its internal timer values to user-defined values to trigger other peripherals or generate an interrupt.

Select  8-bit PIC MCUs offer a 16-bit PWM that uses an independent Timer source and can generate various output signals. This PWM peripheral is extremely useful for dynamic high-resolution lighting control and push-pull amplifiers.

The PWM module has a compare feature and multiple outputs. The outputs are grouped in slices with each slice having two outputs where both share the same PWM period and operating mode. Different slices can utilize different operating modes. There are six operating modes: Left Aligned, Right Aligned, Center Aligned, Variable Aligned, Pulsed Compare, Toggled Compare. The left and right aligned modes can also be operated in Push-Pull mode.

• Get Atmel START examples using the PWM
• Get MPLAB^® Xpress examples using the PWM
• Get tutorials on Timers