Capture/Compare/PWM(CCP) Module in PIC18FXXX Microcontroller

With the world so heavily dependent on embedded systems, microcontrollers have become indispensable devices in embedded design. A microcontroller (MCU) is a device that combines the core of a microprocessor (MPU) with features such as I/O ports, timers, some dedicated communication controllers, etc. Whereas an MPU needs additional glue logic to interface to the outside world, an MCU is a self-sufficient device as far as Peripheral handling is concerned, due to the availability of rich on-chip resources. Depending on a specific application, the choice of an appropriate MCU can indeed lead to a very efficient design. This course is a brief introduction giving an insight into the PIC18FXXX MCU and is aimed to explain the CCP module and PWM programming.

Indeed the PWM is so widely used that Microchip has enhanced the PWM capabilities of the newer generation of the PIC18 family members and has designated them as ECCP(enhanced CCP). The main difference between ECCP and CCP is the PWM capability.

The speed of the motor depends on three factors: load, voltage, and current. By changing the width of the pulse applied to the Dc motor we can increase or decrease the amount of power provided to the motor, thereby increasing or decreasing the motor speed. The ability to control the speed of the DC motor using PWM is one reason that DC motors are preferable to AC motors. We use the PWM feature of the CCP to control DC motors.