HPWMUpdate for CCP/PWM Modules(s)

Syntax:

    HPWMUpdate ( channel, duty_cycle )

Command Availability:

Available on Microchip PIC microcontrollers with the CCP module.

Explanation:

This command updates the duty cycle only.

  • You MUST have previously called the HPWM CCP command using the full command to set the channel specific settings for frequency and timer source.  See the example below for the usage.
  • You MUST specify the constant #define HPWM_FAST to support HPWMUpdate when using CCP module.

This command only supports the previously called HPWM CCP command, or, if you have set more than one HPWM CCP channel then to use the command you must have set the channel to the same frequency.

The command only supports the CCP module of the Microchip PIC microcontroller to generate a PWM waveform at the previously defined frequency and timer source.

channel is 1, 2, 3, 4 or 5. These corresponds to the CCP1 through to CCP5 respectively.  The channel MUST be supported by the microcontroller.   Check the microcontroller specific datasheet for the available channel.

duty cycle specifies the desired duty cycle of the PWM signal, and ranges from 0 to 255 where 255 is 100% duty cycle.

Example for CCP PWM:

    'This program will alter the brightness of an LED using
    'hardware PWM.

    #chip 16F1938
    #option Explicit

    'Set the direction of the CCP/PWM port
    DIR portc.2 Out

    #define HPWM_FAST           'Required to support HPWMUpdate when using CCP module
    HPWM 1, 40, dutyvalue

    do
        'use for-loop to show the duty changing a 8bit value
        dim dutyvalue as byte
        for dutyvalue = 0 to 255
            HPWMUpdate 1, dutyvalue
            wait 10 ms
        next
        for dutyvalue = 254 to 1
            HPWMUpdate 1, dutyvalue
            wait 10 ms
        next
    loop

For more help, see PWMOff

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