1.10.13 1.11.14 1.12.14 1.13.13 Motor Control Pulse-Width Modulation (MCPWM)

The PIC32MK GP/MC Family of devices support a dedicated Motor Control Pulse-Width Modulation (PWM) module with up to 12 outputs. The Motor Control PWM module consists of the following major features:

  • Two master time base modules with special event triggers

  • PWM module input clock prescaler

  • Two synchronization inputs

  • Two synchronization outputs

  • Eight PWM generators with complimentary output pairs

  • Four additional PWM generators with single ended outputs

  • Period, duty cycle, phase shift and dead time minimum resolution of 1 / FSYSCLK in Edge-Aligned mode and 2 / FSYSCLK minimum resolution in Center-Aligned mode

  • Cycle by cycle fault recovery and latched fault modes

  • PWM time-base capture upon current limit

  • Nine fault input pins are available for faults and current limits

  • Programmable analog-to-digital trigger with interrupt for each PWM pair

  • Complementary PWM outputs

  • Push-Pull PWM outputs

  • Redundant PWM outputs

  • Edge-Aligned PWM mode

  • Center-Aligned PWM mode

  • Variable Phase PWM mode

  • Multi-Phase PWM mode

  • Fixed-Off Time PWM mode

  • Current Limit PWM mode

  • Current Reset PWM mode

  • PWMxH and PWMxL output override control

  • PWMxH and PWMxL output pin swapping

  • Chopping mode (also known as Gated mode)

  • Dead time insertion

  • Dead time compensation

  • Enhanced Leading-Edge Blanking (LEB)

  • 15 mA PWM pin output drive

Using The Library

This example shows how to configure the MCPWM to generate PWM signals whose duty and period can be configured independently.

/* Duty cycle increment value */
#define DUTY_INCREMENT (10U)

/* Save PWM period */
uint16_t period;

/* This function is called after PWM0 counter event */
void PWM_PeriodHandler(uint32_t status, uintptr_t context)
{
    /* duty cycle values */
    static uint16_t duty0 = 0U;
    static uint16_t duty1 = 1000U;
    static uint16_t duty2 = 2000U;

    MCPWM_ChannelPrimaryDutySet(MCPWM_CH_1, duty0);
    MCPWM_ChannelPrimaryDutySet(MCPWM_CH_2, duty1);
    MCPWM_ChannelPrimaryDutySet(MCPWM_CH_3, duty2);
    
    /* Increment duty cycle values */
    duty0 += DUTY_INCREMENT;
    duty1 += DUTY_INCREMENT;
    duty2 += DUTY_INCREMENT;
    
    if (duty0 > period)
        duty0 = 0U;
    if (duty1 > period)
        duty1 = 0U;
    if (duty2 > period)
        duty2 = 0U;
}

int main ( void )
{
    /* Initialize all modules */
    SYS_Initialize ( NULL );
    
    /* Register callback function for Channel 0 counter event */
    MCPWM_CallbackRegister(MCPWM_CH_1, PWM_PeriodHandler, (uintptr_t)NULL);
    
    /* Read the period */
    period = MCPWM_PrimaryPeriodGet();
    
    /* Start all synchronous channels by starting channel 0*/
    MCPWM_Start();

    while ( true )
    {
        /* Maintain state machines of all polled MPLAB Harmony modules. */
        SYS_Tasks ( );
    }

    /* Execution should not come here during normal operation */

    return ( EXIT_FAILURE );
}

Library Interface

Peripheral library provides the following interfaces:

Functions

Name Description
MCPWM_Initialize Initializes given instance of MCPWM peripheral
MCPWM_Start Starts the MCPWM module
MCPWM_Stop Stops the given MCPWM module
MCPWM_PrimaryPeriodSet Sets the period value of the primary time base
MCPWM_SecondaryPeriodSet Sets the period value of the secondary time base
MCPWM_PrimaryPeriodGet Reads the period value of primary time base generator
MCPWM_SecondaryPeriodGet Reads the period value of secondary time base generator
MCPWM_ChannelPrimaryDutySet Writes the primary duty cycle value of given MCPWM channel
MCPWM_ChannelSecondaryDutySet Writes the secondary duty cycle value of given MCPWM channel
MCPWM_ChannelDeadTimeSet Writes dead time values of given MCPWM channel
MCPWM_ChannelPrimaryTriggerSet Writes the primary trigger compare value to trigger ADC conversion
MCPWM_ChannelSecondaryTriggerSet Writes the secondary trigger compare value to trigger ADC conversion
MCPWM_PrimaryEventCallbackRegister Registers the function to be called from interrupt
MCPWM_SecondaryEventCallbackRegister Registers the function to be called from interrupt
MCPWM_CallbackRegister Registers the function to be called from interrupt
MCPWM_ChannelPinsOverrideEnable Enables PWM output pins override function
MCPWM_ChannelPinsOverrideDisable Disables PWM output pins override function
MCPWM_ChannelPinsOwnershipEnable Sets the PWM output pins ownership to PWM generator
MCPWM_ChannelPinsOwnershipDisable Sets the PWM output pins ownership to GPIO

Data types and constants

Name Type Description
MCPWM_CH_CALLBACK Typedef Defines the data type and function signature for the MCPWM peripheral callback function
MCPWM_CALLBACK Typedef Defines the data type and function signature for the MCPWM peripheral callback function for primary event and secondary event
MCPWM_CH_NUM Enum Identifies MCPWM channel number in a MCPWM peripheral
MCPWM_CH_STATUS Enum Identifies MCPWM channel event status