basic pwm

jonatan rojas

i need help, i have to control the position dc motor with encoder, i can not find a code with basic use to pwm to tivac tm4c123g6pm i used code composer to programming

over 8 years ago

0 Bob Crosby over 8 years ago

TI__Guru 72500 points

If you download the TivaWare drivers, you will find some examples for the PWM in:
C:\ti\TivaWare_C_Series-2.1.4.178\examples\peripherals\pwm

0 jonatan rojas over 8 years ago in reply to Bob Crosby

Prodigy 90 points

i try first to control the speed,

this is my code

#include <stdint.h>
#include <stdbool.h>
#include "inc/hw_memmap.h"
#include "inc/hw_types.h"
#include "driverlib/sysctl.h"
#include "driverlib/gpio.h"
#include "driverlib/debug.h"
#include "driverlib/pwm.h"
#include "driverlib/pin_map.h"
#include "inc/hw_gpio.h"
#include "driverlib/rom.h"
#include "driverlib/adc.h"

#define PWM_FREQUENCY 55

int main(void)
{
    volatile uint32_t ui32Load;
    volatile uint32_t ui32PWMClock;
    uint32_t ui32ADC0Value[1];
    volatile uint8_t ui8Adjust;

    SysCtlClockSet(SYSCTL_SYSDIV_5|SYSCTL_USE_PLL|SYSCTL_OSC_MAIN|SYSCTL_XTAL_16MHZ);
    SysCtlPWMClockSet(SYSCTL_PWMDIV_64);

    SysCtlPeripheralEnable(SYSCTL_PERIPH_PWM1);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOD);

    GPIOPinTypePWM(GPIO_PORTD_BASE, GPIO_PIN_0);
    GPIOPinConfigure(GPIO_PD0_M1PWM0);

    ui32PWMClock = SysCtlClockGet() / 64;
    ui32Load = (ui32PWMClock / PWM_FREQUENCY) - 1;
    PWMGenConfigure(PWM1_BASE, PWM_GEN_0, PWM_GEN_MODE_DOWN);

    PWMGenPeriodSet(PWM1_BASE, PWM_GEN_0,ui32Load );

    PWMOutputState(PWM1_BASE, PWM_OUT_0_BIT, true);
    PWMGenEnable(PWM1_BASE, PWM_GEN_0);

    SysCtlPeripheralEnable(SYSCTL_PERIPH_ADC0);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOE);
    GPIOPinTypeADC(GPIO_PORTE_BASE,GPIO_PIN_3);
    ADCSequenceConfigure(ADC0_BASE, 3, ADC_TRIGGER_PROCESSOR, 0);
    ADCSequenceStepConfigure(ADC0_BASE, 3, 0, ADC_CTL_CH0 | ADC_CTL_IE |ADC_CTL_END);

    ADCSequenceEnable(ADC0_BASE, 3);

    while(1)
    {

        ADCIntClear(ADC0_BASE, 3);
        ADCProcessorTrigger(ADC0_BASE, 3);

          while(!ADCIntStatus(ADC0_BASE, 3, false))
          {
          }

          ADCSequenceDataGet(ADC0_BASE, 3, ui32ADC0Value); // Watch on ui32ADC0Value
          ui8Adjust=ui32ADC0Value[0];

           PWMPulseWidthSet(PWM1_BASE, PWM_OUT_0, ui8Adjust * ui32Load / 500);

           SysCtlDelay(100000);
     }

    }

but i think the problem in this line PWMPulseWidthSet(PWM1_BASE, PWM_OUT_0, ui8Adjust * ui32Load / 500) the motor change the speed but not normal

0 Bob Crosby over 8 years ago in reply to jonatan rojas

TI__Guru 72500 points

Ignoring the motor, is the PWM signal the correct frequency and pulse width?

0 jonatan rojas over 8 years ago in reply to Bob Crosby

Prodigy 90 points

i dont know, how can i calculate the parameters

0 Bob Crosby over 8 years ago in reply to jonatan rojas

TI__Guru 72500 points

Perhaps we should start at the beginning. What type of motor are you trying to control? What is the frequency of the PWM signal you want? How do you determine the duty cycle you want?

0 jonatan rojas over 8 years ago in reply to Bob Crosby

Prodigy 90 points

i am using a dc motor, the frequency i dont know, i only want to control speed of motor for example

PWM1_Init(5000);

PWM1_Start();

while(1)
{
pot=adc_read(0)>>2;
PWM1_Set_Duty(pot);
delay_ms(30);
}

this is what I want to do

0 Bob Crosby over 8 years ago in reply to jonatan rojas

TI__Guru 72500 points

I have attached a CCS7.3 project that reads the value on AIN0 and outputs a PWM on M0PWM2 at 40KHz..

/cfs-file/__key/communityserver-discussions-components-files/81/Forum646554.zip

Code Composer Studio™︎

Code Composer Studio forum

basic pwm