Using Hardware PWM on Tiva Launchpad

[lawrence_jeff 3]

PWM is much easier on the new Launchpad using the PWM peripherals, here is a working example using the 3 onboard LEDs.

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

int
main(void)
{    unsigned long ulPeriod;

    //Set the clock
   SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_OSC |   SYSCTL_OSC_MAIN | SYSCTL_XTAL_16MHZ);

   //Configure PWM Clock to match system
   SysCtlPWMClockSet(SYSCTL_PWMDIV_1);

   // Enable the peripherals used by this program.
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_PWM1);  //The Tiva Launchpad has two modules (0 and 1). Module 1 covers the LED pins
    ulPeriod = SysCtlClockGet() / 200; //PWM frequency 200HZ

    //Configure PF1,PF2,PF3 Pins as PWM
    GPIOPinConfigure(GPIO_PF1_M1PWM5);
    GPIOPinConfigure(GPIO_PF2_M1PWM6);
    GPIOPinConfigure(GPIO_PF3_M1PWM7);
    GPIOPinTypePWM(GPIO_PORTF_BASE, GPIO_PIN_1 | GPIO_PIN_2 | GPIO_PIN_3);

    //Configure PWM Options
    //PWM_GEN_2 Covers M1PWM4 and M1PWM5
    //PWM_GEN_3 Covers M1PWM6 and M1PWM7 See page 207 4/11/13 DriverLib doc
    PWMGenConfigure(PWM1_BASE, PWM_GEN_2, PWM_GEN_MODE_UP_DOWN | PWM_GEN_MODE_NO_SYNC); 
    PWMGenConfigure(PWM1_BASE, PWM_GEN_3, PWM_GEN_MODE_UP_DOWN | PWM_GEN_MODE_NO_SYNC); 

    //Set the Period (expressed in clock ticks)
    PWMGenPeriodSet(PWM1_BASE, PWM_GEN_2, ulPeriod);
    PWMGenPeriodSet(PWM1_BASE, PWM_GEN_3, ulPeriod);

    //Set PWM duty-50% (Period /2)
    PWMPulseWidthSet(PWM1_BASE, PWM_OUT_5,ulPeriod/2);
    PWMPulseWidthSet(PWM1_BASE, PWM_OUT_6,ulPeriod/2);
    PWMPulseWidthSet(PWM1_BASE, PWM_OUT_7,ulPeriod/2);

    // Enable the PWM generator
    PWMGenEnable(PWM1_BASE, PWM_GEN_2);
    PWMGenEnable(PWM1_BASE, PWM_GEN_3);

    // Turn on the Output pins
    PWMOutputState(PWM1_BASE, PWM_OUT_5_BIT |PWM_OUT_6_BIT|PWM_OUT_7_BIT, true);

    //Do nothing
    while(1)
    {

    }

}

[peppeg85 0]

hi, i'm studying the pwm on a lm4f120hq, when I build the main.c i've the following error:

 

#20 identifier "GPIO_PF1_M1PWM5" is undefined 

 

it is about the lines:

 

//Configure PF1,PF2,PF3 Pins as PWM
GPIOPinConfigure(GPIO_PF1_M1PWM5);
GPIOPinConfigure(GPIO_PF2_M1PWM6);
GPIOPinConfigure(GPIO_PF3_M1PWM7);

 

how can I solve this problem?

 

THANKS!!!
 

[peppeg85 0]

searching in the internet i found the following site:

http://codeandlife.com/2012/10/30/stellaris-launchpad-pwm-tutorial/

is better to use the timers as pwm modules due the absence of a dedicated pwm module??

[lawrence_jeff 3]

searching in the internet i found the following site:

http://codeandlife.com/2012/10/30/stellaris-launchpad-pwm-tutorial/

is better to use the timers as pwm modules due the absence of a dedicated pwm module??

If you are using a stellaris launchpad that is your only option. My code example was for a tiva launchpad which has the pwm module.

[peppeg85 0]

ok, thanks!

[RAKSH 1]

Unfortunately ,I'm not getting any PWM output on the Led's  ,
I copy pasted the same code .


 

[superbrew 0]

Unfortunately ,I'm not getting any PWM output on the Led's  ,

I copy pasted the same code .

 

 

 

This code worked for me. Are you getting any errors or warnings?

[RAKSH 1]

No I tried it again ,
I am not getting any errors and warnings .

What am i expected to observe in the LED's

I just see a whitish light without any fading .
I tried matching the dutycycle and changing the period according to my needs to achieve fading  ,but to no avail .

[thequila 0]

Solving undefined identifiers error:

#define GPIO_PB6_M0PWM0         0x00011804
#define GPIO_PB7_M0PWM1         0x00011C04
#define GPIO_PB4_M0PWM2         0x00011004
#define GPIO_PB5_M0PWM3         0x00011404
#define GPIO_PE4_M0PWM4         0x00041004
#define GPIO_PE5_M0PWM5         0x00041404
#define GPIO_PF1_M1PWM5         0x00050405
#define GPIO_PF2_M1PWM6         0x00050805
#define GPIO_PF3_M1PWM7         0x00050C05

[bluehash 1,578]

 

Solving undefined identifiers error:

#define GPIO_PB6_M0PWM0         0x00011804
#define GPIO_PB7_M0PWM1         0x00011C04
#define GPIO_PB4_M0PWM2         0x00011004
#define GPIO_PB5_M0PWM3         0x00011404
#define GPIO_PE4_M0PWM4         0x00041004
#define GPIO_PE5_M0PWM5         0x00041404
#define GPIO_PF1_M1PWM5         0x00050405
#define GPIO_PF2_M1PWM6         0x00050805
#define GPIO_PF3_M1PWM7         0x00050C05

Did you include the gpio.h file and driverlib?

[thequila 0]

Yes. gpio.h uses pin_map.h, which has no declaration of these pins for StellarisPad (at least in energia). I took those #defines directly from TivaWare C Series 1.1 pin_map.h. It seems to work for Tiva pads.

[Bernard 7]

Hi,

 

I tried porting it to Energia  TIVA board :

#include <stdint.h>
#include <stdbool.h>
#include "inc/hw_gpio.h"
#include "inc/hw_types.h"
#include "inc/hw_memmap.h"
#include "driverlib/sysctl.h"
#include "driverlib/pin_map.h"
#include "driverlib/gpio.h"
#include "driverlib/pwm.h"
#include "inc/tm4c123gh6pm.h" //added

void setup()
{   
     unsigned long ulPeriod;

    //Set the clock
   SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_OSC |   SYSCTL_OSC_MAIN | SYSCTL_XTAL_16MHZ);

   //Configure PWM Clock to match system
   SysCtlPWMClockSet(SYSCTL_PWMDIV_1);

   // Enable the peripherals used by this program.
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_PWM1);  //The Tiva Launchpad has two modules (0 and 1). Module 1 covers the LED pins
    ulPeriod = SysCtlClockGet() / 200; //PWM frequency 200HZ

    //Configure PF1,PF2,PF3 Pins as PWM
    GPIOPinConfigure(GPIO_PF1_M1PWM5);
    GPIOPinConfigure(GPIO_PF2_M1PWM6);
    GPIOPinConfigure(GPIO_PF3_M1PWM7);
    GPIOPinTypePWM(GPIO_PORTF_BASE, GPIO_PIN_1 | GPIO_PIN_2 | GPIO_PIN_3);

    //Configure PWM Options
    //PWM_GEN_2 Covers M1PWM4 and M1PWM5
    //PWM_GEN_3 Covers M1PWM6 and M1PWM7 See page 207 4/11/13 DriverLib doc
    PWMGenConfigure(PWM1_BASE, PWM_GEN_2, PWM_GEN_MODE_UP_DOWN | PWM_GEN_MODE_NO_SYNC); 
    PWMGenConfigure(PWM1_BASE, PWM_GEN_3, PWM_GEN_MODE_UP_DOWN | PWM_GEN_MODE_NO_SYNC); 

    //Set the Period (expressed in clock ticks)
    PWMGenPeriodSet(PWM1_BASE, PWM_GEN_2, ulPeriod);
    PWMGenPeriodSet(PWM1_BASE, PWM_GEN_3, ulPeriod);

    //Set PWM duty-50% (Period /2)
    PWMPulseWidthSet(PWM1_BASE, PWM_OUT_5,ulPeriod/2);
    PWMPulseWidthSet(PWM1_BASE, PWM_OUT_6,ulPeriod/2);
    PWMPulseWidthSet(PWM1_BASE, PWM_OUT_7,ulPeriod/2);

    // Enable the PWM generator
    PWMGenEnable(PWM1_BASE, PWM_GEN_2);
    PWMGenEnable(PWM1_BASE, PWM_GEN_3);

    // Turn on the Output pins
    PWMOutputState(PWM1_BASE, PWM_OUT_5_BIT |PWM_OUT_6_BIT|PWM_OUT_7_BIT, true);
}
   
    void loop()
    {

    }

I get errors:

pwmtiva.ino:28:22: error: 'GPIO_PF1_M1PWM5' was not declared in this scope
apwmtiva.ino:29:22: error: 'GPIO_PF2_M1PWM6' was not declared in this scope
apwmtiva.ino:30:22: error: 'GPIO_PF3_M1PWM7' was not declared in this scope

I don't understand because GPIO_PF1_M1PWM5, GPIO_PF1_M1PWM6, GPIO_PF1_M1PWM7 are defined in driverlib/pin_map.h.

Thanks for help.

Salutations.

Bernard

[Bernard 7]

Hi again,

 

Just put  #define PART_TM4C123GH6PM before #includes.

It compiles and load but no pwm effect ....
 

[gonya707 2]

Hi @@brownfox

 

 I think you have to include PART_TM4C123GH6PM here, in the project properties, under predefined symbols:

 

 

In your case use PART_TM4C123GH6PM instead of the LM4F120.

 

Happy Christmas

[Bernard 7]

hi,

 

Thanks gonya707 but I don't use CCS.

 

Just trying to port your example to Energia.

 

happy Christmas

 

Bernard.