LPC5536 PMW register update issue

[jimmyli]

Hi,

      We are developing a project by LPC3336, a question shown below.

      Hope you can help to check and fix.

     1>LPC5536 PMW0 SM0 configuration

      2>Question

           "Immediate"  can't take effect soon when set LDOK ( LDMOD is set to 1), we can't find the reason.

      Thanks very much.

[Alice_Yang]

Hello,

I tested on my side, when set 

pwmConfig.reloadLogic = kPWM_ReloadImmediate;

The reload value can take effect immediately.

I used the project you send to me, and just change gpio on my side. Full speed run can not analysis it,

use breakpoint and step debug.

1) Set a breakpoint at 

2) After run at here, click step over:

3)Click Run, check signal:

Yellow: GPIO

Green: PWM.

Also you can change "pwmConfig.reloadLogic " to other configurations, observe result.

BR

Alice

[明省徐]

Hi,Alice_Yang:

    I test again in EVK board,but result is not except. result show in picture, Also use the project.

[明省徐]

Hello,Alice_Yang：

  I followed your steps, but the results were not as expected and were the same as the pictures I uploaded when I asked questions.

The mcu I tested is LPC5536, Can you share what your MCU is?

[Alice_Yang]

Hello @jimmyli 

1) Please check register SM0CTRL, whether set LDMOD to 1.

2)Test with SDK demo "PWM", default  configuration is 

/* Use full cycle reload */
pwmConfig.reloadLogic = kPWM_ReloadPwmFullCycle;

change it to " kPWM_ReloadImmediate", check whether  "Immediate"   take effect, also can compare the difference between two configurations.

BR

Alice

[明省徐]

Hi, Alice_Yang:

    I Test with SDK demo "PWM", default  configuration,change reloadLogic to kPWM_ReloadImmediate.

/* Use kPWM_ReloadImmediate reload */
pwmConfig.reloadLogic = kPWM_ReloadImmediate;

And check  LDMOD is 1.

But when i change pwm duty, the duty is not change Immediate.

My test code  is as follows:(pwm frequent is 10khz)

Spoiler

Config change:
pwmConfig.reloadLogic = kPWM_ReloadImmediate;
/* PWM A & PWM B form a complementary PWM pair */
pwmConfig.pairOperation = kPWM_ComplementaryPwmA;
pwmConfig.enableDebugMode = true;

infinite loop：

while (1U)
{
    /* Delay at least 100 PWM periods. */
    SDK_DelayAtLeastUs((1000000U / APP_DEFAULT_PWM_FREQUENCE) * 100, SDK_DEVICE_MAXIMUM_CPU_CLOCK_FREQUENCY);

    Test_IO_Val_Set(1);

    if(test_AC_duty == 100){
      test_AC_duty = 0;
      PWM_UpdatePwmDutycycle(BOARD_PWM_BASEADDR, kPWM_Module_0, kPWM_PwmA, kPWM_SignedCenterAligned, test_AC_duty);
      PWM_SetPwmLdok(BOARD_PWM_BASEADDR, kPWM_Control_Module_0, true);
    }
    else{
      test_AC_duty = 100;
      PWM_UpdatePwmDutycycle(BOARD_PWM_BASEADDR, kPWM_Module_0, kPWM_PwmA, kPWM_SignedCenterAligned, test_AC_duty);
      PWM_SetPwmLdok(BOARD_PWM_BASEADDR, kPWM_Control_Module_0, true);
    }

    Test_IO_Val_Set(0);

}

[Alice_Yang]

Hello @明省徐 

Could you please send the whole project, thanks.

BR

Alice

[明省徐]

Hi, Alice_Yang:

    this is the project.

[jimmyli]

Hi Alice,

     Per replyed by xu mingsheng,  I can't find another way to fix this problem.

     Can you help to check again ?

     This problem will impact the PWM out from LPC5536, and lead to the project be pending.

     Thanks very much.

[Alice_Yang]

Hello @jimmyli 

What about the result picture on your side? Is the same with 明省徐 ?

BR

Alice

[jimmyli]

Hi Alice,

      Thanks very much.

      I will try again.