Duty Cycle Selection in PWM channels

[marceli1]

Hi,

I need use one timer with four channels operating on the same frequency, however each channels I need set duty cycle independently out of other channels. Is it possible or I need find micro with four timers?

[mjbcswitzerland]

Hi

Each timer has a single frequency but each of its channels can generate a different duty cycle at this frequency.
See http://www.utasker.com/docs/uTasker/uTaskerHWTimers.PDF (chapter 5 and appendix - page 20) for more details.

Regards

Mark

[marceli1]

Hi Mark,

I am using MKL25Z timer and PE approach. I am able create PWM2 for next channel with the same timer TU1.

 I am not sure when changing duty cycle using:

LDD_TError PWM2_SetDutyMS(LDD_TDeviceData *DeviceDataPtr, uint16_t Time){..}

calling at OnEnd event I will change for only PWM2 set channel.

[Robin_Shen · Accepted solution]

Hi Marceli,

When you create several PWM_LDD with same timer TU1, PWMx_SetDutyMS will only update the duty of selected channelx.

Best Regards,

Robin

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[marceli1]

Hi Robin,

thank you. To avoid output noise I need change duty cycle in the event OnEnd period and this will be separate for each channel done. Problem can be I will get six channels interrupts at the same time on the end of the same period. Will I lost some of interrupts or I need to setup priorities for them and how? 

Kind Regards,

Marceli

[Robin_Shen]

These six channels share the same overflow interrupt.

Best Regards,

Robin

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[marceli1]

Hi Robin,

PE is not allowing me to change initially period timer TU1 while is linked with PWM six channels. It is even Counter restart is in "On-match" mode. Can I make own method to change period for all channels in timer TU1?  

#include "TPM_PDD.h"

LDD_TError TU1_SetPeriodTicks(LDD_TDeviceData *DeviceDataPtr, uint16_t Ticks)
{
  (void)DeviceDataPtr;                 /* Parameter is not used, suppress unused argument warning */
  /* Parameter test - this test can be disabled by setting the "Ignore range checking"
     property to the "yes" value in the "Configuration inspector" */
  if ((Ticks > 65535U) || (Ticks == 1U)) { /* Is the given value out of range? */
    return ERR_PARAM_TICKS;            /* If yes then error */
  }
  TPM_PDD_WriteModuloReg(TPM0_BASE_PTR, (uint16_t)(--Ticks));
  return ERR_OK;                       /* OK */
}

Regards,

Marceli

[marceli1]

Hi Robin,

Thank you, this explains process order very well. Only need to pass channel's duty cycle value at OnEnd channel event.

Regards,

Marceli