CC2340R5: how to use one LPGT to send 3 PWM output on different different channel

Frank(EP) Liu

Expert 4800 points

Part Number: CC2340R5
Other Parts Discussed in Thread: SYSCONFIG

Tool/software:

Hi Expert,

want to confirm below due to it's not in example code.

I want to have 3 pwm output with different duty setting. I only want to use 3 channel in LGPT3.

the sysconfig setting is as below.

i can use below to enable 3 channel, right?

PWMTimerLPF3_Object *object = pwm1->object;

object->chNumber = 0;
pwm1 = PWM_open(CONFIG_PWM_0, &params);
if (pwm1 == NULL)
{
/* CONFIG_PWM_0 did not open */
while (1) {}
}

object->chNumber = 1;
pwm11 = PWM_open(CONFIG_PWM_0, &params);
if (pwm11 == NULL)
{
/* CONFIG_PWM_0 did not open */
while (1) {}
}
object->chNumber = 2;
pwm12 = PWM_open(CONFIG_PWM_0, &params);
if (pwm12 == NULL)
{
/* CONFIG_PWM_0 did not open */
while (1) {}
}
object->chNumber = 0;
PWM_start(pwm1);
object->chNumber = 1;
PWM_start(pwm11);

object->chNumber = 2;
PWM_start(pwm12);

object->chNumber = 0;
PWM_setDuty(pwm1, duty);
object->chNumber = 1;
PWM_setDuty(pwm11, duty);
object->chNumber = 2;
PWM_setDuty(pwm12, duty);

But I cannot get it work. So, I think that I may misunderstand something.

BR,

frank

over 1 year ago

0 Ryan Brown1 over 1 year ago

TI__Guru**** 217237 points

Hi Frank,

Please be aware of this previous E2E thread.

Regardless of an object's chNumber, PWMTimerLPF3_open -> PWMTimerLPF3_getPwmChannelNo will select the first valid channelConfig[x].pin (from the ti_drivers_config.c generated by SysConfig) as its pwmChannelNo. Hence your channel 0 (first) may be functional, but channels 1 and 2 will not be.

/*
 *  ======== PWMTimerLPF3_getPwmChannelNo ========
 */
static LGPTimerLPF3_ChannelNo PWMTimerLPF3_getPwmChannelNo(uint_least8_t index)
{
    LGPTimerLPF3_HWAttrs const *hwAttrs;
    LGPTimerLPF3_Handle handle;
    LGPTimerLPF3_ChannelNo channelNo;

    handle  = (LGPTimerLPF3_Handle)&LGPTimerLPF3_config[index];
    hwAttrs = handle->hwAttrs;

    /* Find the channel that has been connected to a pin.
     * It's assumed that only one of the ordinary channels have been
     * muxed to a pin.
     */
    if (hwAttrs->channelConfig[0].pin != GPIO_INVALID_INDEX)
    {
        channelNo = LGPTimerLPF3_CH_NO_0;
    }
    else if (hwAttrs->channelConfig[1].pin != GPIO_INVALID_INDEX)
    {
        channelNo = LGPTimerLPF3_CH_NO_1;
    }
    else
    {
        channelNo = LGPTimerLPF3_CH_NO_2;
    }

    return channelNo;
}

You will need to copy the source\ti\drivers\pwm\PWMTimerLPF3.c file to your workspace and modify accordingly to meet your specific application needs.

Regards,
Ryan

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CC2340R5: how to use one LPGT to send 3 PWM output on different different channel