topic Re: FRDM KL25Z PWMTiming configutation problem in Kinetis Microcontrollers

FRDM KL25Z PWMTiming configutation problem

kesaradecosta — Thu, 29 Nov 2012 23:31:34 GMT

I need to use the freedom board to run a small robot project

I need 2 PWM channels to run 2 motors
Need 2 to 3 channels to send 10 us trigger pulse for Ultrasonic sensors
Needs 3 to 5 channels to capture the return pulses from Ultrasonic sensors

I am having trouble setting up the timer module TPM2 on the code warrier 10.3 beta to configure to have 2 PWM channels with 4kHz to control the duty cycle of the motors ( L293D )

Can anyone help me in setting up the timer.

Your help is much appreciated.

Re: FRDM KL25Z PWMTiming configutation problem

adriansc — Tue, 11 Dec 2012 17:14:11 GMT

Hi,

If you are using different channels from the same TPM and you want 4 kHz in both, use the same Timer Unit in channel 0 and channel 1.

The TimerUnit component uses different channel for your configuration, you can see this in the image.

This configure the same frequency of 4kHz in channel 0 and channel 1 but you can set the duty cycle for each channel.

Hope this helps.

Re: FRDM KL25Z PWMTiming configutation problem

kesaradecosta — Wed, 12 Dec 2012 01:04:41 GMT

Hi Adrian,

I have got the PWM running and posted in the forum https://community.freescale.com/thread/300691 and thanks for your help.

Please help me on configuring and coding the Ultrasonic sensor

I tried to use 1 channel of PWM to send trigger pulse and capture the eco signal on TPM0_CNT with rising edge and using coding shown in the help on the component.

Please help me on configuring and coding to read the range

Thanks,

Kesara De Costa

Re: FRDM KL25Z PWMTiming configutation problem

kesaradecosta — Wed, 12 Dec 2012 05:14:48 GMT

Hi Adrian,

Finally managed to configure the timers to get the range reading.

code is

void GetRange (void){

PWM1_SetDutyUS(PWM1Ptr, 35u);

PWM1_Enable(PWM1Ptr);

Index = 0;

Error = TU1_ResetCounter(MyTU1Ptr); /* Start new measuring */

Overflow = FALSE;

Done = FALSE;

do {} while (!Done && !Overflow) ; /* Wait for end of measurements or time-out */

if (Overflow) {

/* Time out. Period of measured signal is too long */

Bit2_PutVal(Bit2Ptr, 0);

}

else {

/* TU1_CNT_INP_FREQ_R_0 is a counter input frequency in Hz - see header file */

Period = (Ticks[1] - Ticks[0]) / TU1_CNT_INP_FREQ_R_0; /* Period of the signal in seconds */

}

PWM1_Disable(PWM1Ptr);

}

int j=0;

for(;;){

GetRange();

Range = Period * 34000/5;

for(j= 1; j<= 10000; j++){

Bit1_PutVal (Bit1Ptr,Range< 10);

}

On the events

void TU1_OnChannel0(LDD_TUserData *UserDataPtr)

{

/* Write your code here ... */

Error = TU1_GetCaptureValue(MyTU1Ptr,CHANNEL,&Ticks[Index]); /* Store captured value to array Ticks */

Index++;

if (Index >= NUMBER_OF_MEASUREMENTS) {

Done = TRUE;

}

But the measurement is not 100% accurate.

Kesara De Costa