topic Re: FRDM-K64F FTM_CH5 output as PWM using KDS_3.2+KSDK_v2 in Kinetis Software Development Kit

FRDM-K64F FTM_CH5 output as PWM using KDS_3.2+KSDK_v2

nadine — Mon, 09 May 2016 09:20:11 GMT

Hi,

I wrote a program using the FTM timer to configure a PWM clock and associate it

to a specific GPIO.

As described in the Reference Manual (section K64 Signal Multiplexing an PIn Assignments),

I used the GPIO PTA0 multipexed and set to FMT0_CH5 (ALT3).

The program is quite simple and linked to this message (main.c)

In the interrupt function, I made the red led blink. It looks ok, but if I plugged

an oscilloscope to the PTA0 pin, I have no signal output generated.

I probably made something wrong ...

Thanks for your support again

Best regards

Nadine

Original Attachment has been moved to: main.c.zip

DavidS — Mon, 09 May 2016 16:23:46 GMT

Hi Nadine,

I branched this post since one question had been answered correctly.

Attached is your main.c updated to work with KDS_3.2 (Note I think you are using KDS3.0 so please update if you can) + KSDK_v2 for FRDM-K64F.

I have one #define to change the output from PTA0 to PTD5 so that I could debug the code. PTA0 used for debugger interface.

#define OUTPUT_PIN 0

//DES 1=PTD5 (can debug), 0=PTA0 (loose debugger interface)....read notes above main().

Please review my comments by looking for "//DES" comments.

I think the primary issue was setting duty cycle to 100. I made following change:

ftmParam[0].dutyCyclePercent = 50U;

//DES was 100U; 100% duty cycle means output will not change.

Regards,

David

nadine — Tue, 10 May 2016 09:45:51 GMT

Hi David,

Thanks for the answer.

As you suggested, I have used another GPIO.

And, as the GPIO PTD5 is used for the SPI in my design,

I have used PTA2 (FTM0_CH7) and it works fine.

Best Regards

Nadine,