Using FTM3 with Internal Oscillator (KV31f512)

p_hedlund — Wed, 10 Apr 2019 15:15:32 GMT

I am using the internal oscillator with the KV31F512 Processor.

Our application is a Brushless DC motor controller. (phase u Hi, low, phase v hi, low and phase w hi and low)

I was given a board design that already existed but was never tested.

All 3 of the lo phases are just on and off, All 3 of the hi phases are gated PWM's

Phase U is PortA13 FTM1-CH1

Phase V is PortE25 FTM0-CH1

Phase W is PortE6 FTM3-CH1

Using the FRDM-kv31f and subbing PortC2 for PortE25 The software runs and i get the expected signals.

Our Target board however does not an external crystal and we must use the internal oscillator.

I have an UART2 working at 115200 without issue.

I have a timer running to control the start/stop of the 3 phases.

PhaseW does not work.

Further testing has found that if i comment out code for Phase U and Phase V, and only have Phase W enabled, I get pulses on Phase U.

Since this worked on the FRDM-KV31F board and not our target I am wondering if there is some interaction i am unaware of when using the internal oscillator.

If you need to I can send code snippets to show what i am doing.

I know the preferred method is to use ONE FTM for a motor but the layout was already done.

Thanks in advance.

Peter Hedlund

Re: Using FTM3 with Internal Oscillator (KV31f512)

p_hedlund — Wed, 10 Apr 2019 18:32:24 GMT

Problem Fixed - When timer was enabled was the issue.

topic Re: Using FTM3 with Internal Oscillator (KV31f512) in Kinetis Microcontrollers

Using FTM3 with Internal Oscillator (KV31f512)

Re: Using FTM3 with Internal Oscillator (KV31f512)