Generating sinusoidal waves with MPC5554EVB

[ricardofranca]

Hello,

I have just started using a MPC5554EVB (with CodeWarrior) and I am running small programs to understand a bit about its features.

I would like to know if I can generate sinusoidal, analog waves in the processor outputs - I think I could understand the examples provided in AN2865 that make use of OPWM and OPWFM eMIOS functions to generate square waves with variable pulse width and frequency, and I would like to know if there is any similar mechanism that may generate something like a sine wave.

Do not hesitate to correct my terminology if it is not adequate!

Thanks in advance,

Ricardo

[PetrS]

Hi,

The MPC5554 cannot generate analog signal directly on the output pin. You will need some external circuitry.

The theory is quite simple. With the help of eMIOS you will generate PWM signal with certain period, that’s duty cycle will be modulated by desired sine frequency, i.e. changed duty cycle fast enough from sine lookup table for example.

This will generate sine modulated PWM signal on digital output. With the help of analog low pass filter you can get analog sine wave signal.

You can find a lot of guides/solutions on the web, just search for “PWM sine generator” etc. 

BTW; the MPC5643L, MPC5744P contain a SWG (Sine Wave Generator) module, which generates the sine output directly.

BR, Petr

[ricardofranca]

Hi Petr,

Thanks for your answer!

Best regards,

Ricardo