topic Re: KL03 DAC output pin for signal generation in Kinetis Microcontrollers

KL03 DAC output pin for signal generation

raff5184 — Thu, 19 Apr 2018 17:39:29 GMT

Hi,

I have a very basic question. I want to generate a signal with the FRDM-KL03 board and give this generated analog waveform say to some external circuit.

I am using KDS software and following the ADC uTasker guide (page 12).

Now, the Kinetis SDK Application User Guide says that: "Normally, the DAC0_OUT is internally connected to the ADC0_SE23 (DAC0_OUT is a source of ADC0_SE23),".

So, is the output of the DAC going in input to the ADC?

And if I want to "see" the generated signal, to which jumper on the FRDM-KL03 board should I connect? From the KL03 Sub-family manual (table page 99) it seems to be the J4-PTA9? But I am not sure. I mean I tried but I could not see the waveform

Thank you

Re: KL03 DAC output pin for signal generation

mjbcswitzerland — Thu, 19 Apr 2018 21:35:39 GMT

Hi

The KL03 has a 6 bit DAC in its comparator module and its output is not available on an external pin:

There is no 12 bit DAC as many other parts have which can be used for such functions.

However, what you can do is use a PWM output with an RC filter to generate an analogue output signal or waveform.

Regards

Mark

uTasker developer and supporter (+5'000 hours experience on +60 Kinetis derivatives in +80 product developments)
Kinetis: http://www.utasker.com/kinetis.html

Re: KL03 DAC output pin for signal generation

raff5184 — Fri, 20 Apr 2018 22:00:46 GMT

Thank you Mark,

also would it be possible to do something like that with the GPIO?
Basically I only need to generate a periodic square wave at very low frequencies, not even a sinusoid.

Thank you

Re: KL03 DAC output pin for signal generation

mjbcswitzerland — Mon, 23 Apr 2018 01:01:55 GMT

You can generate square wave outputs (or PWM) with the TPM.
If you prefer to do it with timer interrupts toggling an GPIO output you can do it from the SYSTICK, TPM, PIT etc.

Regards

Mark

uTasker developer and supporter (+5'000 hours experience on +60 Kinetis derivatives in +80 product developments)
Kinetis: http://www.utasker.com/kinetis.html