TMS320F28379D: TMS320F28379D ADC EPWM example

Thank you.

And Can I ask one more thing.

I want to see the ADC result in the CCS.

So I set the value like below.

and when I saw the value, it looks weird.

There is big spike as you can see.

The input value is 60Hz 1Vpp voltage.

Can you give me a some sugeestion?

and also when I looked at the butter the number is not the exact number as what I input.

I think I should some transformation.

What equation should I need to use?

Best regards,

Mingi Oh

Thank you for the information.

But I am still struggling with this issue

The below graph is my adc buffer output.

It does not look like sine wave form.

I just connected 1Vpp to J30.

Did I miss something?

Also, I have some additional questions about this ADC.

1. When I connected PinJ3 GND to 1Vpp input ground and measure voltage in oscilloscope, the waveform is not sinewave anymore.

What is the reason for it?

I do not have to connect GND in the launch pad from externally when I use ADC module?

2. Vreflo and VrefHI

You explained if I want to transfer to the real value, I need to calculate the value using Vreflo and VrefHi.

And when I studied about it, it lookes likes external value.

Can I conned 5V or 3.3V for VrefHi and GND for the VrefLo in the launchpad?

Thank you for always your help.

Best regards,

Mingi Oh

Mingi Oh said:

I just connected 1Vpp to J30.

Did I miss something?

I recommend that you first try to sample DC voltage levels to gain confidence in the ADC behavior before moving on to AC signals.

Mingi Oh said:

1. When I connected PinJ3 GND to 1Vpp input ground and measure voltage in oscilloscope, the waveform is not sinewave anymore.

What is the reason for it?

I do not have enough information to provide an explanation for what is going on in your system. It would make sense to correct the observable input signal before trying to interpret the ADC conversions.

Mingi Oh said:

I do not have to connect GND in the launch pad from externally when I use ADC module?

A ground reference is definitely required for all input signals.

Mingi Oh said:

2. Vreflo and VrefHI

You explained if I want to transfer to the real value, I need to calculate the value using Vreflo and VrefHi.

And when I studied about it, it lookes likes external value.

Correct, the reference voltages are external to the F28379D. TI EVMs like LAUNCHXL-F28379D and TMDSCNCD28379D include on-board references already. You can find additional details in the relevant schematics.

Mingi Oh said:

Can I conned 5V or 3.3V for VrefHi and GND for the VrefLo in the launchpad?

Any reference voltage level that satisfies the datasheet requirements may be used:

The TRM provides guidelines for Designing an External Reference Circuit.

Correct, the reference voltages are external to the F28379D. TI EVMs like LAUNCHXL-F28379D and TMDSCNCD28379D include on-board references already. You can find additional details in the relevant schematics.

 I can find the Vreflo(PIn33) and Vrefhi(Pin37) of the F28379D.

However, I don't know how I can access the Pin in the lauchpad.

When I looked at the datasheet of the launchpad, there are not connected the Vreflo and Vrefhi..

Could you please let me know how to connect those pins using Launchpad?

Best regards,

Mingi Oh

Thank you for the reply.

So I don't need to connect Vreflo and Vrefhi.

Therefore, when I run the explample2, I need only to connect analog input to J30, right?

I don't need any other connection, right?

Best regards,

Mingi Oh

Yes, an input signal and a common ground reference should suffice.