TMDSDOCK28379D: C2000™ microcontrollers forum

Fuat Kucuk

Part Number: TMDSDOCK28379D

Hello everyone.

I have been trying to make voltage signal measurement from Matlab/simulink through an ADC of F28379D. It works fine with DC voltage measurement, for example when I change the DC voltage from 1 to 3 V. Please see the following figure.

However, when I would like to measure an AC signal with amplitude of 3V and an offset of 1.5V, it just measures a kind of noise as seen in the following, even at low frequency (100Hz).

I have used voltage follower (buffer) to make an impedance matching between the microprocessor ADC and source but nothing changed. Is there any way of fixing this problem?

Here are the setting for hardware and ADC.

Thank you in advance.

over 4 years ago

0 venkatesh chilapur over 4 years ago

Mastermind 6460 points

Hi,

Check this out!

0 Fuat Kucuk over 4 years ago in reply to venkatesh chilapur

Prodigy 50 points

Dear Venkatesh,

Thank you for your interest. My situation looks different than that. I increased the baudrate of the COM port to maximum and still I got weird signal as shown before. I can measure DC voltage but not variable voltage. I believe it is somehow related to impedance but I already considered that before.

The COM settings are as follows.

0 venkatesh chilapur over 4 years ago in reply to Fuat Kucuk

Mastermind 6460 points

Hi,

Please consider contacting MathWorks support, they usually have WebEx with customers to help sort out these issues.

0 Chandima Jayawardana over 4 years ago in reply to venkatesh chilapur

Prodigy 70 points

HI,

I'll try, thank you.

chandima

0 Fuat Kucuk over 4 years ago in reply to venkatesh chilapur

Prodigy 50 points

Hi Venkatesh,

Now I understood that I can receive ac signals as well but with very low resolution. I lose the signal even in the case of measuring 20 Hz signal. I have learned that increasing SCI-A baudrate (for example 12e6) can help to increase accuracy. However, it did not work for my case. I have checked XDS100 serial port settings from device manager of the computer, the maximum bitpersecond is only 921600 which is far low from the SCI-A baudrate. I cannot input my desired value there and can only select the decided values from pop-up menu.

Is there anything I miss in the settings?

Thank you.

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