question about 28335 ADC

Hello,

Which TI example that you refer to?

Best regards,

Maria

Hi Tao,

I would like you to download controlSuite and then try this example out:

C:\ti\controlSUITE\device_support\f2833x\v133\DSP2833x_examples_ccsv4\adc_soc

Do inform us with your observation. Also, do read the instructions given at the start of the code.

Regards,

Gautam

i refer to Example_2833xAdcSeqModeTest,

i also tested Example_2833xAdc,and the waveform of INAx output is tested  as

hi, thanks for your reply.

i have tested the C:\ti\controlSUITE\device_support\f2833x\v133\DSP2833x_examples_ccsv4\adc_soc

and the result keeps unchanged.

the output waveform of INAx is as 

sorry! i attach the result pic again

I'm not getting what are you observing on DSO from ADC channel!

Here's the test procedure to check your ADC:

1. Input around 1.5V from a DC power supply to your ADC INA0

2. Observe the ADCRESULT0 while debugging on the watch window.

3. If your value is around 2048 then your ADC is all well.

Do inform what you observe after conducting this test.

Regards,

Gautam

i input 1.5V to INA0 and   ADCRESULT0 is 0xfff0, so is ADCRESULT1 (no input to INA1).

i input 1.5V to INA0 and   ADCRESULT0 is 0xfff0, so is ADCRESULT1 (no input to INA1).

I hope your ADC is not damaged. BTW can you attach the screenshot of your watch window? Enable continuous refresh while taking the  screenshot.

Regards,

Gautam

Hi Tao,

What are you using to drive the input signal to the ADC?

i debugged the same example on another circuit board, it work well, so i think the ADC module of my circuit maybe broken, but i don't know why, i designed the board as official guid, and i am sure i have not input a votage higher than 2V

i uesd a power supply to provide the 1.5v input and use two wires to connect the power supply and the INAX

i debugged the same example on another circuit board, it work well, so i think the ADC module of my circuit maybe broken, but i don't know why, i designed the board as official guid, and i am sure i have not input a votage higher than 2V

If input voltage is not more than 2V and considering the fact that ADC protection circuitry is already implemented as in http://www.ti.com/lit/an/slaa593/slaa593.pdf

then there's no way the ADC should get damaged.

Regards,

Gautam

i have found the error, ADCREFM and ADCREFP are connected in my board. I have seperated them and then it work!

Ahhh.... Great!

Goodluck & Regards,

Gautam