Initializing ADC in 28335

Vijay Chand Ganti

I am facing problem using ADC of the 28335 board.I bult a simple model in simulink, to read the value of ADC input into a memory location and store it into a variable.

Now, when i execute the program and with no input to the ADC pin (ADCBIN0 in my case), the value of the corresponding input is not showing zero, but some arbit value. Even the corresponding ADCRESULT register is showing some arbit value.

Can someone please tell me whats the problem and how to intialize the ADC registers from SIMULINK ( if thats the problem of error).

Guess this is a basic "starters" problem and so i am awaiting a reply soon.

Thanks in Advance

Vijay Chand Ganti.

over 15 years ago

0 Lori Heustess over 15 years ago

TI__Guru* 93800 points

Vijay Chand Ganti said:
Now, when i execute the program and with no input to the ADC pin (ADCBIN0 in my case), the value of the corresponding input is not showing zero, but some arbit value. Even the corresponding ADCRESULT register is showing some arbit value.

Vijay,

If there is no voltage applied to the pin then you are converting some unknown voltage on a floating/disconnected pin. Random voltage == random result.

Please also see this post:

http://e2e.ti.com/support/microcontrollers/tms320c2000_32-bit_real-time_mcus/f/171/p/21458/82936.aspx#82936

-Lori

0 Vijay Chand Ganti over 15 years ago in reply to Lori Heustess

Prodigy 80 points

Thanks for your reply Lori.

My ADC conversion is absolutely fine. I am just worried with the "no-input" condition....So this has nothing to do with the ADC intialization right?

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Initializing ADC in 28335