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CCS/CC430F6137: ADC output reading is not constant and varies

es
Intellectual 370 points
Part Number: CC430F6137
Other Parts Discussed in Thread: MSP-FET

Tool/software: Code Composer Studio

Sir, I am using cc430f6137 ic. my doubt is,

1. what is maximum input voltage apply to adc input channels.

2.the current sensor which i am using is very sensitive, the output rating will be (13.33mV) for each amperes.

3.the ADC output value from the MCU is varies between 10 to 20mV and above. so I can't capture accurate value of sensor.

4.I am using this (cc430x613x_adc12_07) sample adc code and this value is monitor through uart communication. I am using single sensor only.

5.Do you have any other suggestion to use alternate adc code (or) i can use same adc code to achieve accuracy.

6.what are the possibilities and options should be done in my code(cc430x613x_adc12_07).

Please send soon,

Regards by,

Siva.E

  • 0
    TI__Mastermind 49692 points

    Sivanathi said:
    1. what is maximum input voltage apply to adc input channels.

    Have you looked for this in the datasheet? You can find it in Section 5.35.

    Sivanathi said:
    2.the current sensor which i am using is very sensitive, the output rating will be (13.33mV) for each amperes.

    Ok, but you don't say how many amps you're measuring. What's the current sensor?

    Sivanathi said:
    3.the ADC output value from the MCU is varies between 10 to 20mV and above. so I can't capture accurate value of sensor.

    Based on your input voltage, does your ADC result match what you're calculating using the conversion formula in Section 20.2.1 in the User's Guide? Please check this. You'll need to know what reference voltage you're using.

    I'm assuming you're using a custom board. Please go through the datasheet and make sure you're using the correct passives on the pins (AVCC, DVCC, VCORE, VREF, etc.). Figure 20-12 in the User's Guide illustrates some of these connections.

    Sivanathi said:
    4.I am using this (cc430x613x_adc12_07) sample adc code and this value is monitor through uart communication. I am using single sensor only.

    Make sure your communication isn't affecting your ADC sampling. You may want to use an array in your code (you can search the forum for how to do this), run for a certain number of samples while debugging, and then read what's in the array using the debug feature of CCS with the MSP-FET.

    Regards,

    James