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ADCREFIN of TMS320F28335

Tuan Tran
Prodigy 20 points

Other Parts Discussed in Thread: TMS320F28335

Hi all,

I am using TMS320F28335

Can i apply 3V to ADCREFIN pin, if yes, please show me the way to configure the hardware to achieve that? because when i read the ADC ref guide of tms320f28335, there are

just 3 choices for ADCREFIN 2.048V, 1.5V and 1.024V.

  • 0
    TI__Guru* 82820 points

    Tuan,

    The options listed are the only ones supported.  For this ADC these voltages on ADCREFIN do not re-scale the ADC input, rather provide an alternative to the internal referenece to get better than the 50ppm/deg C temp movement it provides.  Range is always 0 - 3V with any reference selection.

    Best,

    Matthew

  • 0 in reply to MatthewPate
    Prodigy 20 points

    MatthewPate, thank for answering my question.

    "For this ADC these voltages on ADCREFIN do not re-scale the ADC input", so if i choose 2.048V for ADCREF, can i still achieve these equation

    digital value =0  when input <= 0

    digital value = 4096*(input - ADCLO)/3    when 0 < input < 3V

    digital value = 4095 when input >= 3


    OR:

    digital value =0  when input <= 0

    digital value = 4096*(input - ADCLO)/2.048    when 0 < input < 2.048V

    digital value = 4095 when input >= 2.048