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MSP430FR2311: MSP430FR2311 - buffering an analog signal

George Fleming II
Prodigy 200 points
Part Number: MSP430FR2311
Other Parts Discussed in Thread: MSP430WARE

I am feeding an SMT microphone signal into a bandpass filter; however, the microphone has an output impedance that varies from 0 to 400 ohms that is causing the bpf to not operate correctly. I need to buffer the signal for the analog microphone before feeding it into the bandpass filter. I am aware the MSP430FR2311 has unity gain analog buffers for the ADC blocks. Is there any way to send the analog output from the SMT microphone into a pin, buffer the signal using these unity gain buffers, and output the buffered signal to a different pin on the MCU?

Thank you,

George

  • 0
    Guru 46710 points
    You can find answer by reading user manual (SLAU445), chapter 19: "Smart Analog Combo (SAC)".
  • 0
    TI__Intellectual 2005 points

    Hi George,

    Yes, Configure SAC-L1 for Unity-Gain Buffer Mode.  Send SMT microphone output into OA0+, connected OA0- with OA0O from external, then output the buffered signal from OA0O to filter.

    There is an example code in MSP430Ware showing how to set up the resigter for this application.  

    msp430fr231x_SAC_L1_02.c SAC0, Unity-Gain Buffer Mode

    Regards

    KC

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