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CCS/MSP430FR5994: BOOSTXL-AUDIO_FFT: connecting the audio through wires does not work

Part Number: MSP430FR5994
Other Parts Discussed in Thread: BOOSTXL-AUDIO, , TS3A44159

Tool/software: Code Composer Studio

Hi,

I am playing BOOSTXL-AUDIO_430BOOST-SHARPLCD_FFT_FIR_LEA_MSP430FR5994. I have a 5994 launchpad and the BOOSTXL-AUDIO board. I do not need the LCD so I deleted all the LCD related code and it works perfectly if I stack the audio board on/below the 5994 launchpad. Because for my project I only need that audio sensor from the BOOSTXL-AUDIO board, I tried to connect the launchpad and the BOOSTXL-AUDIO board by wires. For example, the project is using P3.1 for audio-output, P4.1 for audio power and also GND. I tried to connect those three pins between the launchpad and the BOOSTXL-AUDIO board through wires(without stacking them together). Then the FFT result does not make sense. The FFT can not tell the frequency of the sound source. If I stack the two boards together, the FFT works well in telling the frequency of the sound source. 

Based on my current understanding, if only the audio senor is used for the project, connecting those three wires should work as well as stacking the two boards together, right?

Thanks,

Yubo

  • Based on the schematics in the Boost UG (SLAU670A) and the:LP UG (SLAU678A):

    1) P3.1 is on J3.24, which on the Boost appears to be Not Connected. MIC_OUT_ALT is on J3.26 (P3.3 on the Launchpad).

    2) MIC_OUT_ALT and MIC_PWR_ALT (J4.31/P4.1) are used by moving (re-soldering) 0-ohm resistors. If you haven't done this you're using MIC_OUT_PRI (J1.6/P1.3) and MIC_PWR_PRI (J1.5/P6.2)  

    3) MIC_RAW comes in through an analog switch (TS3A44159) which I suspect doesn't pass anything if 3V3 (J1.1) isn't connected. Even if it does, the "normally closed" position uses the output from the headphone mic. There's a pullup, but once you connect 3V3 it will probably do the right thing.

    Summary: (1) Connect to one of the MIC_OUT_xxx pins (2) Use the appropriate (PRI vs ALT) pins for OUT and PWR based on the 0-ohm resistor configuration (3) Connect 3V3.

  • Hi Yubo,

    Please let me know if you continue to have issues after looking at Bruce's suggestions.

    Thanks,

    Mitch

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