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MSP430FR5969: i2S processor selection - Need 4 stereo i2S input

Chris from Pinterec
Expert 1560 points
Part Number: MSP430FR5969


Hello,

I am looking for a processor that can receive 8 i2S channels and convert each channel into an .mp3 file.   So I need a multi imput i2S processor.   I am looking at the MSP430FR5969  because it has 8 SPI channels.   I am not sure if this is going to help me.

This is my first project with I2S so I am not sure which processor to use.

Any opinions would be great.

Chris

  • 0
    Guru 34773 points
    There is "Interfacing an I2S Device to an MSP430 Device" (www.ti.com/lit/an/slaa449a/slaa449a.pdf) but there is no enough horse power in MSP430 tree to handle streaming I2S to mp3 conversion.
  • 0 in reply to zrno soli
    Expert 1560 points
    Thanks a lot. This is very helpful. At least now I can see how to use SPI for i2S application. The input channel has a bandwidth of 25kHz so according to nyquest I need at least 50kHz per word (symbol). With a 24bit word the rate the clock rate will need to be at least 1.2 MHz per channel. So a 10MHz processor should be fine.

    The MSP430 can clock at a maximum of 24MHz. In theory....this should work. I first thought I would need an arm, such as the ARM Cortex-A8 which is on the beaglebone black. It runs at 750Mhz. I can use this with linux so it might be better.....But the MSP430 has better power management.

    Why would you say the MSP430 would not do the trick?

    Thanks,

    Chris
  • 0 in reply to Chris from Pinterec
    Guru 46710 points

    Chris from Pinterec said:
    The input channel has a bandwidth of 25kHz so according to nyquest I need at least 50kHz per word (symbol). With a 24bit word the rate the clock rate will need to be at least 1.2 MHz per channel. So a 10MHz processor should be fine.

    I would say that this is very strange way to assess computing resources for MP3 encoder. You really shall double-check your approach, because in my opinion you calculated just resources needed to receive single I2S bitstream, without doing any meaningful conversion of it.

    Here is brief info that states that 16KSps mono MP3 audio compressor takes 20MIPS out of DSP processor (which msp430 is not).

    You easily can drop your idea about picking msp430 because "it is low power". MP3 audio encoding requires lot of computing resources which you shall not do on microcontroller designed for wristwatch.

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