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PCM1808: PCM1808 not producing any signal as master

Philippe Florent
Prodigy 30 points

Part Number: PCM1808

Hello,

I bought this board on amazon : https://www.amazon.co.uk/gp/product/B082MXRC4S/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

I have hooked up the 5V/3V/GND

I also set the MODE0 & MODE1 to 5V, setting FMT to GND

but no signal is produced; I was expecting to see BCK LRC OUT to produce I2S data

does the ship needs initialization of some sort ?

can't find anything in the datasheet

thanks for the time you'll spend answering me

  • 0
    TI__Mastermind 23050 points

    Hi Philippe,

    What SCKI are you providing to the chip? Based on your configuration of master mode 256*fs, if you want to operate at 48kHz sample rate then you need to provide and SCKI of 12.288MHz.

    Best,

    Zak

  • 0 in reply to Zak Kaye
    Prodigy 30 points

    but this makes no sens, what's the point of being the master then ?

    I want to use the chip as a master so I avoid jitter on the clock line from the MCU, to avoid frame drops

    I encountered that issue and someone on another forum suggested to do so

  • 0 in reply to Philippe Florent
    TI__Mastermind 23050 points

    Hi Philippe,

    One device on the bus has to be the master. All that means is that the device will generate BCK and LRCK. You still have to provide a reference clock from which BCK and LRCK can be generated though. It is not common for ADCs, DACs, or CODECs to provide an entire clock generation tree. Some devices include PLLs so they can generate the required clocks over a wider range of reference clocks, but the PCM1808 does not have a PLL so you will need to provide a high quality SCKI. This could be a crystal reference like we use on our EVM if your MCU cannot generate a reliable clock.

    Best,

    Zak

  • 0 in reply to Zak Kaye
    Prodigy 30 points

    ok thanks, I'll check this out