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PCM1808EVM: Distorted signal

EliC
Prodigy 40 points
Part Number: PCM1808EVM
Other Parts Discussed in Thread: PCM1808

Hi,

I'm testing the PCM1808EVM evaluation board. I have to use the device as a slave device so I set up the board in slave mode, put MD0 and MD1 to GND.
I generate a SCKI clock signal using a PWM signal from the microcontroller (ESP32S3) at 8 Mhz so the audio sample rate is 31250 Hz. The clock rise and fall times seems within spec...
When recording a 1 kHz sine wave, the digitalized signal is distorted heavily.

Could someone look at my clock measurements here and suggest any possible solutions/options to make this device work in slave mode?

Thanks!

CH1 (yellow) = SCKI
CH2 (blue) = BCK
CH3 (magenta) = LRCK

  • 0
    TI__Expert 5665 points

    Hey Elic,

    Thank you for bringing this to our attention. Could you please share the other jumper configurations you have on the evm? a schematic of that would be helpful. 

    Regards,

    Ore.

  • 0 in reply to Ore Ogundana
    Prodigy 40 points

    Hi Ore,

    thanks for your reply.
    The evaluation board connection headers are connected to the ESP32S3 devkit-C board using jumper cables. I added the connections and jumpers of the evaluation board on the schematic in green. The data format is set to I2S.

    Jumpers on the EVM:
    J5: SLAVE
    J6: GND
    J7: GND
    J8: GND

    Kind regards,
    Eli

  • 0 in reply to EliC
    TI__Expert 5665 points

    Hey Eli,

    Thanks for providing the complete schematic. I would get back to you with a response next next week.

    Regards, 

    Ore. 

  • 0 in reply to EliC
    TI__Expert 5665 points

    Hello Eli,

    Your schematic looks fine and you have only provided clock signals that look fine as well, I don't see the SDOUT signal, could you please provide that? Try to provide screenshots for both left-justified mode and i2s mode for better visuals. Use this: 

    pic

    I advice you make sure the BCLK and FSYNC are leaving your host device and are directed into the pcm1808 as a slave mode device. 

    Regards, 

    Ore. 

  • 0 in reply to Ore Ogundana
    Prodigy 40 points

    Thanks reaching out. I had some noise on the GND that made the clock jitter too much. The data seems correct now.