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PCM1774: Is it possible for the user to operate without setting the register?

Part Number: PCM1774
Other Parts Discussed in Thread: PCM1771, PCM5102A


This time, there is Customer who has evaluated PCM1774 as an alternative to Asahi Kasei AK4352.
The AK4352 communicates with the microcomputer by using the attached 0: 16bit LSB Justified as an audio interface,
and the customer said that serial communication did not require register settings.

I found a description similar to AK's 16bit LSB Justified in the Description of the PCM1774 data sheet.

datasheet page1,DESCRIPTION
The PCM1774 supports right-justified, left-justified, I2S,
and DSP formats, providing easy interfacing to audio
DSP and decoder/encoder chips.

Is it possible for the user to operate without setting the register, like the AK4352?
Or do users always need to set registers?

Best regards,

  • Hi DDdoor,

    The PCM1774 starts with the standard I2S as the default value.  You are not required to configure the device at all if you are using all of the default values.  If your operation is different than the defaults, then you must configure the device.  You could also consider using a device that is hardware controlled, like the PCM1771.



  • Hello Paul,

    Thank you for your reply.

    The PCM1774 is in I2S mode by default, and you said you didn't need any special settings, but I couldn't read it that way, as noted below.

    ・datasheet page12,
    Power-On Reset and System Reset

    Internal circuits are cleared to default status,
    then all analog and digital outputs have no signal.

    Set Register data after turning all power supplies on.

    In addition, register 72 (PMXL, PMXR), register 73 (PBIS, PDAR,
    PDAL, PHPR, PHPL) and register 90 (PCOM) have a default value of 0.
    This is the power down state.
    For this reason, I thought it was necessary to set registers so that they could be used.

    Are these modules powered up by default in I2S mode?

    Best regards,

  • Hi DDdoor,

    You are correct, these are in power-down mode by default.  This will mean that you will need to write to the device to get any real functionality.  

    I recommend you evaluate the PCM1771 if you require a hardware configuration only.  Or you could use a discrete DAC and headphone amp.  For example, you could look at the PCM5102A and pair it with an appropriate headphone amplifier, like TPA6138.