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PCM5242EVM - Where do I start?

user1625740
Prodigy 30 points
Other Parts Discussed in Thread: PCM5242, SRC4392

I received a PCM5242EVM today; it arrived with NO documentation. Going to the TI website for the EVM, I find the Technical Documents tab does not respond. I found only a quick-start guide for a board with a headphone amp. My EVM has no HP amp, only XLR outputs.

The board has what appears to be a USB micro B connector. Is that correct? Had I known one was required (there is no mention on the TI website, nor is one supplied) it could have saved me a week.

The board also has Toslink and SPDIF connectors. The Toslink is at least marked as an input, but the SPDIF is not marked. One assumes it is an input because there is a jumper below which allows MCLK to come from either SPDIF or USB. Will the board run standalone using these other inputs? or does it have to be configured using a PC? How about playing iTunes from a Mac?

Eventually I want to feed the DAC I2S signals, so thorough technical documentation would be appreciated.

  • 0
    TI__Mastermind 27880 points
    Hi,

    The PCM5242EVM and the High Fidelity Audio Headphone Playback Reference Design for Portable and Smartphone Applications are very similar except that one has an output amplifier and headphone out. You can use the quick start guide here: www.ti.com/.../tidu640.pdf for both the EVM and the TI design.

    The software for the PCM5242 is available to request here: www.ti.com/.../purepathconsole. However, there should be a software link below in a software section. This will be updated.

    Yes this is a micro USB B connector. If you have a recent cell phone you can use the same USB cable.

    The SPDIF and Optical ports are both inputs since the PCM5242 is a DAC, which can only take in digital data. The SPDIF and optical ports are controlled by the SRC4392, which must be programmed by our PurePath Console software through USB (or any host controller with I2C).

    If you were to input I2S into the PSIA bypass headers, you could configure the PCM5242 into hardware contolled mode and use it without the PPC software.

    We will update the PCM5242EVM page with more information.

    Justin
  • 0 in reply to Justin Bohr
    Prodigy 30 points
    Thank you, Justin. Having full technical information on the TI website would have been helpful. I've been used to seeing EVM technical manuals complete with schematic and pcb layout. Will this be provided for the 5242 evm? At the least, an explanation of how to set up all the operating modes/jumpers on the board would be most helpful.

    I understand the PCM5242 also has an output mode to take advantage of the internal DSP when using it, for example, as a loudspeaker crossover. That's why I asked about the SPDIF jack.

    Why do the Toslink and SPDIF inputs require the SRC? The DAC data sheet says it generates its own MCLK internally. Couldn't it do this for all inputs?

    Regards,
    Rene'
  • 0 in reply to Justin Bohr
    Prodigy 30 points

    Hi Justin,

    Any news on the PCM5242EVM tech docs update?

    Rene'

  • 0 in reply to user1625740
    TI__Mastermind 27880 points
    Hi Rene

    Since these documents need to be edited and passed through our technical docuement team for approval, this will take some time. As stated before you can use the documents for the TI reference design, as the only difference between the boards is the output amplifier. The schematic (minus the output amplifier), software and quick start guide will be the same. These are found here: www.ti.com/.../TIDA-00385 Documents

    The SRC part is required because the DAC does not have the ability to take in a SPDIF signal, which is an audio clock and the data in a single signal. You can input an I2S signal directly to a DAC, but SPDIF needs to be converted to I2S first.

    The PCM5242 can output a digital I2S signal but on the EVM and reference design this is not routed to the Otical or coax ports. This DOUT pin is the GPIO2 pin that is routed to a header.

    Justin