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First tas1020b usage

sinosoidal
Prodigy 120 points

Hi,

I have prepared a setup with the tas1020b but i cant get it recognized in the pc.

I was expecting to see it in DFU mode in order to download the firmware example to it.

I have followed the datasheet as reference and i have reviewed several times all the connections.

What can be wrong? What should be my guidlines for debugging this problem?

Thanks,

With my best regards,

Nuno

  • 0
    TI__Expert 4160 points

    Nuno,

    If the TAS1020B comes up and does not find an EEPROM, it reports a StandardConfigurationDescriptor.MaxPower of 125, or 250mA.  Possibly your host cannot provide that amount of power, so enumeration fails.  Can you attach the TAS1020B via a powered hub and see if enumeration passes in that case?

    If that is not the problem, can you capture the USB bus traffic as the TAS1020B is connected to the USB?

    Regards,

    Frank

  • 0 in reply to Frank Minich
    Prodigy 120 points

    Hi Frank,

    Thanks for the reply.

    It happens that the host not even tells me that the enumeration failed... I dont understand. I have doubled checked every connection several times... 

    Nuno

  • 0 in reply to sinosoidal
    TI__Expert 4160 points

    Nuno,

    The host doesn't explicitly tell you that the enumeration failed in this case.

    I think that when the host figures out that there's not enough power to honor the TAS1020B's request, it simply disables the port on the hub to which the TAS1020B is connected.

    Do you have a USB protocol analyzer which can be used to collect USB bus traffic during the connection?

    Have you compared your schematic to that of the TAS1020BEVM?  I'll try to attach it: 7002.TAS1020EVMR2Schematic.pdf.

    Regards,

    Frank

  • 0 in reply to Frank Minich
    Prodigy 120 points

    Hi Frank,

    Its not normal to have a 250mA request? As I understand the maximum a port can deliver is 500 mA.

    However I'll try to get an hub and a traffic analyzer and do the thing again. 

    In the mean while I have tried connecting it to the usb port on an apple usb mini keyboard (which is the only hub i have at the moment) and nothing...

     

    I'll keep you updated!

     

    Thank you very much for you support! It is hard to get answer in this forum.

    Nuno

  • 0 in reply to sinosoidal
    TI__Expert 4160 points

    Nuno,

    You don't indicate whether-or-not you compared your schematic to that of the TAS1020BEVM.

    As to the ROM requesting 250mA, one of our other customers has indicated that this can cause connection failure, and I've noticed a difference in behavior depending upon whether the EVM is connected to a particular laptop's internal USB port or the laptop docking station's USB port.

    As to getting support on this forum, I suggest that you include in your posts additional information that might help narrow-down the problem.  The parts are working for other customers, so it is most-likely that there's some peculiarity about how you are attempting to use the part.

    Regards,

    Frank

  • 0 in reply to Frank Minich
    Prodigy 120 points

    Hi Frank, 

    I just wanted to tell you that i have accomplished to make tas1020b get enumerated. I have changed the crystal to a more precise on, I have changed one or two capacitors and i have also reviewed all the circuit again. Its is working now and getting enumerated to the boot loader.

    I have identified 3 more big steps:

    - look to the firmware code

    - connect an ADC to the tas (cypress 5381)

    - connect an DAC to the tas (cypress 4398)

    Do you have any additional suggestion for any of this tasks? Should i first connect the hardware and just the explore the firmware? Do you see any incompability with tas and these adc and dac?

    Thank you for you support,

    With my best regards,

    Nuno

  • 0 in reply to sinosoidal
    TI__Expert 4160 points

    Nuno,

    Can't say I've used either of the Cirrus parts.  You will quickly run out of RAM on the TAS1020B at higher sample rates, so I suggest a max of 48kHz.  Most ADC and DAC that I've seen used with the TAS1020B use I2S for audio and I2C for control.

    Good luck,

    Frank