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CCS/MSP430F5508: USB key code error

user4806043
Prodigy 30 points
Part Number: MSP430F5508
Other Parts Discussed in Thread: MSP430WARE

Tool/software: Code Composer Studio

Hi

In a USB keyboard application developed with CCS using MSP430F5508, the number of key code transmission data may be changed from 8 bytes to 9 bytes and sent out, causing a Babble error in the Host PC.

Situation: Repeat operation does not stop during keyboard operation.
When observing the line with a USB analyzer, the key data may become 9 bytes and a Babble error occurs in the host PC, so the key release data is not recognized and the key repeats.
Illegal key data is also normal in terms of hardware, and Host PC return ACK.

Frequency of occurrence: About 100 hours after continuous energization.
Once a phenomenon occurs, it frequently occurs. (9-byte transmission occurs in addition to normal 8-byte transmission)
Elimination of the malfunction state can be done only by turning off the power to the KB (MSP430ware Busreset does not recover)

  • 0
    TI__Genius 17960 points

    Hi,

    sorry for the delay. We're pulling in the USB expert, and will come back to you as soon as possible.

    Best regards

    Peter

  • 0
    TI__Mastermind 26410 points

    Hello,

    Very interesting that you only see this issue after >100 hours of continuous communication.  Because it works for so long before an issue, I feel like the hardware is probably okay.  

    I'm not sure what would cause this issue, but the fact that it takes so long leads me to consider possible buffer or memory leaks somewhere.  Have you taken a look at the stack to see if it's overflowing?  

    Thanks,

    JD

  • 0 in reply to JD Crutchfield
    Prodigy 30 points

    Dear DJ

    Thank you for your reply immediately.

    We will investigate buffer and memory leaks.
    The problem also occurs when the keyboard is turned on and there is almost no key input.

    Attach the log collected by the USB analyzer at the time of this failure.

    In the logs,
    ・ It seems that the data of pressing / release of the key switch is normally stored in the USB buffer.
    ・ When sending data via USB, it may become 9 bytes, but then returns to the normal 8 bytes.
    ・ After that, the frequency of transmission with 9 bytes increases. (Occurs after about 10 keystrokes)
    ・ This phenomenon can be solved by turning off the power or “CPU hard reset”.


    Currently 3/150 units have been confirmed to be defective.
    Is there a possibility that the CPU element has failed as a cause of this phenomenon?

    Thank youUSB_analyzer_log.pdf

  • 0 in reply to user4806043
    TI__Mastermind 26410 points

    Hello,

    Sorry for the delay.  Were you able to narrow down this issue any further?  

    I don't think the CPU has failed.  The MSP430F5508 is a well tested and mature device at this point and any issues have been documented in the Erratasheet: http://www.ti.com/lit/er/slaz299aa/slaz299aa.pdf 

    The only USB errata that could maybe be at play here could be USB12, but it looks like it should only happen in extremely rare cases and requires the USB PLL to be disabled.  Take a look and see if this seems possible. 

    Thanks,

    JD

     

  • 0 in reply to JD Crutchfield
    Prodigy 30 points

    Dear DJ

    Thank you for your response immediately.

    The frequency of occurrence of failure phenomena is low and investigation is not progressing.

    This product with built-in MSP430F5508 has already produced more than 10,000 units, but this defect has not been experienced before.
    The environment where the phenomenon occurs is different from the conventional one in that it is used for months without disconnecting the VBUS power supply.

    We will consider the errata USB12 that you answered.

    Thank you

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