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PCM6360-Q1: I want to check the open circuit status of Mic

guilin you
Prodigy 40 points
Part Number: PCM6360-Q1

Tool/software:

I want to check the open circuit status of Mic
The 0x2E register on Page 0 in the manual is self-clearing bit for open circuit detection and cannot continuously obtain an open circuit state.
Can the open circuit state be continuously detected.

  • +1
    TI__Mastermind 27290 points

    Hi Guilin,

    Yes, you can continuously check the fault status of registers without clearing the bit in the LIVE registers. This can be read in page 1 - 0x2d:0x33 registers

    CH1_LIVE register is page 1, 0x2E [7]

  • 0 in reply to Daveon Douglas
    Prodigy 40 points
    The current hardware adopts the DC Coupled Microphone Single End Input Connection connection method as shown in Figure 38.
    I want to detect an open circuit fault.
    Read 0x31 register (CH4_LTCH Register) from Page 0 and 0x31 register (CH4_LIVE Register) from Page 1
    The same operation method (disconnect the Mic of Channel4)
    There was a fault detected in the 0x31 register of Page0, but the fault was cleared by itself after a period of time.
    There is no fault detected in the 0x31 register of Page1.
    Currently, no Mic disconnection fault has been detected in the 0x31 register of Page1.
    May I ask if the settings of any registers required before detecting faults are related to the specific hardware connection method.
  • 0 in reply to guilin you
    TI__Mastermind 27290 points

    Hi,

    The open circuit fault trigger is designed based on an ECM microphone connection under the following conditions:

    Since the input signal is in single-ended configuration then 1 of the 2 conditions for an open circuit fault are already triggered. I suggest adjusting the S2G and S2MICBIAS detect threshold in register 0x66. 

    Configure this register based on the measured DC voltage of INP/M pins when an actual open circuit is simulated.

  • 0 in reply to Daveon Douglas
    Prodigy 40 points

    I modified the value of the 0x66 register, but it still has no effect.

    When unplugging Mic, the values of the 0x2E~0x32 registers on Page 0 will change (0x00->0x08->0x00), but the values of the 0x2E~0x32 registers on Page 1 will not change.

    Is there a demo or documentation for setting the timing and specific register values for detecting the open state of channels 1, 2, 3, and 4 in single end connection mode

  • 0 in reply to guilin you
    TI__Mastermind 27290 points

    Hi Guilin,

    The diagnostics registers on page 1 are live detection registers that monitor the status of a fault continuously. The latch registers can only read 0 if the live register does not detect a fault or the latch fault is masked.

    You can measure the voltage of the INx pin with a multimeter and double check the IC is reading this correctly in page 1 registers 90 to 117. This is explained further in section 8.1 of the document linked below.

    I suggest setting the maximum and minimum thresholds for your fault testing and verifying the voltage on the respective pin with a multimeter.

    PCM6xx0-Q1 Fault Diagnostic Features

  • 0 in reply to Daveon Douglas
    Prodigy 40 points

    P can detect ground short circuit, but P cannot detect microphone bias short circuit.
    Is there a switch configuration register for P to short circuit microphone bias?

  • 0 in reply to Daveon Douglas
    Prodigy 40 points

    This is our current schematic. Please confirm if the schematic is correct.

  • +1 in reply to guilin you
    TI__Mastermind 27290 points

    The schematic connection is correct.

    When recording what is the DC voltage measured at MIC4+_IN? What is the short-to micbias threshold set to?

  • 0 in reply to Daveon Douglas
    Prodigy 40 points

    Thank you for the answer and explanation. The reason has been identified.
    Detected input voltage of 7.45V through measurement
    0x66 register configured as 0x8F
    The current detected voltage does not meet the requirement of 8V-7.45V<0.45V, resulting in the inability to detect faults
    Modified the circuit by reducing the resistance value, so that the input detection voltage reaches 7.7V, meeting the fault detection condition of 8V-7.7V<0.45V.