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TCA-6424A Interrupt not getting generated

Amol Wadkar
Prodigy 40 points
Other Parts Discussed in Thread: TCA6424A, TCA6424, BQ32000

We are using TCA6424A in our application. We have configure 5 pins of port 2 as inputs. Whenever level of input is changed a interrupt is generated. The system functions successfully for a 3-4 days and suddenly TCA6424 stop generating interrupts.


We have an additional device  BQ32000 connected on same I2C bus. Which works normal. Also when the problem occurs ports of TCA6424 configure as outputs are working normal.


So problem is that TCA6424 stops generating interrupts. We have conform the same by using an DSO.

  • 0
    TI__Genius 9860 points
    Moving to I2C forum for support.
  • 0
    TI__Mastermind 30280 points

    Amol,

    It may depend on whether you are using the TCA6424A or the TCA6424 (non-A version).

    Unfortunately, your post says both and therefore it is impossible for me to determine which one you actually meant.


    Can you do me a favor and copy the FULL Part # with Package Designation directly from your Schematic or BOM and paste it into your follow-up post?

  • 0 in reply to Brian Berner
    Prodigy 40 points

    Brian,


    I am using TCA6424A UQFN package. Please find the schematic below:

  • 0 in reply to Amol Wadkar
    TI__Mastermind 30280 points

    Amol,

    Your first response says you have "5 pins of port 2" configured as inputs, but your schematic shows all 8 channels of port 2 configured as inputs.

    Do only 5 of the ports stop generating interrupts, or was there a typo in your original post?

    You also said you used DSO to verify the issue. What does DSO stand for?

    Can you provide me a scope shot showing an I2C read AFTER the problem has occurred? You should be able to Read the Input Port 2 Register (Reg. 0x02) , triggering on SCL or SDA falling.

    Can you also read the Configuration Port 2 Register (Reg. 0x0E)?

    After you read the Port 2 registers, can you switch the oscilloscope to trigger on /INT falling and monitor the scope for events?

    I'd like to be 100% sure that the Interrupt DOES NOT EXIST, as opposed to the Interrupt being generated and cleared.


    As you can see on page 18 of the TCA6424 (non-A) datasheet, the Interrupt Errata outlines a condition where the Interrupt is generated but incorrectly cleared. I'm not saying it is the same issue, I'm just trying to be sure it is NOT a known issue with the old device.

  • 0 in reply to Brian Berner
    Prodigy 40 points

    Brian,

    8 pins have been configured as inputs but in firmware we are using only 5 inputs and 3 have been kept as reserved.

    By DSO i was referring to Digital Oscilloscope.

    According to my observation interrupts are not getting generated, the problem gets solved when we reconfigure TCA6424 using following code.

  • 0 in reply to Amol Wadkar
    TI__Mastermind 30280 points

    Amol,

    Writing 0x1F to register 0x0E (Config Port 2) will keep pins P23 (DOOR_SENSOR2), P24 (WIEGAND1_TAMPER), P25 (WIEGAND2_TAMPER), P26 (WIEGAND3_TAMPER), and P27 (WIEGAND4_TAMPER) configured as inputs after start-up.

    If this is the desired configuration of the device, then I expect the INT pin to work as defined in the datasheet.

    Please follow-up if you still have any questions.

  • 0 in reply to Brian Berner
    Prodigy 40 points

    Brian,

    Yes that is indeed the desired configuration, but TCA6424A stop generating interrupts which is my query. We have 2 devices over I2C bus other device is RTC(BQ32000).


    Please help.