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TLA2024: Configuration Register (RP = 01h) reset value seems inconsistent

Florian Curinga
Prodigy 20 points
Part Number: TLA2024

Hello,

We are using the TLA2024 as part of one of our products. 

In order to test this product after production, we wish to perform a health check of the TLA2024 that is installed in it. To do so, we were thinking about reading the Configuration Register (RP = 01h) of the TLA2024 and check that it is the expected value. According to the datasheet, this value should be "8583h" after a reset.

However, tests on our side show that this register can take a different value after reset (in this case, we power-cycle the VCC). In particular the value "B5B3h" can sometimes be read in the Configuration Register after a reset of the TLA2024.

Is this to be expected, or should we consider such a component to be faulty? Additionally, if there is a better TL2024 health check process you can suggest I would be interested in knowing about it.

Best regards,

Florian

  • 0
    TI__Guru* 93305 points

    Florian,


    Normally, I would also use the reading of the configuration register to test the communications of the device. It's strange that you would get something other than the default setting after cycling the power on the device.

    There are a few things I would try to debug this. First, I would look at a scope shot of the I2C communications to see if there isn't a problem with the digital lines. I would also try reading the configuration register multiple times to see if the value isn't changing (it shouldn't but this also might lead to a problem with the I2C).

    I would also try reading the conversion data register to see if it matches what is on the input pin. You may need to put on some small voltages to the input prior to the power-up to differentiate between different voltage readings. The configuration of B5B3h shows a different input channel setting than default (AIN2-AIN3 instead of AIN0-AIN1). You could also try multiple readings of the conversion data register immediately after the power up to see how long it takes to make the first conversion. The non-default configuration setting has a different data rate as well.

    You can also check your inputs prior to power up. It's possible that a high input voltage was left on an input pin, which maintains power to the device. This would allow the device to retain a previous configuration, even if the power is removed from VDD.

     Is this the only I2C device on the bus? Could this be a problem with another device with the same address?


    Joseph Wu

  • 0 in reply to Joseph Wu
    TI__Guru* 93305 points

    Florian,

    I haven't heard from you for a while, so I thought I'd check in on your TLA2024 issue.

    As I mentioned in my last post, there were a few things that I wanted you to check to debug the issue. Some if it involved looking at the I2C communications, but other things to try involved testing the different channels with different voltage inputs.

    I'll close this thread for now. If you are still having problems with this device, post back and we can continue working on this problem.

    Joseph Wu

  • 0 in reply to Joseph Wu
    Prodigy 20 points

    Hello Joseph,

    Thanks for your answer and apologies for my delay.

    I just got the opportunity this morning to try the solution you suggested, it indeed appears that a high voltage level was still present on the AIN channels during the reset sequence due to a faulty hardware. Patching it caused the issue to disappear, tests show now that the right register is consistently read by our MCU after a reset sequence. 

    Thanks again for your support.