• State TI Thinks Resolved
  • Locked Locked
  • Replies 9 replies
  • Answers 3 answers
  • Subscribers 21 subscribers
  • Views 355 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

BQ32000: Years register default value

Hailiang Zhang
Genius 11000 points
Part Number: BQ32000

Tool/software:

Hi Team,

Customers reported that the value of the Years register read from the initial device is 0x6f, which is different from the default value in the datasheet. And I see that the default value is 0xxx. I want to know what the default value is? Any suggestions for this issue?

Regards，
Hailiang

  • 0
    TI__Guru** 107280 points

    Hi Hailiang,

    x means the value is not deterministic on every power cycle, there is no silicon default value. 

  • 0 in reply to Noel Fung
    TI__Genius 11000 points

    Hi Noel,

    So what about the initial device that TI shipped? What is the default value?

    Regards，
    Hailiang

  • 0 in reply to Hailiang Zhang
    TI__Genius 11000 points

    Hi Noel,

    The initial value of register 00-06 is undefined and may not be a valid value? If you have the initial values ​​when the device was shipped, please share it.

    Regards，
    Hailiang

  • 0 in reply to Hailiang Zhang
    TI__Guru** 107280 points

    Hi Hailiang,

    Only those register bits marked as x has no initial (silicon default) value, they are usually used as read back purpose. For example, although we can write data to TOD registers, but the main purpose of these registers are read back. 

    Configuration purpose registers usually come with silicon default value, for example, trickle charger registers have initial value. 

  • 0 in reply to Noel Fung
    TI__Genius 11000 points

    Hi Noel,

    I know there are no reset default values ​​for these registers. Customers found that the initial value of the register was an invalid value, causing their RTC driver to fail to load. So wondering if this is normal. Can you please confirm? Or please confirm whether TI will configure the initial value when shipping the devices?

    Regards,
    Hailiang

  • 0 in reply to Hailiang Zhang
    TI__Guru** 107280 points

    Hi Hailiang,

    Initial value (if exist) = silicon default value, this is hard-coded in the chip, it does not need manual configuration. 

    For read purpose register, there is no normal or invalid initial value. Read purpose register is intended to read back the operation status. At initial, it is not operated, what is the point of validating the read purpose register value?

  • 0 in reply to Noel Fung
    TI__Genius 11000 points

    Hi Noel,

    Pls refer to the comments form customer.

    " Rtc device can't register successfully if the time register has invalid value which makes the  manufacturing  test fail.

    Do you have any suggestions about this? I think We should not be the only ones facing such a problem."

    Do you think it doesn't make sense for customers to read these registers during system initialization? Or the user should initialize these registers. 

    When the customer initialized the system, he found that the values ​​of these registers were invalid. For example, the value of the DAY Register exceeded 7. Is this an issue?

    Regards，
    Hailiang

  • 0 in reply to Hailiang Zhang
    TI__Genius 11000 points

    Hi Noel,

    I think the user needs to perform initialization. Reading the register directly and verifying its validity doesn't seem to make sense. Right? 

    Could you pls help confirm it is normal to directly read these registers and obtain invalid data?

    Regards,
    Hailiang

  • 0 in reply to Hailiang Zhang
    TI__Guru** 107280 points

    Hi Hailiang,

    Maybe there is a confusion on the definition of initial value.

    Initial value, sometime called reset value, is the silicon default value of a device after it is Vcc powered up (if it has Power-On-Reset circuitry) or after it is reset. 

    Write purpose register has silicon default value.

    Read purpose register usually does not have silicon default value. 

    After Vcc power up, the RTC will run. However, the RTC is not possible to know the present time/day/year after it is powered up. If you read the TOD information, it is not going to be something you would expected.

    After Vcc power up, we should write the TOD to the device, wait for at least one second until the RTC updates the TOD. After that, we should be able to read back correct TOD.