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DAC8775: Clearing bit for status register

Takeshi Sasaki
Expert 4480 points

Part Number: DAC8775

Hi Team,

I wanted to confirm how to clear the bit of the status register. In the datasheet page 41, it says "Whenever one of these status bits is set, it remains set until the user clears it by writing '1' to corresponding bit on address 0x0B.", at 8.3.10 Status Register. Is it correct description? Status bit is set '1' when alarm occurs, so writing '0' is the correct description for clearing bit of the status register. Is ti correct my understanding? Thank you for your support. 

Best regards,

Takeshi Sasaki

  • 0
    TI__Mastermind 46290 points
    Sasaki-san,

    The datasheet described procedure is correct. Write a 1 to the corresponding bit in register 0x0B in order to clear the alarm condition. Writing a 0 should not clear the alarm.
  • 0 in reply to Kevin Duke
    TI__Expert 4480 points
    Hi Kevin,

    Thank you for your clarification. So, writing bit '1' to the corresponding bit in the 0x0B, the status register goes to '0' as default within a certain period of time, is it correct? Also, I've one more question, is it faster reset way rather than performing software/hardware reset or power on reset? Performing those reset takes 8us as minimum, the customer wonders if the writing bit is faster reset way or not.

    Best regards,
    Takeshi Sasaki
  • 0 in reply to Takeshi Sasaki
    TI__Mastermind 46290 points

    Takeshi Sasaki said:
    So, writing bit '1' to the corresponding bit in the 0x0B, the status register goes to '0' as default within a certain period of time, is it correct?

    Yes.

    Takeshi Sasaki said:
    Also, I've one more question, is it faster reset way rather than performing software/hardware reset or power on reset? Performing those reset takes 8us as minimum, the customer wonders if the writing bit is faster reset way or not.

    POR versus HW reset will basically trigger the same behavior in the device. In most situations I imagine it to be easier to trigger the HW reset than to toggle power as required to trip the POR circuit. The core mechanics concerning the actually loading of OTP etc are very identical once either of those sources are tripped. In my opinion the HW reset is the most reliable, though.

  • 0 in reply to Kevin Duke
    TI__Expert 4480 points
    Hi Kevin,

    Thank you for your comments, but I'm sorry it seems a little bit different from what I meant in the second question. In my understanding, DAC8775 has 3 different reset way for the 0x0B register, 1. writing "1" corresponding to bit, 2. software/hardware reset, and 3. POR. The 2. and 3. take minimum 8us for resetting as described in the datasheet, however, resetting by 1. should take shorter time rather than 2. and 3., such as 0.5us, 1us, or 2us, and so on, like <8us. Is it correct? The customer wants to select 1. for the resetting since it should take shorter time than 2. and 3. So, I'd like to confirm the writing "1" should take for resetting less than 8us.

    Best regards,
    Takeshi Sasaki
  • 0 in reply to Takeshi Sasaki
    TI__Mastermind 46290 points
    Sasaki-san,

    I see. I understand the question now.

    I would say in terms of speed the ranking from fastest to slowest would be:

    1. Writing to 0x0B
    2. HW Reset
    3. POR

    Overall speed of option 1 has some relationship to the SPI clock frequency, but it's very small compared to the overall time for the complete reset.
  • 0 in reply to Kevin Duke
    TI__Expert 4480 points
    Hi Kevin,

    Thank you for your comments. Now it's clear for me. Thanks!