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LP55231: Handling of EN in RESET processing

Kaji@PAN
Mastermind 7360 points
Part Number: LP55231

Hello,

I would like to ask you a question about the LP55231.
(Question 1)
When writing 0xFF to the reset register, does ACK of I2C communication return?
(Question 2)
After writing 0xFF to the reset register, is it necessary to wait until CHP_EN becomes H (bit)?
(Question 3)
After shifting from NORMAL mode to RESET mode, if EN=H, the response will not be returned from LP55231.
Are there any problems with EN=H?

Best regards,

  • 0
    TI__Expert 6440 points

    Hi Kaji,

    (1) Yes, it still follows the standard I2C format.

    (2) If you want to enable the device after resetting, you need to write the CHIP_EN bit to hign after reset, or the device will hold on standby mode.

    (3) No, no matter EN = H/L, after you setting to RESET mode, the device will set all register to default value, and after you set both EN = H and CHIP_EN = H, the device will start up again.

    Thanks!

    BR, 

    Ives Li

  • 0 in reply to Ives Li
    Mastermind 7360 points

    Thank you for your reply.

    The reason I am asking you is because the LP55231 does not respond after going from NORMAL mode to RESET mode.
    So I'm looking for the cause.
    I understand answer 2, but is it necessary to wait until CHIP_EN is set to H?
    In answer 3, when writing 0xFF to the reset register, which setting should the EN pin be set to, H or L?
    Which is fine?

    Best regards,

  • +1 in reply to Kaji@PAN
    TI__Expert 6440 points

    Hi,

    What do you mean about "wait until CHIP_EN set to high". After reset, the CHIP_EN will be set to low which is the default value, so you have to write CHIP_EN to high to let the device enter NORMAL mode.

    And for both H and L of EN is OK, because the after reset, the CHIP_EN = 0, and the device and enter NORMAL mode only both CHIP_EN and EN are high.

    Thanks!