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LDC1612: LDC1612DNT read error

Ito
Prodigy 20 points
Other Parts Discussed in Thread: LDC1612

Model:  LDC1612DNT

The IC starting sequence is as follows.
■ Starting sequence
1. Turn on the power of the LDC
2. Wait a few milliseconds. (3ms)
3. Start I2C communication (turn on EN in another buffer)
4. Write the LDC initial settings from the MCU.
5. Read the external sensor data. (I2C communication)

■ Problem
Without the second process, an error will occur in which the sensor data cannot be read.
It is known that communication will succeed if a waiting time of 3ms is inserted after starting the LDC.
(Communication error occurs when waiting time is 1ms ~ 2ms)

■ Question
Communication is successful if you put a waiting time of 3ms after starting LDC.
Is this because of the Twakeup time below?
If Wait is required from the start of LDC to the writing of the initial value setting, please let me know if there is an appropriate Wait time.

  • 0
    TI__Genius 10080 points

    Hello,

    Thank you for posting.

    The LDC1612 has an adjustable sensor startup time per channel. The timing can be varied from 1.2 µs to >26.2 ms with the SETTLECOUNTx registers. Please check the setting of these registers, keeping in mind that sensors with lower resonant frequencies or higher Q’s may require more time to stabilize.

    Additionally, section 8.1.4.1 of the datasheet has further details on the configuration of the settling conversion interval. Let me know if this helps.

    Best regards,

    Nicole

  • 0 in reply to Nicole Khoury
    Prodigy 20 points

    Hi Nicole,

    Thank you for your information.

    All registers are set to recommended values.

    SETTLECOUNTx registers : 0x000A

    I will check the setting of optimal registers.

    Sorry, we have another question. The following is the description of the data sheet. (Page 12)

    7.4 Device Functional Modes
    7.4.1 Startup Mode
    When the LDC powers up, it enters into Sleep Mode and will wait for configuration.

    →How long should we wait between "LDC powers up" and configuration (writing initial value of register)?

       (Error occurs when waiting time is 1ms ~ 2ms)

  • 0 in reply to Ito
    TI__Expert 7599 points

    Hello User,

    Thanks for your interest here. The timing for teh LDC depends on the number of channels and also dependent on the coil frequency. 

    There is an app note here that describes the relationship of conversion time with respect to the sensor frequency. 

    To answer your question about how long to wait after entering sleep mode its described in the section 7.4.2 and its a relationship dependent on Fint. 

    Let us know if this helps.