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A
Akella
Visitor II
December 5, 2016
Question

HTS221 Reset registers to Default

  • December 5, 2016
  • 1 reply
  • 580 views
Posted on December 05, 2016 at 20:44

Hi.

Sorry for my English.

specified in the datasheet

 If a slave receiver does not acknowledge the slave address (i.e. it is not able to receive because it is performing some real-time function) the data line must be kept HIGH by the slave. The master can then abort the transfer. A LOW to HIGH transition on the SDA line while the SCL line is HIGH is defined as a STOP condition. Each data transfer must be terminated by the generation of a STOP (SP) condition.

Sensor sets the data line in high. The microcontroller by sending an address sensor receives NACK, and stops communication.

After that, registers AV_CONF, CTRL _REG1, CTRL _REG2, CTRL_REG3 reset to its default state (All read operations read the default values).

This situation occurs if the ODR> 0. (1 Hz 7 Hz 12,5 Hz)

Why is this happening?

How do I check the conversion is complete without RDY pin (ODR>0)?

Best regards, Sergey

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    1 reply

    S
    Seb
    ST Employee
    December 23, 2016
    Posted on December 23, 2016 at 18:30

    Make sure CS pin is high level to configure as I2C mode (100kHz is more than enough for a humidity sensor)

    Remember that the sub address bit 7 should be set to 1 to use autoincrement when reading status, humidity and temperature registers. This makes the communication shorter and efficient.

    Haven't tested ODR = 1 Hz so can't help out here.

    Repeat( one short mode, wait 1 second, read back the result registers) should work fine.

    Humidity changes and detection is a quite slow process (unless using ventilation) compared to pressure.

    Good luck!

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