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Reading from LM95234

Other Parts Discussed in Thread: LM95234

Hi,

I am trying to read the manufacture ID from LM95234.

In the datasheet, it was mentioned "If Command register needs to be set, then an address byte, command byte, repeated start, and another address byte will accomplish a read" --> Regarding this statement, I have few questions.

1) What is the address of Command register?  How can I know if the command register is set or not set ?

2) What is the "address byte" ? Is this the address byte of device ? 

3) What is the differences between first (red) and second address(blue) byte in the above statement ? Are they device addresses ?

4) Could you please provide pseudo like code to read the manufacturer ID from LM95234 ?

Thanks

  • Hi Janarbek,


    See Figure 22 in the datasheet:

    1. The command register is which register address you want to read from or write to. For example if you want to read the manufacturer ID, you will need to read register address 0xFE.

    2. Address byte is the address of the device which is set by the A0 pin of the LM95234.


    3. They are the same address.

    4. It is probably best explained in the Figure 22 graphic. But basically, from master to slave write to the address, write to the command register address, do a repeated start, write to the address again, the data will now come from the slave to the master.

    -Michael Wong

  • Thank you Michael.

    I have two more follow up clarifications.

    1) According to your answer to my Question 1, the "Command Register" and "Command Byte" are the same things. I asked this questions because it is not clear (actually confusing) from the datasheet because in the datasheet "Command register" is used in Page 19. It also uses "Command Byte" in the Table 8. So my question is that all "Command bytes" in Table 8 are actually register addresses ?


    2) Clear

    3) Clear

    4) So in order to read manufacturer ID from temperature sensor. I have to do following steps. Let us assume my temperature sensor device address is 18h.

    a) Master to slave write 0x18h
    b) Master to slave write 0xFE (Again 0xFE is this command or register address? )
    c) Repeated start
    d) Master to slave write 0x18h

    These are the steps needed to read the manufacturer ID, right?

    Thanks,
    Janarbek.
  • Hi Janarbek,

    1. In this datasheet the term command register is synonymous with register address.

    4. You are correct!

    -Michael Wong