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TMP1827: Hardware confirmation

Suryanarayanareddy Obireddygari
Prodigy 30 points
Part Number: TMP1827

Tool/software:

Hi  Team,

I am using STM32F407 controller and trying to interface with one wire device TMP1827

I am using TMP1827EVM board and using TMP1827

 I have couple of requests here:

  1. I have made the circuit diagram as mentioned below but can you please confirm once, the pull up resistor value need to be used (390ohm is used in eval board but in datasheet it mentioned as 750ohm to 2.2kohm).
  2. How can I know the Unique id of the device using the EVM tool. This is needed to compare if what I am reading is correct.
  3. With the below circuit i am able to reset the bus (i.e., I sent 0x00h and also got 0xFCh as response) but when i am sending the SEARCH ADDRESS 0xFC and I am not getting any response can you please help me if i am missing something.
  • +1
    TI__Mastermind 41235 points

    1. You should follow the datasheet guidelines in your circuit design.

    2. The EVM GUI is able to query the unique ID on the address tab of the GUI. It's not necessary to know the unique ID when there is only one device on the bus as SkipROM can be used for communication.

    3. If you are using UART to emulate 1-Wire, the reset pulse could not be 0x00. There must be a high period after the low pulse. Additionally, the baud rate has to be different for reset pulse and the normal communication that follows. This is not a trivial software project; have you reviewed our example code? https://www.ti.com/tool/download/TMP1826-1-WIRE-CODE

    thanks,

    ren