SPMA057D January   2018  – June 2022 TM4C1290NCPDT , TM4C1290NCPDT , TM4C1290NCZAD , TM4C1290NCZAD , TM4C1292NCPDT , TM4C1292NCPDT , TM4C1292NCZAD , TM4C1292NCZAD , TM4C1294KCPDT , TM4C1294KCPDT , TM4C1294NCPDT , TM4C1294NCPDT , TM4C1294NCZAD , TM4C1294NCZAD , TM4C1297NCZAD , TM4C1297NCZAD , TM4C1299KCZAD , TM4C1299KCZAD , TM4C1299NCZAD , TM4C1299NCZAD , TM4C129CNCPDT , TM4C129CNCPDT , TM4C129CNCZAD , TM4C129CNCZAD , TM4C129DNCPDT , TM4C129DNCPDT , TM4C129DNCZAD , TM4C129DNCZAD , TM4C129EKCPDT , TM4C129EKCPDT , TM4C129ENCPDT , TM4C129ENCPDT , TM4C129ENCZAD , TM4C129ENCZAD , TM4C129LNCZAD , TM4C129LNCZAD , TM4C129XKCZAD , TM4C129XKCZAD , TM4C129XNCZAD , TM4C129XNCZAD , TMP1826 , TMP1826 , TMP1827 , TMP1827

 

  1.   Abstract
  2.   Trademarks
  3. 1Introduction to 1-Wire
    1. 1.1 Bus Requirements
    2. 1.2 Powering
  4. 2Functional Description
    1. 2.1 Signaling on 1-Wire
    2. 2.2 Address Format of the 1-Wire Device
    3. 2.3 Typical Communication Flow on the 1-Wire Bus
  5. 3Functions Available in TivaWare for C Series for 1-Wire Module
  6. 4Enumeration
    1. 4.1 Legacy Search Algorithm
      1. 4.1.1 Steps of the 3-Bit Search Algorithm
    2. 4.2 Fast Search Algorithm
  7. 5Summary
  8. 6References
  9. 7Revision History

4 Enumeration

When multiple devices are present on the bus, the host must know the 64-bit device address to match the required devices. Enumeration is performed to obtain the 64-bit address of the devices on the bus and therefore what classes of devices are available.

The legacy mode for search address operation described in Section 4.1 is performed by executing two steps, iteratively:

  1. Read two bits from the devices (the actual bit value and its complement)
  2. Write the appropriate bit that defines the search path in the enumeration algorithm. Devices with the corresponding bit equal to the written bit remain active, while the rest go to the idle state and wait for the next reset command.

This cycle is done for all 64 bits and the 64-bit device address is assembled at the end of the iteration.

TMP1826 supports fast search operation which greatly simplifies the 64-bit device address and is described in Section 4.2