One Wire

1 Wire® field network

The 1 Wire® field network is a standard protocol based on a single wire, as the name indicates, that includes many devices and sensors frequently used in the industrial and building automation environments. On the market actually there are numerous components based on this communication protocol, that have a very interesting price/oerformance ratio. This is moreover improved by a simple and cheap connection modality, infact only three wires are necessary: two for power supply and the third for the bidirectional communication; on this wires all the devices can be connected in network modality by chosing the best physical position.
Among the available devices we can list the following ones:

The 1 Wire® protocol is provided of all the communication tecniques that allow an high transfer rate and a big security on data validity. This is possible thanks to univocal addressing mode, polinomial CRC controls, many check commands and complex management algorithms.

grifo® has the knowledge on 1 Wire® protocol management and it can be applied to each card provided of at least one digital I/O bidirectional line. This know how has been introduced in some cards that are so able to manage more lines with this protocol. These implementation coincide with a firmware that communicates at high level with the user on one side and that manages the 1 Wire® protocol, thus the devices, on the other side. By using a list of commands properly developed, the user can easily communicate with all the available devices by simply transmitting and receiving the required data and without taking care of timing, line direction, CRC, conflicts, etc.
The developed commands are:

  • Reset of 1 Wire® BUS
  • Write bit on 1 Wire® BUS
  • Read bit from 1 Wire® BUS
  • Write byte on 1 Wire® BUS
  • Read byte from 1 Wire® BUS
  • Read ROM code on 1 Wire® BUS
  • Match ROM code on 1 Wire® BUS
  • Skip ROM code on 1 Wire® BUS
  • Alarm search on 1 Wire® BUS
  • As described the available commands don't support the high level management of several devices for each line in fact for example it is not implemented the "Search ROM code" command usefull to recognize the ROM codes of the connected devices. A network connection of more 1 Wire® devices can be anyhow managed through the low level developed commands: these can be used first to locate the code of the connected units and then to address and manage them separately.


    The management of 1 Wire® protocol is performed by a proper firmware that executes the already described operations; this firmware is supplied as executable code already saved in the card and it is complete of:

  • User manual that describes the devices connection and the available commands use
  • Demo programs for PC that, thanks to a serial communication with the used card, communicates with some devices connected on 1 Wire® network. This demos are provided in executable format for Windows and in source format.


    The described management firmware is available for the following grifo® cards:

    and on specific request it can be implemented also on numerous other cards that have at least one digital I/O bidirectional line. For detailed information please contact directly grifo®.

    Page up-dated at September 02, 2008

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