Online Development Notebook > Index > Programming Overview > Device Commands > Read1Wire

Read1Wire - Read a byte from a 1-wire bus⁄device

VERSION 1.30+ of the firmware, VERSION 36+ of the DLL


This is a function to send a 1-wire (MicroLAN) byte read on the previously selected port pin.

Command Syntax: (USBm.dll)

USBm_Reset1Wire( device, dataarray )

The USBm_Reset1Wire function syntax has these parts:

Part Description
device A zero-based index to address the appropriate USB device.
dataarray The function causes this variable to be changed to the value read from the bus. Minimum array size of 8.


This command does not set the port direction pins or select the pin to use as the 1-wire bus - it is the Reset1Wire command that does this.

VB Declaration

Public Declare Function USBm_Read1Wire _
    Lib "USBm.dll" _
        (ByVal device As Byte, _
               ByRef dataarray As Byte)_
   As Integer

VB Example

Dim dataarray(8) As Byte
    USBm_Read1Wire 3, dataarray(0)

This code fragment addresses U4x1 device #3, and reads a byte from the 1-wire device. The read value is in "dataarray(0)".

C Prototype

int USBm_Read1Wire ( unsigned char device, unsigned char * data );


C Example

USBm_Read1Wire ( 3, dataarray );

This code fragment addresses U4x1 device #3, and reads a byte from the 1-wire device. The read value is in "data".



Returns a byte value that is read from the 1wire device.

Raw Command

See Read1WireBit

Hardware:  U401 USB Interface    U421 USB Interface   U451 USB Interface

Programming:  USBm DLL Programming    Download Files

Application Notes:  U4x1 Application Notes    Misc Applications and Information    FAQ

While every effort has been made to make sure that the information posted on this site is correct, the author can not be held liable for any damages whatsoever for losses as a result of the application of this information. Use this information at your own risk.

USBmicro can design your custom and semi-custom USB product. Email about USB design can be directed to " Robert " at

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