USB-6423 ID Pin

Use the ID pin to connect the USB-6423 to a 1-wire EEPROM.

The ID pin on the USB-6423 allows you to read from and to write to a 1-wire EEPROM. You can use it to build systems that can support the following workflows and more.

  • Confirm the identity of the DUT connected to the USB-6423.
  • Confirm that cables are connected properly.
  • Read and save fixture-specific information, such as calibration constants, mating cycles, and more.
  • Read and save setup information from a connected information, such as wiring or virtual channel information.

The ID pin API is available in LabVIEW, C, C#, and Python.

Supported EEPROM Families

The USB-6423 supports a limited number of EEPROM families. Verify that the family code of your EEPROM is compatible before using it.

Refer to the following table for a list of supported family codes.

Table 12. EEPROM Family Codes Supported by the USB-6423
Family Code Example Device EEPROM Size
0x01 DS2401+ N/A
0x14 DS2430A+ 32 bytes
0x2D DS2431+ 128 bytes
0x23 DS24B33+ 512 bytes
0x43 DS28EC20+ 2,560 bytes

Connecting the ID Pin to an EEPROM

  1. Verify that the family code of the EEPROM is compatible with the USB-6423.
  2. Connect the I/O pin of a supported 1-wire EEPROM to the ID pin.
  3. Connect the ground of a supported 1-wire EEPROM to digital ground.
    Figure 9. USB-6423 ID Pin to 1-Wire EEPROM Connection Diagram


    Note NI recommends connecting to digital ground, but you can connect to chassis ground instead for convenience.

VIs for Reading from and Writing to the EEPROM

Use the DAQmx Read ID Pin Memory and DAQmx Write ID Pin Memory VIs to read from and write to the EEPROM connected to the ID pin on the USB-6423.

The DAQmx Read ID Pin Memory VI reads and returns the data stored in the memory attached to the specified ID pin. Use the DAQmx Read ID Pin Memory VI to read the following information from the EEPROM connected to the USB-6423.

  • The format code of the data.
  • The data itself.
Figure 10. DAQmx Read ID Pin Memory VI


The DAQmx Writes ID Pin Memory VI writes the supplied data and format code to the EEPROM connected to the specified ID pin. Use the DAQmx Write ID Pin Memory VI to write the following information from the EEPROM connected to the USB-6423.

  • Format code of the data.
  • The data itself.
Figure 11. DAQmx Write ID Pin Memory VI


The following image shows an example of a simple VI to write to and read from a connected EEPROM.

Figure 12. Example VI


  1. DAQmx device property node that you can use to access the ID pin properties.
  2. Format code that denotes a UTF-8 string.
  3. Loop through each ID pin.
  4. Only access the ID pin if it is connected to the EEPROM.
  5. DAQmx Read ID Pin Memory reads from the selected ID pin.
  6. DAQmx Write ID Pin Memory writes to the selected ID pin.
  7. Function that converts data from a string to a binary array.

The following table lists the data format codes that are supported by the USB-6423.

Table 13. Data Format Codes Supported by the USB-6423
Format Code Description
0x01 UTF-8 String
0x10..0x7F Available for users
other Reserved

You can use property nodes to store the following information. To find the properties related to the ID pin, right-click the DAQmx device property node and select Identification » ID Pin.

  • Family code of the EEPROM.
  • Size of the EEPROM.
  • Serial number of the EEPROM.