Error when using readRegister() after installing the Instrument Control Toolbox Support Package for National Instruments NI-845x I2C/SPI Interface

I just installed the Instrument Control Toolbox Support Package for National Instruments NI-845x I2C/SPI Interface (for Matlab 2023a, Windows 11). I have an USB-8451 OEM connected to a sensor through the i2c interface and I am able to create successfully an i2c device by following these commands:

>>list = ni845xlist;

>>controller = ni845x(list.SerialNumber(1));

>>i2cAddresses = scanI2CBus(controller);

>>peripheral = device(controller,I2CAddress="0x39",BitRate=100000)

peripheral =

I2CDevice with properties:

Protocol: "I2C"

I2CAddress: 57

BitRate: 100000

ByteOrder: "little-endian"

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However, the following command to read the content of register 0x92 generates the following result:

>> data = readRegister(peripheral,0x92,1);

readRegister function returned the following vendor error:

NI-845x: Unable to decipher status code 0xfffb6572 (-301710). Error -1 - Directory not found.

Can you please provide details to resolve this issue? Thanks

Answer 1

[Tridib]

Hi @Fredy, you could try these troubleshooting steps which might help solve the issue:

• Please check that you have the latest NI-845x driver, and that it matches your version of MATLAB, Windows 11, and whether your system is 32-bit or 64-bit. After updating or installing the driver, restart your computer.
• Make sure your NI USB-8451 shows up in Windows Device Manager, and that you have the right permissions to use it.
• Double-check that your sensor is powered on and connected properly to the I2C bus. Also, use the "scanI2CBus" command to see if MATLAB can find your sensor’s address.
• Confirm that you are using the correct register address (0x92) for your sensor, and follow any instructions in the sensor’s datasheet about how to read from it.
• Sometimes this error means there’s a problem with the driver or installation. Try reinstalling the NI-845x driver, and make sure your Instrument Control Toolbox and NI-845x support package are both up to date and work with MATLAB R2023a.

For more information, refer to this documentation:

https://www.mathworks.com/help/instrument/install-the-ni-845x-i2cspi-interface-support-package.html

Hope this helps!