readRegister function undefined when used in GUIDE

Hi All,

I'm a hobbyist attempting to create a basic gui that will sample data from an I2C based current sensor that is attached to my raspberry pi. I have written and successfully tested a class that correctly samples this data when run via a standard Matlab Script. However, when I attempt to code this into a gui, I get the following error message when I try to call the readRegister function:

Undefined function 'readRegister' for input arguments of type 'double'.

From doing research, I believe that matlab somehow cannot locate the readRegister function when called from the gui. This confuses me since the function easily runs if I simply call it from the command line, for example this works outside of the gui:

config_values = readRegister(sensor.i2cLink,register_address,'uint8',2);

where sensor.i2cLink and register_address are specifically defined (and verified to exist when debugging).

Does anyone know of a work around to this?

Answer 1

[Walter Roberson]

readRegister requires an object of class device but inside your GUI you are instead passing it an object of class double. In particular you should check sensor.i2cLink to see if it is [], the empty array, such as if the link configuration had not been done yet or had failed.

[Christopher Gates]

You were right (and saved my evening). My i2cLink variable had been defined but wasn't being passed correctly from one function to another so it was cleared to []

Thank you for your help!