8451 SPI Error with ADXL346

[lgbav8r]

All,

I have an error when trying to use the Analog Devices ADXL346 with the NI USB-8451 over SPI.  I recieve the following error:

"Error -301713 occurred at Property Node (arg 1) in SPI_Simple_forum.vi

Possible reason(s):

NI-845x:  An input parameter, or combination of parameters, is invalid. An example of this error may be setting an invalid baud rate or enabling I2C ACK polling while using 10-bit addressing."

The interesting thing about this is it only occurs when the I/O voltage is anything but 3.3V.  When it is 3.3V I do not get the error.  However, the I/O voltage of the device is set at 2.5V so I believe I need to set the 8451 I/O voltage to 2.5V and thus get the mentioned error.  Because the error only appears when I change the voltage, I can conclude it doesn't like the voltage selection but I don't know why.  Any insight?  Thanks.

My VI, and datasheet are attached.

[Jeff.St · Accepted solution]

Hey,

Sorry, but I'm pretty sure you're getting the error because the USB-8451 is not capable of variable voltage levels.  If you look at the NI-845x Hardware and Software Manual, in Appendix A, it does not mention anything about being able to change the voltage levels on the USB-8451.  If you scroll down a little to the USB-8452 section, it does.  If you have any more questions about this, please feel free to ask!

Best,

[lgbav8r]

Thanks Jeff.  I see that.  I basically copied the NI example for reading and trimmed it down for this chip.  I guess the example is more geared to the 8452.  So does this mean the 8451 cannot work with this accel since the supply voltage is 2.5V and a supply voltage of 3.3V would exceed the maximum for this device?

[Jeff.St]

I didn't look at the spec sheet for the ADXL346, but I wouldn't use an out of spec voltage with it.

[lgbav8r]

I have acquired an 8452 and with that set to 2.5V the ADXL346 works perfectly