Digital I/O

cancel
Showing results for 
Search instead for 
Did you mean: 

NI 8451 driving 3.3V circuitry

Solved!
Go to solution

Hello,

 

I'm wondering if it's at all possible to read/write to 3.3V (ideally 1.8V) circuitry on the I2C lines of the USB 8451.  As best as I understand, it's a 5V only bus.  Unfortunately, the part doesn't come in higher voltage and I have haven't found a NI device that reads/writes to I2C on any other voltage than 5V.  Any help is appreciated.  Thanks.

 

=Chris 

0 Kudos
Message 1 of 2
(2,888 Views)
Solution
Accepted by topic author Klepackage

Hello,

 

Take a look at the 8451 specifications. This says that the I2C interface can read an input as high in a range from 2.0 to 5.8 V. The high output is specced to be above 2.0 V.

 

Depending on your external hardware requirements, you can use these signals or use some sort of external circuitry for a more disciplined value or to limit the output to a lower value (1.8 V).

---

Peter Flores
Applications Engineer
0 Kudos
Message 2 of 2
(2,866 Views)