The 14 DIO on the digital sidecar are connected to the NI 9403 digital module, which specifies 5v TTL. a 5v TTL input is compatible with 3.3v CMOS output. Vih for 5v TTL is 2v, while Voh for 3.3v CMOS is 2.4v. There is reduced margin, but it was designed to work. I have not tried it, however. Sparkfun has a nice tutorial on logic levels:
https://learn.sparkfun.com/tutorials...s/introduction. However, because the digital sidecar has a 5v pullup, you should not connect them to the Raspberry Pi, but could be used with 5v tolerant 3.3v logic.
I could not quickly find a spec on the DIO for the Raspberry Pi, so you would have to make sure it conforms to 3.3v CMOS logic levels.
Other signals on the digital sidecar do not go directly to the 9403 and would have to be evaluated independently (like I2C).
Quote:
Originally Posted by McGurky
Like you have said, and others have tried, running a 3V3 signal into the cRIO will not trigger a logic high for the cRIO. You must use some type of logic level converter(LLC) to perform the task you are desiring. (3V3-->5V)
Also, here is a relevant thread from last year: http://www.chiefdelphi.com/forums/sh...d.php?t=101407 |
Do you have another example besides that thread? It sounds like the problem was not powering the IMU from the right power source, rather then a logic conversion problem.