Device used:
sbRIO-9607
sbRIO-9684
sbRIO-9687
Software:
LabVIEW 2017
Hello,
First of all some context.I have a testbench with a sbRIO-9607 with its PFGA as a controller and its processor as the real-time device, then a sbRIO-9684 as a link between the sbRIO-9607 and the sbRIO-9687, and finally the sbRIO-9687 using its I/O ports, etc. So far so good, it's a phenomenal testing platform.
Now, I have to connect it with another device via SPI communication and I have some troubles.
I'm using the NI SPI IP v1.3.0.1 package for the communication and I have been able to pull the pulse trains along the LVTTL lines of the sbRIO-9687. However, when measuring them I see that the logic voltage "1" is 3.3V and the logic voltage "0" is 1.5V, and this does not fit with what it says on the sbRIO-9607 datasheet: "output low voltage when sinking 3 mA 0.0 V minimum and 0.4 V maximum". The logic voltage "1" is fine but the logic voltage "0" of 1.5V is too high.
Could it be a high noise immunity mechanism or something like that?
I don't know what I'm doing wrong. I don't know if the problem is in the I/O settings or I have to change something in the hardware (some switch, jumper...).
Thanks in advance,
David