2015 Beta Testing - The Components are Here.

[Joe Hershberger]

Originally Posted by AustinSchuh

Bummer, thanks for the clarification. This just means that the 5V supply browns out, not the robotRIO's ability to read the digital inputs? I'm trying to figure out whether or not if we were to power the encoders another way, if that would fix it.

The bus switch that adjusts the signals passed to the FPGA is powered by a supply that is sourced by the buck-boost that powers the controller as a whole. That supply operates down to 4.5 V. That means that if you decide to power your encoder with a supply other than the one provided and the provided supply browns out, the signals will still make their way to the FPGA. As noted earlier, if your sensor depends on pull-up resistors (like limit switches or banner sensors or open-collector output encoders) then you will also need to add pull resistors connected to your external supply. You should be able to test this by either using the new power API to disable the 5 V supply manually or by installing a jumper between 5 V and Ground which puts the supply in protection.