Quote:
Originally Posted by Thad House
The RoboRIO internally does have a Buck/Boost internal to it. It stays powered down to about 4.5v. However, when it dips below 7v, the FPGA disables everything. So it would be a 100% software fix to lower the brownout voltage.
On our practice bot, we actually fed the RoboRIO straight from the regulated 12v. This is because it gets the voltage that is uses from Vin. So if you feed regulated voltage into the RoboRIO it never goes into brownout state. However, this is not FRC legal, and it is required by the rules to be fed straight from Vbatt.
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The second part is what I was suggesting as a solution to this issue. I'm well aware it's not legal, but a rule change could fix that fairly trivially.
I'd also disagree that it's a 100% software fix to lower voltage brownout, or, more accurately, that it should be fixed (And the 6.8-6.3 brownout on the 6V rails is more than likely hardware). To me the brownout is a feature meant to prevent controller shutdowns. While the 6.3V number may seem high, if you're drawing your battery down to 6.3V regularly it's not good and I'd rather have the control try to protect itself by disabling the large draws. Think of it as a soft failure. I'd rather have a soft failure than a dead robot.
To me, if I'm giving it voltage outside the input range then I'm not using the controller properly and any failures are my fault. The fact that the RoboRIO stays alive and tries to save itself as much as it does is nice.