Using a GPIO pin for both input and output.

[Shinigami2057]

Thanks a lot for the replies, Alan and oddjob. I had considered the use of two GPIO lines and tristate buffers to ensure that at least one of the lines was always disconnected, but as long as the single diode approach works without causing appreciable noise, I'll give it a shot.

Thanks for the code sample, oddjob! I'll report back on its success when it's implemented.

To the WPILib/FPGA guys:
I'd be nice to have the option bypass the FPGA completely and allow users to implement their own GPIO logic, for those willing to take the plunge.