Elemental I/O on LM3S8962 halts execution

[FiddlersElbow]

I'm using LabVIEW 2009, Embedded for ARM on the LM3S8962 evaluation board, and ran into issues with the predefined elemental I/O for the buttons - without elemental IO, everything works fine, but with any of the buttons, execution halts immediately with no error messages. Similar code worked perfectly on the original release of Embedded for ARM 1.0 & LabVIEW 8.5. I can no longer test with that version since the demo period has expired. I've tested this on 2 completely separate sets of hardware and Embedded for ARM 2009 installations, with the same issues in both. I've attached 2 snippets of simple working & non working VIs.

Stuart 

[NicB · Accepted solution]

Read the button once more - the port is also configured in the EIO node, so first read finds the port improperly configured.
Note that port configuration involves enabling a pull-up resistor and it takes some time until the input goes to the new configured state (it's not software, an RC time constant has the main role here).

Hope you don't mind for the "improved functionality".

[FiddlersElbow]

OK! That is what I was missing - I didn't realize that I needed to let EIO be read once before it would be useful. That solves the problem nicely. Nice update to the code - shows me exactly how to handle the EIO, and the rest is better than my solution would have been. I tweaked it a bit to finish the screensaver effect.

Thanks,

Stuart