Thank everyone for the advice. Following the advice, I added a larger pullup but that did not change the behavior. I also switched the E-Stop button from making a connection to ground to breaking a connection from ground. That also did not change the behavior.
I did finally figure out what was causing the problem. It appears that on this motherboard which uses a sis755 chipset, accessing the onboard serial port while using the 7i43 connected to the onboard parallel port makes the 7i43 do strange things like have square waves appear on the input pins. I'm pretty sure it's a problem with the sis755 chipset since I can't see why accessing the serial port would affect the parallel port. I installed a usb serial port and hooked the arduino up to that and everything is running just fine now with no more strange square waves on all of the unused input pins. Lawrence On 20 February 2010 05:39, Flying Electron <[email protected]> wrote: > > > Hi, > > > > I was using one of the inputs to read my E-STOP button which shorts to > > ground when triggered, but I kept on getting false positives. I looked > > at the input pin in halscope and saw a square wave that goes high for > > 2ms then low for 2ms and repeats. I removed the E-Stop button and > > everything else connected to the IO of the 7i43 so it is just the > > parallel port and the usb cable powering the 7i43 connected. Looked in > > halscope again, and the square wave is still there with nothing > > connected. Checked several other unassigned pins and they also show the > > square wave. Anyone have any ideas on what is happening? > > > > Thanks! > > > > Lawrence > > > > > > > ------------------------------------------------------------------------------ > > Download Intel® Parallel Studio Eval > > Try the new software tools for yourself. Speed compiling, find bugs > > proactively, and fine-tune applications for parallel performance. > > See why Intel Parallel Studio got high marks during beta. > > http://p.sf.net/sfu/intel-sw-dev > > _______________________________________________ > > Emc-users mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > ------------------------------------------------------------------------------ > Download Intel® Parallel Studio Eval > Try the new software tools for yourself. Speed compiling, find bugs > proactively, and fine-tune applications for parallel performance. > See why Intel Parallel Studio got high marks during beta. > http://p.sf.net/sfu/intel-sw-dev > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
