2009/10/16 Peter Cauchy <nald...@gmail.com>: > pins: > opto-5v from usb > pulse-parallel port > dir-parallel port with or without 7406 ic in circuit.
One possibility that occurs to me is that the USB ground might not be the same as the parallel port ground. I can just about imagine them being capacitively coupled enough for step pulses to work, but not the effectively DC direction signal Do you have USB ground, parallel port ground and 7406 ground all explicitly connected? To change direction you need enough current to flow through the direction opto-coupler to light the internal LED. I was struggling with grasping this point myself last week. There needs to be a current path from your USB +5 to your USB 0V through the 7406 and the direction opto.coupler -- atp ------------------------------------------------------------------------------ Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
