On 03/14/2010 10:44 PM, Ben Gamari wrote: > > When measuring the SIMO signal on the expansion connector with my daughterboard > connected, I noticed that the daughterboard's level shifter appeared to be > driving the signal higher than it should, to ~2.9 Volts. I then checked the > 1.8V rail voltage and found that it too was higher than expected, again at 2.9 > volts. When I unplug the daughterboard, the 1.8V rail voltage returns to its > expected value. > > I'm both perplexed and concerned with this behavior. I completely fail to > see how my board is raising the voltage on the 1.8V rail (schematic available > at [3]). While the BeagleBoard seems quite stable, I'm very concerned that > perhaps the daughterboard over-drove the SIMO ball and burned out some subset > of the OMAP. Regardless, as mentioned earlier, I have verified the > functionality of the same ball as a GPIO input. Thus, I am thoroughly confused. > Is it possible that the ball's GPIO receiver could remain functional while the > McSPI receiver is burned out? > > [3] http://goldnerlab.physics.umass.edu/git?p=tracker-board.git;a=summary I'd be happy to check your circuit for you, if it were posted in a more widely used format. How about a PDF of the schematic. -- Ned Forrester nforrester@xxxxxxxx Oceanographic Systems Lab 508-289-2226 Applied Ocean Physics and Engineering Dept. Woods Hole Oceanographic Institution Woods Hole, MA 02543, USA http://www.whoi.edu/ http://www.whoi.edu/sbl/liteSite.do?litesiteid=7212 http://www.whoi.edu/hpb/Site.do?id=1532 http://www.whoi.edu/page.do?pid=10079 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
