Thanks Gerald. That is exactly the response I was expecting and exactly the feeling I had. Never really like playing Russian roulette myself. Do you see any issue with powering the sensors via a voltage regulator like http://www.pololu.com/product/2098 that can be turned on via a pin on the BBB once it is up and running?
On Thu, Mar 6, 2014 at 8:58 AM, Gerald Coley <ger...@beagleboard.org> wrote: > I put that in there for a reason. It may not happen all the time, but > eventually you could blow up the processor. > > Gerald > > > On Thu, Mar 6, 2014 at 8:56 AM, Matthew Witherwax <ablec...@gmail.com>wrote: > >> As part of the Control of Mobile Robotics class offered through Cousera, >> the students are building robots based around the BeagleBone Black. The >> robot has 5 infrared distance sensors and 2 reflectance sensors used for >> odometry. These sensors are connected via voltage dividers to pins 33, 35, >> 36, 37, 38, 39, and 49 of P9, and are powered from the same power supply >> used to power the BeagleBone Black. The System Manual has a rather >> explicit warning: >> >> NOTE: DO NOT APPLY VOLTAGE TO ANY I/O PIN WHEN POWER IS NOT SUPPLIED TO >> THE BOARD. IT WILL DAMAGE THE PROCESSOR AND VOID THE WARRANTY. >> NO PINS ARE TO BE DRIVEN UNTIL AFTER THE SYS_RESET LINE GOES HIGH. >> >> My concern is the current arrangement would allow the sensors to begin >> driving the pins before the SYS_RESET line goes high; however, I am a >> software guy just starting down the hardware path. Thus far many in the >> class have been using the robot without issue. Is my concern invalid? >> >> Thank you for your time. >> >> -- >> For more options, visit http://beagleboard.org/discuss >> --- >> You received this message because you are subscribed to the Google Groups >> "BeagleBoard" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to beagleboard+unsubscr...@googlegroups.com. >> >> For more options, visit https://groups.google.com/groups/opt_out. >> > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to a topic in the > Google Groups "BeagleBoard" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/beagleboard/_5Puwswy-RQ/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > beagleboard+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/groups/opt_out. > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
