On Monday, September 7, 2015 at 6:52:12 PM UTC-6, Graham wrote: > > Well, by definition, the boot programming pins are going to have the > pull-ups / pull-downs, so you know what they are going to be doing, until > over-ridden. > > Most processors start up with the programmable pins as inputs, then move > to the configured state. >
If it were so... but it seems with such an abundance of modes and pins, a number of the pins I am using are in a variety if input, output, hi-Z and I/O defaults at powerup, most often with pullup or pull-downs. The good news is, I've added enough gating and the additional fast-starting Vdd to avoid conflicts. SPI attached peripherals (powered early) all need commands shifted in to drive outputs, so that's safe too. Now for the *next* Beaglebone, innocuous I/Os would be a great feature... Anything else can be dangerous to the pins. But, as Charles says, RTFM. > > If you are concerned, use the bus-isolation /transmission-gate chips, > power them early, supply your own pull-ups/pull-downs, and switch the > connection on when SYS_RESETn goes high. Then you are unconditionally > safe, and in-control. > > --- Graham > Thanks, Mike -- 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/d/optout.
