Correct. These are the boot pins and will affect the booting process. This is not a damage issue as defined by driving pins to create damage to the processor.
Leave the boot pins alone until after reset is released. Do not drive the other pins until after 3.3V is up or the Reset signal is released. Gerald On Thu, Oct 16, 2014 at 3:25 PM, Robert Nelson <[email protected]> wrote: > On Thu, Oct 16, 2014 at 3:17 PM, Britton Kerin <[email protected]> > wrote: > > The SRM contains the following conflicting information: > > > > The System Reference Manual (SRM) says you're supposed to gate all GPIO > > (and other inputs) such that they aren't driven until either the > SYS_RESET > > line goes high (according to SRM section 7.1, 8.0, and possibly others) > or > > until the VDD_3V3B rail is up (according to SRM 8.6.2). Are these > conditions > > identical in practice? If not which is the right one? > > > > Also, the reference manual section 8.3.1 says this: > > > > If you plan to use any of these signals, then on power up, these > pins > > should not be driven. If you do, it can affect the boot mode of the > > processor and could keep the processor from booting or working > correctly. > > > > while not wrong this paragraph is going to create a dangerous wrong > impression > > for most readers: that the boot pins are special and are the ones you > have to > > worry about driving early. I think it would be good to change this > paragraph > > or add a pointer to the other warnings that apply to all pins or > something. > > Those pins control the bootrom's boot selection. If you drive them the > wrong way after sys_reset you can change the processor to boot from an > interface that isn't enable/setup/etc... > > Regards, > > -- > Robert Nelson > http://www.rcn-ee.com/ > > -- > 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 [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- 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 [email protected]. For more options, visit https://groups.google.com/d/optout.
