Cc'd to the BBB group as well Where can we fond the code to the Boot Rom? For the next revision of our cape, I will be fixing the enable, I am aware of this, the power too the level shifters was to be enabled via the SYS_RESETN, but it has caused other issues, so now it is hard connected via a jumper.
There are only a few of these capes for development purposes, so we would like to modify the ROM to allow for this on these capes. There will be further changes to revision 2 of the cape, but before that, I need to allow development to continue, regardless of hardware issues For this application, being an autopilot, we are going for a fixed configuration, so we do not have any unexpected behaviour during flight, due to user configuration changes. Thanks Philip > On 16 Jun 2014, at 20:22, Jason Kridner <[email protected]> wrote: > > On Mon, Jun 16, 2014 at 10:37 PM, Anuj Deshpande > <[email protected]> wrote: >> That's indeed right. The first stage one is called MLO it seems >> http://wiki.beyondlogic.org/index.php/BeagleBoneBlack_Boot_Process >> >> >> >> On Tue, Jun 17, 2014 at 8:04 AM, Andrew Tridgell <[email protected]> >> wrote: >>> >>> Hi Anuj, >>> >>>> Check the link >>>> https://github.com/beagleboard/U-boot >>> >>> I may be wrong, but my impression is that U-Boot is a 2nd stage >>> bootloader, and there is a first stage that selects boot media and loads >>> U-Boot. My suspicion is it is the first stage that is failing, probably >>> due to the first stage looking at pin values changed by the cape that >>> change the selection of available boot media. If that is wrong please >>> let me know. > > Before MLO is the ROM bootloader. It looks at the boot pins. > > See > https://github.com/CircuitCo/BeagleBone-Black/blob/master/BBB_SRM.pdf?raw=true > pages 34, 97 and 106. The SYSBOOT signals are detailed in > http://www.ti.com/lit/ug/spruh73j/spruh73j.pdf on Table 26-7. > > You want to avoid pulling these before SYS_RESETN goes high, just like > the SRM says. > >>> >>> I haven't found a doc that explains the early stage boot process, if you >>> found one that would be very helpful. >>> >>> Cheers, Tridge >> -- 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.
