Hi All i read up on the ROM boot code, and it's masked. we can't make changes to it at all. http://tara.mmto.org/computers/beagle/uboot.html we have the address, etc. of the place where the ROM boot loader is, but we won't be able to make changes to it. also, this discussion on the ti forum http://e2e.ti.com/support/arm/sitara_arm/f/791/t/158347.aspx so ROM -> MLO -> U-Boot. and only the last 2 can be edited.
On Tue, Jun 17, 2014 at 7:49 PM, Philip Rowse <[email protected]> wrote: > 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.
