Yes, I confirmed that it is ROM in the true silicone sense.... So I will look to see what I can do in hardware to get things moving... Will send a fix out to you all soon
Philip Rowse Electrical Engineering Department 3DRobotics Ballarat Australia > On 18 Jun 2014, at 18:44, Anuj Deshpande <[email protected]> wrote: > > 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.
