On Sun, Jul 9, 2017 at 2:46 PM, <[email protected]> wrote: > Hi Guys, > > Lurker here. I have been working on developing audio capes for the > Beaglebone Black. I now have a design I am poised to ship. First, however, > I need to know the right thing to do with the cape's EEPROM so it works "out > of the box" for users. > > I believe the EEPROM is read by the BBB during boot, and the info in the > EEPROM helps the BBB load the correct device tree overlay, right?
Correct, we do it in u-boot now: http://elinux.org/Beagleboard:BeagleBoneBlack_Debian#U-Boot_Overlays > > Can one of the experts on this list please point me to a HOWTO or other > documentation which describes how to put the correct ID into the EEPROM so > the BBB knows what to do with the associated cape? Some info about where to > stage the cape's .dtbo file so it is loaded during boot would also be > appreciated. Here's one example eeprom: TI: DLPDLCR2000 Overlay: https://github.com/beagleboard/bb.org-overlays/blob/master/src/arm/DLPDLCR2000-00A0.dts it's eeprom: https://github.com/RobertCNelson/boot-scripts/blob/master/device/bone/capes/DLPDLCR2000/eeprom.dump voodoo@hestia:/opt/github/boot-scripts/device/bone/capes/DLPDLCR2000$ hexdump -C eeprom.dump 00000000 aa 55 33 ee 41 31 44 4c 50 44 4c 43 52 32 30 30 |.U3.A1DLPDLCR200| 00000010 30 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |0...............| 00000020 00 00 00 00 00 00 30 30 41 30 54 49 00 00 00 04 |......00A0TI....| 00000030 00 00 00 00 00 00 00 00 00 00 44 4c 50 44 4c 43 |..........DLPDLC| 00000040 52 32 30 30 30 00 00 00 00 00 31 32 33 34 35 36 |R2000.....123456| 00000050 37 38 39 30 31 32 33 34 00 00 00 00 00 00 00 00 |78901234........| 00000060 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 000000f4 the eeprom stuct: https://github.com/RobertCNelson/Bootloader-Builder/blob/2bcb643912c2bd24fb6fa0770219b9cfc2c096a6/patches/v2017.07-rc3/0002-U-Boot-BeagleBone-Cape-Manager.patch#L436-L449 You can see how u-boot disables the hdmi video/audio: https://github.com/RobertCNelson/Bootloader-Builder/blob/2bcb643912c2bd24fb6fa0770219b9cfc2c096a6/patches/v2017.07-rc3/0002-U-Boot-BeagleBone-Cape-Manager.patch#L257-L261 Regards, -- Robert Nelson https://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]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CAOCHtYi8djtWxvSuUncD389gMHvkS2qmpwu9CMP6uNX7Q7X35A%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
