On Tue, May 26, 2015 at 1:34 PM, Adam Lee <[email protected]> wrote: > Hello, I noticed the magic number "0xEE3355AA" at the offset[0:4] in the > eeprom of Beaglebone. > What is the purpose of this data? Is it merely to tell if the board ID > structure has been tempered?
U-boot uses it to identify the board as a BeagleBone. In particular, if you look in the source here: http://git.denx.de/?p=u-boot.git;a=blob;f=board/ti/am335x/board.c;h=0739e6021a21e71d7d0f5c840b793ce7fdf98fae;hb=f33cdaa4c3da4a8fd35aa2f9a3172f31cc887b35#l63 You'll see where the header is read. This says that we can likely trust the contents of the EEPROM to tell us the type of board. The idea here is that people might want to use BeagleBone as a reference to make their own boards. This makes it relatively easy. If you use your own u-boot, you can simply remove the EEPROM, but we try to use the same source and binary as a bunch of other similar boards. This binary compatibility allows for bootable SD card images to be shared between such boards. We left a bunch of room in the EEPROM for potentially storing a bunch of other configuration information. So far, not there hasn't been any consolidated and compelling suggestions for its use. Personally, I wanted a configuration tool to store some info for boot, but defining the format and authoring tool has proven difficult for now. So, you can use it as you wish. > > -- > 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.
