Hardware Reference
In-Depth Information
Creating a cape EEPROM
If you have any semi-complicated hardware for the BeagleBone, you will benefit by adding
a cape-compatible EEPROM. The essential reference to populating the EEPROM is the
BeagleBone SRM's section on
Cape Board Support
. This section contains the EEPROM
format. To jumpstart your EEPROM file creation, you can use a tool called the
EEPROM
cape generator
available at:
https://github.com/picoflamingo/BBCape_EEPROM
. This
tool with its simple command-line interface will provide the skeleton for your cape
EEPROM. Currently, it does not completely implement the cape specification, so you must
use a binary editor to set the remaining values of the EEPROM. The process to create the
EEPROM binary involves reading through the SRM and writing the appropriate values, at
the correct offsets, in a binary file.
You can view the CryptoCape's EEPROM by executing the following command as root:
cat /sys/bus/i2c/devices/1-0057/eeprom | hexdump -C
By default, the CryptoCape EEPROM is located at address 0x57 on the I2C bus. If you
have multiple capes, you can change the address of the CryptoCape EEPROM by placing a
solder jumper or solder
blob
on the A0 or A1 address pads next to the EEPROM. The res-
ults of reading the EEPROM with the previous command will produce the following:
00000000 aa 55 33 ee 41 31 42 42 2d 42 4f 4e 45 2d 43
52
|.U3.A1BB-BONE-CR|
00000010 59 50 54 4f 00 00 00 00 00 00 00 00 00 00 00 00
|YPTO............|
00000020 00 00 00 00 00 00 30 30 41 30 53 70 61 72 6b 46
|......00A0SparkF|
00000030 75 6e 00 00 00 00 00 00 00 00 42 42 2d 42 4f 4e
|un........BB-BON|
00000040 45 2d 43 52 59 50 54 4f 00 00 00 11 32 30 31 34
|E-CRYPTO....2014|
00000050 30 30 30 30 30 30 30 30 00 00 00 00 00 00 00 00
|00000000........|
00000060 00 00 00 00 00 00 00 00 00 00 e0 73 e0 73 00 00
|...........s.s..|
00000070 00 00 00 00 00 00 00 00 00 00 00 00 a0 26 c0 06
|.............&..|
