CryptoCape Hookup Guide
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jbdatko, 
CaseyTheRobot 
Cape EEPROM
The Cape's EEPROM is defaulted to an I2C address of 0x57. If you plan on stacking capes -- the BeagleBone can support up to four stacked capes -- you may need to change the addresses of the EEPROM. The table below contains the available addresses for the EEPROM. Close the appropriate jumpers to change the address. (0 - Closed, 1 - Open).
Address Table
| A2 | A1 | A0 | 7-bit address |
|---|---|---|---|
| 1 | 0 | 0 | |
| 1 | 0 | 1 | |
| 1 | 1 | 0 | |
| 1 | 1 | 1 |
If you want to prevent users from writing to the EEPROM, you'll need to solder 0.1" male headers to the write protect pads and place a jumper on these pins. The EEPROM contains the cape definition, which is written during manufacturing and testing. If you overwrite it, the cape may not load correctly. You can always read the EEPROM with the following command:
sudo cat /sys/bus/i2c/devices/1-0057/eeprom| hexdump -C