3.1.1 Modifiable Configuration Zone Bytes
No bytes within the Configuration zone can be directly written because the Configuration zone is already locked. Several bytes can still be modified through the use of other commands.
SlotLocked Bits
For the ECC608-TFLXWPC, the
following individual slots may be uniquely configured to be
slot lockable or not: Slots 3-6 and 8-15. Through use of the Trust
Platform Design Suite tools, each of these slots may be set to either be fixed or
locked at the time of manufacturing. Slot group 10-12 and slot group 9, 13, 14 must
always be set the same way. If set to be lockable, the SlotLock mode of the
Lock
command can be used to lock a given slot. Each slot where
this feature is enabled can be individually locked just once. Once a slot is locked,
it can never be modified or unlocked but can still be used based on the access
policies defined for that slot.
Bytes 88 and 89 store the SlotLocked bytes. Initially, all bits in these bytes are set to a value of one. For those slots that are locked, the value of the respective bit will be set to a value of zero.
I2C Address Redefinition
UpdateExtra
command can be used to rewrite byte 85 of the
Configuration zone to a new I2C address. When this byte is set to a
nonzero value, the device configuration uses byte 85 as its I2C address
instead of the default address. Once this byte is rewritten, the device must be
powered-down or put into Sleep mode before this change takes effect.User Extra Byte
The UserExtra byte can be used for any desired purpose. This byte can only be updated
once with the UpdateExtra
command. The UserExtra byte is located at
byte 84 of the Configuration zone.
Counter[0,1]
While the counters are not used by this device, they are not disabled. If so desired, the monotonic counters may be used by the system. Note that the counters are initialized to zero and can count to the maximum value of 2,097,151. The counter value can be incremented or read through the use of theCounter
command. How this counter is used is strictly up to the system and independent of
anything else on the device. Counter values can be read or updated using the
Counter
command.