ATSHA204(2012) Ver la hoja de datos (PDF) - Atmel Corporation
Número de pieza
componentes Descripción
Fabricante
ATSHA204 Datasheet PDF : 65 Pages
| |||
2.1.2.1 Configuration Zone Locking
Certain bytes within the configuration zone cannot be modified, regardless of the state of LockConfig. Access to the remainder
of the bytes within the zone is controlled using the LockValue byte in the configuration zone, as shown in the following table.
Throughout this document, if LockConfig is 0x55, the configuration zone is said to be unlocked; otherwise it is locked.
Table 2-6. Configuration Zone Locking
LockValue == 0x55 (unlocked)
LockValue != 0x55 (locked)
Read Access
Read
Read
Write Access
Write
<never>
2.1.2.2 Data Zone Locking
Throughout this document, if LockValue is 0x55, then both the OTP and data zones are said to be unlocked; otherwise they
are locked.
Note:
There is neither read nor write access to the OTP and data zones prior to locking of the configuration zone.
Table 2-7. Data zone access restrictions
LockValue == 0x55 (unlocked)
LockValue != 0x55 (locked)
Read Access
<never>
Read
Write Access
Write
Write**
2.1.2.3 OTP Zone Locking
Reads and writes of the OTP zone depend on the state of the LockConfig, LockValue, and OTPmode bytes in the
configuration zone. See Section 2.1.3 for more information.
2.1.3
One Time Programmable (OTP) Zone
This zone of 64 bytes (512 bits) is part of the EEPROM array, and can be used for read-only storage or consumption logging
purposes.
Prior to locking the configuration section (using lockConfig), the OTP zone is inaccessible and can be neither read nor written.
After configuration locking, but prior to locking of the OTP zone (using lockValue), the entire OTP zone can be written using
the Write command. If desired, the data to be written can be encrypted. When unlocked, this zone cannot be read at all.
Once the OTP zone is locked, the OTPmode byte in the configuration zone controls the permissions of this zone, as follows:
• Read-only Mode
In this mode, the data cannot be modified, and would be used to store fixed model numbers, calibration information,
manufacturing history, or other data that should never change. The Write command will always return an error and
leave the memory unmodified.
All 64 bytes within the OTP section are always available for reading using either 4- or 32-byte reads.
• Consumption Mode
This mode is not currently supported. Contact Atmel for further information.
• Legacy Mode
In this mode, the operation of the OTP zone is consistent the fuse array on the Atmel ATSA102S. Reads of words
zero and one are always prohibited, while reads of the remaining 14 words are always permitted. Only 32-bit reads
are permitted, and any attempt to execute a 256-bit read will result in an error return code. All write operations to the
OTP zone are prohibited. See Section 9 or more of the Atmel ATSA102S compatibility details.
All OTP zone bits have a value of one on shipment from the Atmel factory.
Atmel ATSHA204 [DATASHEET] 10
8740D−CRYPTO−3/12
Share Link: 