LMP92066_15 Datasheet, PDF (23/62 Pages) Texas Instruments – LMP92066 Dual Temperature-Controlled DAC with Integrated EEPROM and Output ON/OFF Control

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LMP92066
SNAS634A – MARCH 2014 – REVISED APRIL 2015
8.3.4.2 Access Control
By default, all operating memory locations are open to READ access. The WRITE access is controlled by the
Access Level setting. Increasing the Access Level, broadens the scope of the WRITE access. There are 3
access levels available to the user; see Access Control.
User can change the current Access Level by writing a “password” sequence to the ACC_CNTL register. The
“password” sequences are 2 consecutive I²C byte transfers to the ACC_CNTL register. The data content of each
2 byte transfer is unique for each access level.
For example, to enter access level L2 perform the following 2 transfers:
I²C OPERATION
WRITE
WRITE
READ
Table 4. Memory Access Control
REGISTER
ACC_CNTL
ACC_CNTL
ACC_CNTL
DATA
0xCD
0xF0
0x03
DESCRIPTION
First byte of the “password”.
Second byte of the “password”. After this transfer is
completed the access level is changed to L2.
Optional:
Reading the ACC_CNTL serves as status report.
The possible returned values are:
0x00 – access level L0
0x01 – access level L1 is activated
0x03 – access level L2 is activated (and due to
nesting, L1 is also indicated)
ACCESS LEVEL
L0
L1
L2
Table 5. EEPROM Access Levels
SCOPE
Default. User has READ access only to all locations in the operating
memory.
User has READ access to all locations, and WRITE access to ADR_LK
and BLK_CNTL registers.
User has READ and WRITE access to all operating memory locations.
NOTE
The access levels are nested. This means that L1 access level also gives all L0 level
functionality. L2 access level provides L1 and L0 functionality.
8.3.4.3 LUT, NOTEPAD Storage, and EEPROM
The LUT (its coefficients, BASE value, ALU control bits) and the NOTEPAD are stored in the operating memory
block spanning addresses 0x40 through 0x7F. This space is directly accessible (READ and WIRITE) via the I²C
bus.
There is an option to store the LUT and the NOTEPAD in the non-volatile memory, EEPROM. The move of data
from the operating memory to the EEPROM (BURN) is initiated by WRITING a command byte to the
EEPROM_CNTL register.
Upon power up the device automatically executes the TRANSFER of the EEPROM data to the operating
memory. The user can also issue a command via the I²C bus to force the TRANSFER of data from the EEPROM
to the operating memory.
TRANSFER/BURN
TRANSFER
BURN
I²C OPERATION
WRITE
WRITE
Table 6. EEPROM Control
REGISTER
DATA
EEPROM_CNTL
0x4E
EEPROM_CNTL
0xE4
COMMENT
Transfer of data from the EEPROM to the
operating memory.
Transfer of data from the operating memory
to the EEPROM.
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