HAL-APB-V1.5 Datasheet, PDF (42/59 Pages) Micronas – Application Board HAL-APB V1.x

HAL1820, HAL24xy, HAL28xy, HAL36xy, HAL38xy
Application Board HAL-APB V1.x
10.3. Locking of the Sensor
APPLICATION NOTE
A lock bit directly affects the sensor hardware:
1. Any further write access to the corresponding EEPROM area is blocked.
2. The EEPROM cells are permanently connected to their RAM layer.
If the lock bit C0LOC is not set the configuration of the DSP may be controlled by the
data stored in the RAM layer only. The customer must verify and (if necessary) refresh
the configuration data periodically.
Note: It is mandatory to lock the DSP CONIFIG EEPROM when the sensors are used
for qualification tests and in field applications.
If the lock bit C1LOC is not set the configuration of the LIN bus may be controlled by the
data stored in the RAM layer only. The customer must verify and (if necessary) refresh
the configuration data periodically.
Note: Micronas recommends to lock the COM CONFIG area when the sensors are
used for qualification tests and in field applications.
The lock bit does not restrict the read access to the memory. Any permitted address
can be read independent of the lock bit.
– Before setting a lock bit (C0LOC or C1LOC) verify the register contents of the corre-
sponding EEPROM area.
– Check for the effectiveness of the lock bit after locking.
This can be done by a write attempt to one of the EEPROM registers.
Note: The lock mechanism gets active with the next reset after setting the lock bit.
Once the lock mechanism is active the corresponding EEPROM area cannot be
reprogrammed. In particular the lock bits C0LOC, C1LOC, MLOC cannot be
cleared.
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Oct. 8, 2012; APN000055_003EN
Micronas