aduc7033bstz-8l-rl Analog Devices, Inc., aduc7033bstz-8l-rl Datasheet - Page 32

• Manufacturer Part Number: aduc7033bstz-8l-rl
• Description: Integrated Precision Battery Sensor For Automotive
• Manufacturer: Analog Devices, Inc.

ADuC7033
In summary, there are three levels of protection.
Temporary Protection
Set and remove temporary protection by writing directly into
the FEExHID MMR. This register is volatile and therefore
protection is only in place while the part remains powered on.
This protection is not reloaded after a power cycle.
Keyed Permanent Protection
Set keyed permanent protection via FEExPRO to lock the
protection configuration. The software key used at the start of
the required FEExPRO write sequence is saved one time only
and thereafter must be used for any subsequent access of the
FEExHID or FEExPRO MMRs. A mass erase resets the key to
0xFFFF but also erases the entire user code space.
Sequence Example
The sequence to write the key and set permanent protection is illustrated in the following example; this protects writing Page 4 and Page 5
of the Flash/EE memory:
Int a = FEExSTA;
FEExPRO = 0xFFFFFFFB;
FEExADR = 0x66BB;
FEExDAT = 0xAA55;
FEExMOD = 0x0048;
FEExCON = 0x0C;
while (FEExSTA & 0x04){}
//Ensure FEExSTA is cleared
//Protect Pages[4:5]
//32 bit key value (Bits[31:16])
//32 bit key value (Bits[15:0])
//Lock security sequence
//Write key command
//Wait for command to finish
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Permanent Protection
Set permanent protection via FEExPRO, similarly to keyed
permanent protection, the only difference is that the Software
Key 0xDEADDEAD is used. Once the FEExPRO write
sequence is saved, only a mass erase resets the key to
0xFFFFFFFF. This also erases the entire user code space.
Sequence to Write the Key and Set Permanent Protection
1.
2.
3.
4.
To remove or modify the protection, the same sequence can be
used with a modified value of FEExPRO.
Write in FEExPRO corresponding to the pages to be
protected.
Write the new (user defined) 32-bit key in FEExADR
(Bits[31:16]) and FEExDAT (Bits[15:0]).
Write 1, 0 in FEExMOD[6:5] and set FEExMOD[3].
Run the Write Key Command 0x0C in FEExCON.