ADUC7023BCPZ62I Datasheet, PDF (38/96 Pages) Analog Devices – Precision Analog Microcontroller, 12-Bit Analog I/O, ARM7TDMI MCU with Enhanced IRQ Handler

ADuC7023
Data Sheet
SECURITY
The 62 kB of Flash/EE memory available to the user can be read
and write protected.
Bit 31 of the FEEPRO/FEEHIDE MMR (see Table 34) protects
the 62 kB from being read through JTAG programming mode.
The other 31 bits of this register protect writing to the flash
memory. Each bit protects four pages, that is, 2 kB. Write
protection is activated for all types of access.
Three Levels of Protection
Protection can be set and removed by writing directly into
FEEHIDE MMR. This protection does not remain after reset.
Protection can be set by writing into FEEPRO MMR. It only
takes effect after a save protection command (0x0C) and a reset.
The FEEPRO MMR is protected by a key to avoid direct access.
The key is saved once and must be entered again to modify
FEEPRO. A mass erase sets the key back to 0xFFFF but also
erases all the user code.
Flash can be permanently protected by using the FEEPRO
MMR and a particular value of key: 0xDEADDEAD. Entering
the key again to modify the FEEPRO register is not allowed.
Sequence to Write the Key
1. Write the bit in FEEPRO corresponding to the page to be
protected.
2. Enable key protection by setting Bit 6 of FEEMOD (Bit 5
must equal 0).
3. Write a 32-bit key in FEEADR, FEEDAT.
4. Run the write key command 0x0C in FEECON; wait for
the read to be successful by monitoring FEESTA.
5. Reset the part.
To remove or modify the protection, the same sequence is used
with a modified value of FEEPRO. If the key chosen is the value
0xDEAD, the memory protection cannot be removed. Only a mass
erase unprotects the part, but it also erases all user code.
The sequence to write the key is illustrated in the following
example (this protects writing Page 4 to Page 7 of the Flash):
FEEPRO=0xFFFFFFFD; //Protect Page 4 to
Page 7
FEEMOD=0x48; //Write key enable
FEEADR=0x1234;
//16 bit key value
FEEDAT=0x5678;
//16 bit key value
FEECON= 0x0C;
//Write key command
The same sequence should be followed to
protect the part permanently with FEEADR =
0xDEAD and FEEDAT = 0xDEAD.
FLASH/EE CONTROL INTERFACE
Serial and JTAG programming use the Flash/EE control interface,
which includes the eight MMRs outlined in this section.
FEESTA Register
Name:
FEESTA
Address:
0xFFFFF800
Default value: 0x20
Access:
Read
Function:
FEESTA is a read-only register that reflects the
status of the flash control interface as
described in Table 31.
Table 31. FEESTA MMR Bit Designations
Bit
Description
7 to 6 Reserved.
5
Reserved.
4
Reserved.
3
Flash interrupt status bit.
This bit is set automatically when an interrupt occurs, that is, when a command is complete and the Flash/EE interrupt enable bit
in the FEEMOD register is set.
This bit is cleared when reading FEESTA register.
2
Flash/EE controller busy.
This bit is set automatically when the controller is busy.
This bit is cleared automatically when the controller is not busy.
1
Command fail.
This bit is set automatically when a command is not completed.
This bit is cleared automatically when reading FEESTA register.
0
Command pass.
This bit is set by the MicroConverter when a command is completed.
This bit is cleared automatically when reading the FEESTA register.
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