ADUC7121 Analog Devices, ADUC7121 Datasheet - Page 36

• Manufacturer Part Number: ADUC7121
• Description: Precision Analog Microcontroller, 12-Bit Analog I/O, ARM7TDMI MCU
• Manufacturer: Analog Devices

Specifications of ADUC7121

• Mcu Core: ARM7 TDMI
• Mcu Speed (mips): 40
• Sram (bytes): 8192Bytes
• Gpio Pins: 32
• Adc # Channels: 9

ADuC7121
writing to the Flash/EE memory; each bit protects four pages, that
is, 2 kB. Write protection is activated for all access types. FEE1PRO
and FEE1HID similarly protect the second 64 kB block. All 32 bits
of this are used to protect four pages at a time.
Three Levels of Protection
Protection can be set and removed by writing directly into the
FEExHID MMR. This protection does not remain after reset.
Protection can be set by writing into the FEExPRO MMR. It
takes effect only after a save protection command (0x0C) and
a reset. The FEExPRO MMR is protected by a key to avoid direct
access. The key is saved one time only and must be reentered to
modify FEExPRO. A mass erase sets the key back to 0xFFFF but
also erases all the user code.
The Flash/EE memory can be permanently protected by using
the FEEPRO MMR and a particular value of the 0xDEADDEAD
key. Entering the key again to modify the FEExPRO register is
not allowed.
Sequence to Write the Key to Protection Registers
1.
2.
3.
4.
5.
To remove or modify the protection, the same sequence is used
with a modified value of FEExPRO. If the key chosen is the value
0xDEAD, then 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 shown in the following example;
this protects writing Page 4 to Page 7 of the Flash/EE memory:
FEE0PRO=0xFFFFFFFD; //Protect Page 4 to Page 7
FEE0MOD=0x48;
FEE0ADR=0x1234;
FEE0DAT=0x5678;
FEE0CON= 0x0C;
Follow the same sequence to permanently protect the part with
FEExADR = 0xDEAD and FEExDAT = 0xDEAD.
Write the bit in FEExPRO corresponding to the page to be
protected.
Enable key protection by setting Bit 6 of FEExMOD (Bit 5
must equal 0).
Write a 32-bit key in FEExADR, FEExDAT.
Run the write key command 0x0C in FEExCON; wait for
the read to be successful by monitoring FEExSTA.
Reset the part.
//Write key enable
//16-bit key value
//16-bit key value
//Write key command
Rev. 0 | Page 36 of 96
FLASH/EE CONTROL INTERFACE
FEE0DAT Register
FEE0DAT is a 16-bit data register.
Name:
Address:
Default value:
Access:
FEE0ADR Register
FEE0ADR is a 16-bit address register.
Name:
Address:
Default value:
Access:
FEE0SGN Register
FEE0SGN is a 24-bit code signature.
Name:
Address:
Default value:
Access:
FEE0PRO Register
FEE0PRO provides protection following subsequent reset MMR.
It requires a software key (see Table 41).
Name:
Address:
Default value:
Access:
FEE0HID Register
FEE0HID provides immediate protection MMR. It does not
require any software keys (see Table 41).
Name:
Address:
Default value:
Access:
FEE0DAT
0xFFFF0E0C
0xXXXX
Read and write
FEE0ADR
0xFFFF0E10
0x0000
Read and write
FEE0SGN
0xFFFF0E18
0xFFFFFF
Read only
FEE0PRO
0xFFFF0E1C
0x00000000
Read and write
FEE0HID
0xFFFF0E20
0xFFFFFFFF
Read and write.