Hardware Reference Manual
UG-1262
Rev. B | Page 201 of 312
UPPER PAGE ADDRESS REGISTER
Address: 0x4001801C, Reset: 0x00000000, Name: PAGE_ADDR1
Write a byte address to this register to select the page in which that byte exists.
The selected page can be used for a sign command (selecting the end page for a block on which a signature is calculated). For commands
using both the PAGE_ADDR0 register and PAGE_ADDR1 register, ensure that PAGE_ADDR0 is always less than or equal to
PAGE_ADDR1, or else the command is denied.
Writing any address above the valid range of flash memory saturates the address register to prevent aliasing in the flash memory space.
Table 231. Bit Descriptions for PAGE_ADDR1
Bits Bit
Name Settings
Description
Reset
Access
[31:19] Reserved
Reserved.
0x0 R
[18:10]
VALUE
Upper Address Bits of the Page Address.
0x0
R/W
[9:0] Reserved
Reserved.
0x0
R
KEY REGISTER
Address: 0x40018020, Reset: 0x00000000, Name: KEY
When user code writes a key to access protected features, the key value must be written to this register.
Table 232. Bit descriptions for KEY
Bits Bit
Name
Settings Description
Reset
Access
[31:0] VALUE
Key Register. Unlock protected features by writing the appropriate key value to this
register.
0x0 W
0x676C7565
User key. Write this field with hexadecimal value of 0x676C7565 to enable certain
registers to be modified or to allow certain commands to be executed. This key is
used as a check to prevent accidental modification of settings or flash content. It is not a
security component and is not intended to be confidential information.
WRITE ABORT ADDRESS REGISTER
Address: 0x40018024, Reset: 0xXXXXXXXX, Name: WR_ABORT_ADDR
This register contains the address of a recently aborted write command. This address is only populated if the aborted write command
was started. If the command is aborted early enough to have no effect on the flash IP, this address is not updated.
Table 233. Bit Descriptions for WR_ABORT_ADDR
Bits Bit
Name
Settings
Description
Reset
Access
[31:0] VALUE
Hold Target Address. Holds the address targeted by an ongoing write command
and retains its value after an abort event. User code can read this register to
determine the flash locations affected by a write abort. The register value is
not guaranteed to persist after a new flash command is requested. Therefore,
read this value immediately following an aborted write.
0xXXXXXXXX R
WRITE PROTECTION REGISTER
Address: 0x40018028, Reset: 0xFFFFFFFF, Name: WRPROT
A user key is required to modify this register. This register can be automatically configured during device startup, in which case the
bootloader reads data from user space and loads that data into this register.
User code can affect nonvolatile write protection by writing to the appropriate location in the flash memory (see the Protection and
Integrity section). By default, the relevant location in flash is 0x3FFF0 (the fourth most significant word in user space) but can be
relocated by the Analog Devices bootloader.
Alternatively, user code can assert protection at run time for any unprotected blocks by directly writing this register. Blocks can have protection
added but cannot have protection removed, and changes are lost on reset. This approach is suggested especially during user code development.