Datasheet

264
32117D–AVR-01/12
AT32UC3C
The BOOTPROT fuses protects the following address space for the Boot Loader:
The SECURE fuses have the following functionality:
To erase or write a general-purpose fuse bit, the commands Write General-Purpose Fuse Bit
(WGPB) and Erase General-Purpose Fuse Bit (EGPB) are provided. Writing one of these com-
mands, together with the number of the fuse to write/erase, performs the desired operation.
An entire general-purpose fuse byte can be written at a time by using the Program GP Fuse
Byte (PGPFB) instruction. A PGPFB to GP fuse byte 2 is not allowed if the flash is locked by the
security bit. The PFB command is issued with a parameter in the PAGEN field:
• PAGEN[2:0] - byte to write
• PAGEN[10:3] - Fuse value to write
All general-purpose fuses can be erased by the Erase All General-Purpose fuses (EAGP) com-
mand. An EAGP command is not allowed if the flash is locked by the security bit.
Two errors can be detected in the FSR register after issuing these commands:
• Programming Error: A bad keyword and/or an invalid command have been written in the
FCMD register.
• Lock Error:
– A write or erase of the BOOTPROT or EPFL or UPROT fuse bits was attempted
while the flash is locked by the security bit.
– A write or erase of the SECURE fuse bits was attempted when SECURE mode was
enabled.
Table 15-3. Boot Loader Area Specified by BOOTPROT
BOOTPROT
Pages protected by
BOOTPROT
Size of protected
memory
7None 0
60-1 1kByte
50-3 2kByte
40-7 4kByte
3 0-15 8kByte
2 0-31 16kByte
1 0-63 32kByte
0 0-127 64kByte
Table 15-4. Secure state configuration
SECURE Functionality
00 Secure state disabled
01 Secure enabled, secure state debug enabled
10 Secure enabled, secure state debug disabled
11 Secure state disabled