Datasheet

1195
32117D–AVR-01/12
AT32UC3C
39.2.2 SAB security restrictions
The Service Access bus can be restricted by internal security measures. A short description of
the security measures are found in the table below.
39.2.2.1 Security measure and control location
A security measure is a mechanism to either block or allow SAB access to a certain address or
address range. A security measure is enabled or disabled by one or several control signals. This
is called the control location for the security measure.
These security measures can be used to prevent an end user from reading out the code pro-
grammed in the flash, for instance.
Below follows a more in depth description of what locations are accessible when the security
measures are active.
HSB 0x5
Alternative mapping for HSB space, for compatibility with
other 32-bit AVR devices.
Memory Service
Unit
0x6 Memory Service Unit registers
Reserved Other Unused
Table 39-1. SAB Slaves, addresses and descriptions.
Slave Address [35:32] Description
Table 39-2. SAB Security Measures
Security Measure Control Location Description
Security bit
FLASHC
security bit set
Programming and debugging not possible, very restricted
access.
User code
programming
FLASHC
UPROT + security
bit set
Restricts all access except parts of the flash and the flash
controller for programming user code. Debugging is not
possible unless an OS running from the secure part of the
flash supports it.
Table 39-3. Security Bit SAB Restrictions
Name Address start Address end Access
OCD DCCPU,
OCD DCEMU,
OCD DCSR
0x100000110 0x100000118 Read/Write
User page 0x580800000 0x581000000 Read
Other accesses - - Blocked