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Protection
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SPRUH91D–March 2013–Revised September 2016
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System Configuration (SYSCFG) Module
10.2.1 Requirements to Access SYSCFG Registers
As mentioned previously, the SYSCFG module controls several global operations of the device; therefore,
it has protection mechanism that prevents spurious and illegal accesses to the registers in its memory
map. The protection mechanism enables accesses to these registers only if certain conditions are met.
The protection mechanisms that are present in the module are described in the following sections.
10.2.1.1 Privilege Mode Protection
The CPU supports two privilege levels: Supervisor and User. Several registers in the SYSCFG memory-
map can only be accessed when the accessing host (CPU or master peripheral) is operating in privileged
mode, that is, in Supervisor mode. The registers that can only be accessed in privileged mode are listed in
Section 10.5. See the TMS320C674x DSP CPU and Instruction Set Reference Guide (SPRUFE8) for
details on privilege levels.
10.2.1.2 Kicker Mechanism Protection
NOTE: The Kick 0 and Kick 1 registers can only be accessed in privileged mode (the host needs to
be in Supervisor mode). Any number of accesses may be performed to the SYSCFG
module, while the module is unlocked.
The SYSCFG module remains unlocked after the unlock sequence, until locked again.
Locking the module is accomplished by writing any value other then the key values to either
KICK0 or KICK1.
To access any registers in the SYSCFG module, it is required to follow a special sequence of writes to the
Kick registers (Kick0 and Kick1) with correct key values. Writing the correct key value to the kick registers
unlocks the registers in the SYSCFG memory-map. In order to access the SYSCFG registers, the
following unlock sequence needs to be executed in software:
1. Write the key value of 83E7 0B13h to Kick 0 register.
2. Write the key value of 95A4 F1E0h to Kick 1 register.
After steps 1 and 2, the SYSCFG module registers are accessible and can be configured as per the
application requirements.
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