Micronas SDA 6000, User Manual

Page: 132 / 412

SDA 6000
PRELIMINARY DATA SHEET
Version 2.1
System Control & Configuration
6 - 12 Micronas
The following state diagram shows the state machine for security level switching and for
unlock command execution in low protected mode:
Figure 6-1 State Machine for Security Level Switching
Note:
1)
The new security level and password are valid, only if the security level
command register is accessed.
c_SCU is an abbreviation for “ write access to any SCU register ”, i.e. write access to any
of the following registers:
SYSCON1, SYSCON2, SCUSLC, SCUSLS, RP0H, XPERCON, WDT, WDTCON,
EXICON, EXISEL, ISNC, FOCON, SYSCON3
Note: The FOCON and SYSCON3 registers do not provide any function within the M2.
Nevertheless they are implemented in the system control unit of the embedded
microcontroller and write access to the associated addresses will influence the
state machine for security level switching.
Write Access in Low Protected Mode
The write access in low protected mode is also done via a command sequence. First the
specific command 4 (see
Figure 6-1 ) has to be written to register SCUSLC with the
current password. After this command, all security registers are unlocked until the next
write access to any SCU register is done. Read access is always possible to all registers
of the SCU and will not influence the command sequences. In register SCUSCS the
actual status of the command state machine can always be read.
It is recommended to use an atomic sequence for all command sequences.
UED11131
State 0
State 1 State 4
Command 0
Command 1
or any other SCU
Register Write Access
State 2
State 3
Command 2
Register Write Access
or any other SCU
Command 2
Register Write Access
or any other SCU
Command 3
1)
Command 1
and Low Protected Mode
Command 4
Any SCU
Register Write Access
Reset