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(2) System status register (SYS)
This register is allocated with status flags showing the operating state of the entire system. This register can
be read/written in 8- or 1-bit units.
7
6
SYS
0
0
Bit Position
Bit Name
4
PRERR
Protection Error Flag
Indicates that writing to a special register has not be executed in the correct sequence, and
protection error occurred.
Accumulate flag
0
UNLOCK
Unlock Status Flag
Read-only flag. Indicates the PLL unlock state. (For details, refer to 6.4 PLL Stabilization.)
Operation conditions of PRERR Flag
• Set conditions:
(PRERR = "1")
• Reset conditions:
(PRERR = "0")
CHAPTER 3 CPU FUNCTIONS
5
4
3
0
PRERR
0
0 : Protection error does not occur.
1 : Protection error occurs.
0 : Locked
1 : Unlocked
(1) If the store instruction most recently executed to peripheral I/O does not write
data to the PRCMD register, but to the specific register.
(2) If the first store instruction executed after the write operation to the
PRCMD register is to a peripheral I/O register other than the specific registers.
(1) When "0" is written to the PRERR flag of the SYS register.
(2) At system reset.
User's Manual U11969EJ3V0UM00
2
1
0
0
0
UNLOCK
FFFFF078H
Function
Address
After reset
0000000XB
79
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