Protection Unlock Register (Fpr); Protection Unlock Status Register (Fpsr) - Renesas RX100 Series User Manual

RX13T Group
31.4.3

Protection Unlock Register (FPR)

Address(es): FLASH.FPR 007F C0C0h
b7 b6
x x
Value after reset:
x: Undefined
This write-only register is used to protect the FPMCR register from being rewritten inadvertently when the CPU runs out
of control. Writing to the FPMCR register is enabled only when the following procedure is used to access the register.
Procedure to unlock protection
(1) Write A5h to the FPR register.
(2) Write a set value to the FPMCR register.
(3) Write the inverted set value to the FPMCR register.
(4) Write a set value to the FPMCR register again.
When a procedure other than the above is used to write data, the FPSR.PERR flag is set to 1.
31.4.4

Protection Unlock Status Register (FPSR)

Address(es): FLASH.FPSR 007F C0C1h
b7 b6
— —
Value after reset: 0 0
Bit Symbol Bit Name
b0 PERR Protect Error Flag
b7 to b1 — Reserved
PERR Flag (Protect Error Flag)
When the FPMCR register is not accessed as described in the procedure to unlock protection, data is not written to the
register and this flag is set to 1.
[Setting condition]
 The FPMCR register is not accessed as described in the procedure to unlock protection.
[Clearing condition]
 The FPMCR register is accessed according to the procedure to unlock protection described in section 31.4.3,
Protection Unlock Register (FPR) .
R01UH0822EJ0100 Rev.1.00
Jul 31, 2019
b5 b4 b3 b2
x x x x
b5 b4 b3 b2
— — — —
0 0 0 0
Description
0: No error
1: An error occurs.
These bits are read as 0.
b1 b0
x x
b1 b0
— PERR
0 0
31. Flash Memory (FLASH)
R/W
R
R
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