mc9s12vr48 Freescale Semiconductor, Inc, mc9s12vr48 Datasheet - Page 468

• Manufacturer Part Number: mc9s12vr48
• Description: S12 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

64 KByte Flash Module (S12FTMRG64K512V1)
1
All bits in the FSEC register are readable but not writable.
During the reset sequence, the FSEC register is loaded with the contents of the Flash security byte in the
Flash configuration field at global address 0x3_FF0F located in P-Flash memory (see
indicated by reset condition F in
phrase containing the Flash security byte during the reset sequence, all bits in the FSEC register will be
set to leave the Flash module in a secured state with backdoor key access disabled.
468
KEYEN[1:0]
Loaded from IFR Flash configuration field, during reset sequence.
RNV[5:2]
SEC[1:0]
Offset Module Base + 0x0001
Reset
Field
7–6
5–2
1–0
W
R
Backdoor Key Security Enable Bits — The KEYEN[1:0] bits define the enabling of backdoor key access to the
Flash module as shown in
Reserved Nonvolatile Bits — The RNV bits should remain in the erased state for future enhancements.
Flash Security Bits — The SEC[1:0] bits define the security state of the MCU as shown in
Flash module is unsecured using backdoor key access, the SEC bits are forced to 10.
F
7
1
KEYEN[1:0]
= Unimplemented or Reserved
F
6
1
1
1
Preferred KEYEN state to disable backdoor key access.
Preferred SEC state to set MCU to secured state.
KEYEN[1:0]
SEC[1:0]
Figure 17-5. Flash Security Register (FSEC)
MC9S12VR Family Reference Manual,
00
01
10
11
00
01
10
11
Preliminary - Subject to Change Without Notice
Figure
Table
Table 17-8. FSEC Field Descriptions
Table 17-10. Flash Security States
Table 17-9. Flash KEYEN States
F
5
1
17-9.
17-5. If a double bit fault is detected while reading the P-Flash
Status of Backdoor Key Access
F
4
1
Status of Security
RNV[5:2]
Description
UNSECURED
DISABLED
SECURED
DISABLED
DISABLED
SECURED
SECURED
ENABLED
F
3
1
1
1
Rev. 2.2
F
2
1
Freescale Semiconductor
F
Table
1
1
Table
SEC[1:0]
17-3) as
17-10. If the
F
0
1