mc9s08qg8 Freescale Semiconductor, Inc, mc9s08qg8 Datasheet - Page 53

• Manufacturer Part Number: mc9s08qg8
• Description: Hcs08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

1
4.7.3
4.7.4
During reset, the contents of the nonvolatile location NVPROT is copied from FLASH into FPROT. This
register can be read at any time, but user program writes have no meaning or effect.
Freescale Semiconductor
Background commands can be used to change the contents of these bits in FPROT.
KEYACC
Reset
Reset
Field
5
W
W
R
R
FLASH Configuration Register (FCNFG)
FLASH Protection Register (FPROT and NVPROT)
Enable Writing of Access Key — This bit enables writing of the backdoor comparison key. For more detailed
information about the backdoor key mechanism, refer to
0 Writes to 0xFFB0–0xFFB7 are interpreted as the start of a FLASH programming or erase command.
1 Writes to NVBACKKEY (0xFFB0–0xFFB7) are interpreted as comparison key writes.
0
0
7
7
= Unimplemented or Reserved
0
0
6
6
Figure 4-7. FLASH Configuration Register (FCNFG)
1
This register is loaded from nonvolatile location NVPROT during reset.
Figure 4-8. FLASH Protection Register (FPROT)
MC9S08QG8 and MC9S08QG4 Data Sheet, Rev. 1.01
Table 4-10. FCNFG Register Field Descriptions
SEC01:SEC00 changes to 1:0 after successful backdoor
key entry or a successful blank check of FLASH.
SEC01:SEC00
KEYACC
0
5
5
0:0
0:1
1:0
1:1
Table 4-9. Security States
FPS
0
0
4
4
(1)
Description
Section 4.6,
Description
unsecured
secure
secure
secure
3
0
0
3
1
Chapter 4 Memory Map and Register Definition
“Security.”
0
0
2
2
0
0
1
1
FPDIS
0
0
0
0
(1)
53