MC9S08DZ60CLH Datasheet, PDF (63/416 Pages) Freescale Semiconductor, Inc – MC9S08DZ60 Series Features

Chapter 4 Memory
R
W
Reset
7
KEYEN
F
6
5
4
3
2
1
0
FNORED EPGMOD
0
0
0
SEC
F
F
0
0
0
F
F
= Unimplemented or Reserved
F = loaded from nonvolatile location NVOPT during reset
Figure 4-6. Flash and EEPROM Options Register (FOPT)
Table 4-9. FOPT Register Field Descriptions
Field
Description
7
KEYEN
Backdoor Key Mechanism Enable — When this bit is 0, the backdoor key mechanism cannot be used to
disengage security. The backdoor key mechanism is accessible only from user (secured) firmware. BDM
commands cannot be used to write key comparison values that would unlock the backdoor key. For more detailed
information about the backdoor key mechanism, refer to Section 4.5.9, “Security.”
0 No backdoor key access allowed.
1 If user firmware writes an 8-byte value that matches the nonvolatile backdoor key (NVBACKKEY through
NVBACKKEY+7 in that order), security is temporarily disengaged until the next MCU reset.
6
FNORED
Vector Redirection Disable — When this bit is 1, then vector redirection is disabled.
0 Vector redirection enabled.
1 Vector redirection disabled.
5
EPGMOD
EEPROM Sector Mode — When this bit is 0, each sector is split into two pages (4-byte mode). When this bit is
1, each sector is in a single page (8-byte mode).
0 Half of each EEPROM sector is in Page 0 and the other half is in Page 1.
1 Each sector is in a single page.
1:0
SEC
Security State Code — This 2-bit field determines the security state of the MCU as shown in Table 4-10. When
the MCU is secure, the contents of RAM, EEPROM and Flash memory cannot be accessed by instructions from
any unsecured source including the background debug interface. SEC changes to 1:0 after successful backdoor
key entry or a successful blank check of Flash. For more detailed information about security, refer to Section
4.5.9, “Security.”
Table 4-10. Security States¹
SEC[1:0]
Description
0:0
secure
0:1
secure
1:0
unsecured
1:1
secure
1 _{SEC changes to 1:0 after successful backdoor key entry}
or a successful blank check of Flash.
MC9S08DZ60 Series Data Sheet, Rev. 4
Freescale Semiconductor
63