MC9S08DZ128 Datasheet, PDF (79/458 Pages) Freescale Semiconductor, Inc – Microcontrollers

Chapter 4 Memory
Table 4-15. FOPT Register Field Descriptions
Field
Description
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 4-16. 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 4.6.9, “Security.”
Table 4-16. 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.
4.6.11.3 FLASH and EEPROM Configuration Register (FCNFG)
7
6
5
4
3
2
1
0
R
0
1
0
0
0
1
EPGSEL KEYACC
W
Reset
0
0
0
1
0
0
0
1
= Unimplemented or Reserved
Figure 4-16. FLASH and EEPROM Configuration Register (FCNFG)
Table 4-17. FCNFG Register Field Descriptions
Field
Description
6
EPGSEL
5
KEYACC
EEPROM Page Select — This bit selects which EEPROM page is accessed in the memory map.
0 Page 0 is in foreground of memory map. Page 1 is in background and can not be accessed.
1 Page 1 is in foreground of memory map. Page 0 is in background and can not be accessed.
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 Section 4.6.9, “Security.”
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.
MC9S08DZ128 Series Data Sheet, Rev. 1
Freescale Semiconductor
79