Datasheet

Chapter 4 Memory
MC9S08AW60 Data Sheet, Rev 2
60 Freescale Semiconductor
SEC01:SEC00 changes to 1:0 after successful backdoor key entry or a successful blank check of FLASH.
4.6.3 FLASH Configuration Register (FCNFG)
Bits 7 through 5 may be read or written at any time. Bits 4 through 0 always read 0 and cannot be written.
Table 4-9. Security States
SEC01:SEC00 Description
0:0 secure
0:1 secure
1:0 unsecured
1:1 secure
76543210
R0 0
KEYACC
00000
W
Reset 00000000
= Unimplemented or Reserved
Figure 4-8. FLASH Configuration Register (FCNFG)
Table 4-10. FCNFG Register Field Descriptions
Field Description
5
KEYACC
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 4.5, “Security.”
0 Writes to $FFB0–$FFB7 are interpreted as the start of a FLASH programming or erase command.
1 Writes to NVBACKKEY ($FFB0–$FFB7) are interpreted as comparison key writes.