MC9S08GB32 Motorola, MC9S08GB32 Datasheet - Page 56

• Manufacturer Part Number: MC9S08GB32
• Description: Microcontrollers
• Manufacturer: Motorola

Chapter 4 Memory
SEC01:SEC00 — Security State Code
SEC01:SEC00 changes to 1:0 after successful backdoor key entry or a successful blank check of FLASH.
4.6.3
Bits 7 through 5 may be read or written at any time. Bits 4 through 0 always read 0 and cannot be written.
KEYACC — Enable Writing of Access Key
4.6.4
During reset, the contents of the nonvolatile location NVPROT is copied from FLASH into FPROT. Bits 0,
1, and 2 are not used and each always reads as 0. This register may be read at any time, but user program
writes have no meaning or effect. Background debug commands can write to FPROT.
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This 2-bit field determines the security state of the MCU as shown in
secure, the contents of RAM and FLASH memory cannot be accessed by instructions from any
unsecured source including the background debug interface. For more detailed information about
security, refer to
This bit enables writing of the backdoor comparison key. For more detailed information about the
backdoor key mechanism, refer to
1 = Writes to NVBACKKEY ($FFB0–$FFB7) are interpreted as comparison key writes.
0 = Writes to $FFB0–$FFB7 are interpreted as the start of a FLASH programming or erase
FLASH Configuration Register (FCNFG)
Reads of the FLASH return invalid data.
command.
FLASH Protection Register (FPROT and NVPROT)
Section 4.5,
Reset:
Read:
Write:
Figure 4-6. FLASH Configuration Register (FCNFG)
Bit 7
0
0
“Security.”
SEC01:SEC00
= Unimplemented or Reserved
MC9S08GB/GT Data Sheet, Rev. 2.3
Section 4.5,
Table 4-7. Security States
0:0
0:1
1:0
1:1
6
0
0
KEYACC
5
0
“Security.”
Description
unsecured
4
0
0
secure
secure
secure
3
0
0
Table
2
0
0
4-7. When the MCU is
Freescale Semiconductor
1
0
0
Bit 0
0
0