S9S08QD2CSC datasheet(47/198 Pages) FREESCALE

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Chapter 4 Memory Map and Register Definition

MC9S08QD4 Series MCU Data Sheet, Rev. 6

Freescale Semiconductor

4.7.3

Flash Configuration Register (FCNFG)

4.7.4

Flash Protection Register (FPROT and NVPROT)

During reset, the contents of the nonvolatile location NVPROT is copied from flash into FPROT. This

321

KEYACC

000

Reset

000

= Unimplemented or Reserved

Figure 4-7. Flash Configuration Register (FCNFG)

Table 4-10. FCNFG Register Field Descriptions

Field

Description

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 4.6, “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.

321

FPS(1)

FPDIS(1)

Reset

This register is loaded from nonvolatile location NVPROT during reset.

1 Background commands can be used to change the contents of these bits in FPROT.

Figure 4-8. Flash Protection Register (FPROT)

Table 4-11. FPROT Register Field Descriptions

Field

Description

7:1

FPS

Flash Protect Select Bits — When FPDIS = 0, this 7-bit field determines the ending address of unprotected

flash locations at the high address end of the flash. Protected flash locations cannot be erased or programmed.

FPDIS

Flash Protection Disable

0 Flash block specified by FPS7:FPS1 is block protected (program and erase not allowed).

1 No flash block is protected.

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