Datasheet

Table 4-5. Reserved flash memory addresses

Address Register Name Bit 7 6 5 4 3 2 1 Bit 0

0xFF70

NV_BACKKEY0

BACKKEY0

0xFF71 NV_BACKKEY1 BACKKEY1

0xFF72 NV_BACKKEY2 BACKKEY2

0xFF73 NV_BACKKEY3 BACKKEY3

0xFF74 NV_BACKKEY4 BACKKEY4

0xFF75 NV_BACKKEY5 BACKKEY5

0xFF76 NV_BACKKEY6 BACKKEY6

0xFF77 NV_BACKKEY7 BACKKEY7

0xFF78 Reserved — — — — — — — —

0xFF79 Reserved — — — — — — — —

0xFF7A Reserved — — — — — — — —

0xFF7B Reserved — — — — — — — —

0xFF7C NV_FPROT

FPOPE

— FPHDIS FPH FPLDIS FPLS

0xFF7D NV_EEPROT

DPOPE

— DPS

0xFF7E NV_FOPT NV

0xFF7F

NV_FSEC

KEYEN 1 1 1 1 SEC

The 8-byte comparison key can be used to temporarily disengage memory security

provided the key enable field, NV_FSEC[KEYEN], is 10b. This key mechanism can be

accessed only through user code running in secure memory. A security key cannot be

entered directly through background debug commands. This security key can be disabled

completely by programming the NV_FSEC[KEYEN] bit to 0. If the security key is

disabled, the only way to disengage security is by mass erasing the flash if needed,

normally through the background debug interface and verifying that flash is blank. To

avoid returning to secure mode after the next reset, program the security bits,

NV_FSEC[SEC], to the unsecured state (10b).

4.4 Random-access memory (RAM)

This section describes the 4,096 bytes of RAM (random-access memory).

These devices include static RAM. The locations in RAM below 0x0100 can be accessed

using the more efficient direct addressing mode. Any single bit in this area can be

accessed with the bit manipulation instructions (BCLR, BSET, BRCLR, and BRSET).

Random-access memory (RAM)

MC9S08PA60 Reference Manual, Rev. 1, 9/2012

72 Freescale Semiconductor, Inc.