mc9s08jm60 Freescale Semiconductor, Inc, mc9s08jm60 Datasheet - Page 50

• Manufacturer Part Number: mc9s08jm60
• Description: Hcs08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

1
0xFFAE
0xFFAF
0xFFB0–
0xFFB7
0xFFB8–
0xFFBC
0xFFBD
0xFFBE
0xFFBF
0x1857
0x1858
0x1859
0x185A
0x185B–
0x185F
Address
Chapter 4 Memory
Nonvolatile flash registers, shown in
an 8-byte backdoor key which optionally can be used to gain access to secure memory resources. During
reset events, the contents of NVPROT and NVOPT in the nonvolatile register area of the flash memory
are transferred into corresponding FPROT and FOPT working registers in the high-page registers to
control security and block protection options.
Provided the key enable (KEYEN) bit is 1, the 8-byte comparison key can be used to temporarily
disengage memory security. 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 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 (SEC01:SEC00) to the unsecured state (1:0).
4.3
The MC9S08JM60 series includes static RAM. The locations in RAM below 0x0100 can be accessed
using the more efficient direct addressing mode, and any single bit in this area can be accessed with the bit
manipulation instructions (BCLR, BSET, BRCLR, and BRSET). Locating the most frequently accessed
program variables in this area of RAM is preferred.
50
Address
This reserved bit must always be written to 0.
Reserved for
storage of FTRIM
Res. for storage of
MCGTRIM
NVBACKKEY
Reserved
NVPROT
Reserved
NVOPT
Reserved
PTGPE
PTGSE
PTGDS
Reserved
RAM (System RAM)
Register Name
Register Name
Table 4-3. High-Page Register Summary (Sheet 3 of 3)
KEYEN
FPS7
Bit 7
Bit 7
—
—
—
—
—
—
—
0
Table 4-4. Nonvolatile Register Summary
MC9S08JM60 Series Data Sheet, Rev. 2
FNORED
Table
FPS6
—
—
—
—
—
—
—
6
6
0
4-4, are located in the flash memory. These registers include
PTGPE5
PTGSE5
PTGDS5
FPS5
—
—
—
—
5
5
0
0
8-Byte Comparison Key
PTGDS4
PTGPE4
PTGSE4
FPS4
—
—
—
—
4
4
0
0
TRIM
PTGPE3
PTGSE3
PTGDS3
FPS3
—
—
—
—
3
3
0
0
PTGDS2
PTGPE2
PTGSE2
FPS2
—
—
—
—
2
2
0
0
Freescale Semiconductor
PTGPE1
PTGSE1
PTGDS1
SEC01
FPS1
—
—
—
—
1
1
0
PTGDS0
PTGPE0
PTGSE0
SEC00
FTRIM
FPDIS
Bit 0
Bit 0
—
—
—
—