S9S12XS256J0CAL Datasheet, PDF (611/738 Pages) Freescale Semiconductor, Inc – Microcontrollers

64 KByte Flash Module (S12XFTMR64K1V1)
20.3 Memory Map and Registers
This section describes the memory map and registers for the Flash module. Read data from unimplemented
memory space in the Flash module is undefined. Write access to unimplemented or reserved memory space
in the Flash module will be ignored by the Flash module.
20.3.1 Module Memory Map
The S12X architecture places the P-Flash memory between global addresses 0x7F_0000 and 0x7F_FFFF
as shown in Table 20-2. The P-Flash memory map is shown in Figure 20-2.
Table 20-2. P-Flash Memory Addressing
Global Address
0x7F_0000 – 0x7F_FFFF
Size
(Bytes)
Description
64 K
P-Flash Block 0
Contains Flash Configuration Field
(see Table 20-3)
The FPROT register, described in Section 20.3.2.9, can be set to protect regions in the Flash memory from
accidental program or erase. Three separate memory regions, one growing upward from global address
0x7F_8000 in the Flash memory (called the lower region), one growing downward from global address
0x7F_FFFF in the Flash memory (called the higher region), and the remaining addresses in the Flash
memory, can be activated for protection. The Flash memory addresses covered by these protectable regions
are shown in the P-Flash memory map. The higher address region is mainly targeted to hold the boot loader
code since it covers the vector space. Default protection settings as well as security information that allows
the MCU to restrict access to the Flash module are stored in the Flash configuration field as described in
Table 20-3.
Table 20-3. Flash Configuration Field¹
Global Address
Size
(Bytes)
Description
0x7F_FF00 – 0x7F_FF07
Backdoor Comparison Key
8
Refer to Section 20.4.2.11, “Verify Backdoor Access Key Command,” and
Section 20.5.1, “Unsecuring the MCU using Backdoor Key Access”
0x7F_FF08 – 0x7F_FF0B²
4
Reserved
0x7F_FF0C²
1
P-Flash Protection byte.
Refer to Section 20.3.2.9, “P-Flash Protection Register (FPROT)”
0x7F_FF0D²
1
D-Flash Protection byte.
Refer to Section 20.3.2.10, “D-Flash Protection Register (DFPROT)”
0x7F_FF0E²
1
Flash Nonvolatile byte
Refer to Section 20.3.2.15, “Flash Option Register (FOPT)”
0x7F_FF0F²
1
Flash Security byte
Refer to Section 20.3.2.2, “Flash Security Register (FSEC)”
1 _{Older versions may have swapped protection byte addresses}
S12XS Family Reference Manual, Rev. 1.13
Freescale Semiconductor
611