MC9S12Q128_10 Datasheet, PDF (567/644 Pages) Freescale Semiconductor, Inc – HCS12 Microcontrollers

Chapter 20 128 Kbyte Flash Module (S12FTS128K1V1)
20.3 Memory Map and Registers
This section describes the FTS128K1 memory map and registers.
20.3.1 Module Memory Map
The FTS128K1 memory map is shown in Figure 20-2. The HCS12 architecture places the Flash array
addresses between 0x4000 and 0xFFFF, which corresponds to three 16 Kbyte pages. The content of the
HCS12 Core PPAGE register is used to map the logical middle page ranging from address 0x8000 to
0xBFFF to any physical 16K byte page in the Flash array memory.¹ The FPROT register (see Section
20.3.2.5) can be set to globally protect the entire Flash array. Three separate areas, one starting from the
Flash array starting address (called lower) towards higher addresses, one growing downward from the
Flash array end address (called higher), and the remaining addresses, can be activated for protection. The
Flash array addresses covered by these protectable regions are shown in Figure 20-2. The higher address
area is mainly targeted to hold the boot loader code since it covers the vector space. The lower address area
can be used for EEPROM emulation in an MCU without an EEPROM module since it can be left
unprotected while the remaining addresses are protected from program or erase. 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 described in Table 20-1.
Flash Address
0xFF00–0xFF07
0xFF08–0xFF0C
0xFF0D
0xFF0E
0xFF0F
Table 20-1. Flash Configuration Field
Size
(bytes)
8
5
1
1
1
Description
Backdoor Key to unlock security
Reserved
Flash Protection byte
Refer to Section 20.3.2.5, “Flash Protection Register (FPROT)”
Reserved
Flash Security/Options byte
Refer to Section 20.3.2.2, “Flash Security Register (FSEC)”
1. By placing 0x3E/0x3F in the HCS12 Core PPAGE register, the bottom/top fixed 16 Kbyte pages can be seen twice in the MCU
memory map.
Freescale Semiconductor
MC9S12Q128
567
Rev 1.10