SC312XDP512F0MPVR datasheet(1149/1348 Pages) FREESCALE

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Chapter 28 256 Kbyte Flash Module (S12XFTX256K2V1)

MC9S12XDP512 Data Sheet, Rev. 2.21

Freescale Semiconductor

1151

28.3

Memory Map and Register Deﬁnition

This section describes the memory map and registers for the Flash module.

28.3.1

Module Memory Map

The Flash memory map is shown in Figure 28-2. The HCS12X architecture places the Flash memory

addresses between global addresses 0x78_0000 and 0x7F_FFFF. The FPROT register, described in

Section 28.3.2.5, “Flash Protection Register (FPROT)”, 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 Flash memory map. The higher address region is mainly targeted to hold the boot

loader code since it covers the vector space. The lower address region 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 as described in

Table 28-1.

Table 28-1. Flash Conﬁguration Field

Global Address

Size

(Bytes)

Description

0x7F_FF00 – 0x7F_FF07

Backdoor Comparison Key

Refer to Section 28.6.1, “Unsecuring the MCU using Backdoor Key Access”

0x7F_FF08 – 0x7F_FF0C

Reserved

0x7F_FF0D

Flash Protection byte

Refer to Section 28.3.2.5, “Flash Protection Register (FPROT)”

0x7F_FF0E

Flash Nonvolatile byte

Refer to Section 28.3.2.8, “Flash Control Register (FCTL)”

0x7F_FF0F

Flash Security byte

Refer to Section 28.3.2.2, “Flash Security Register (FSEC)”

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