S9S12XS256J0CAL Datasheet, PDF (654/738 Pages) Freescale Semiconductor, Inc – Microcontrollers

64 KByte Flash Module (S12XFTMR64K1V1)
the DFDIE and SFDIE interrupt enable bits to generate the Flash error interrupt request. For a detailed
description of the register bits involved, refer to Section 20.3.2.5, “Flash Configuration Register
(FCNFG)”, Section 20.3.2.6, “Flash Error Configuration Register (FERCNFG)”, Section 20.3.2.7, “Flash
Status Register (FSTAT)”, and Section 20.3.2.8, “Flash Error Status Register (FERSTAT)”.
The logic used for generating the Flash module interrupts is shown in Figure 20-27.
CCIE
CCIF
Flash Command Interrupt Request
DFDIE
DFDIF
SFDIE
SFDIF
Flash Error Interrupt Request
Figure 20-27. Flash Module Interrupts Implementation
20.4.4 Wait Mode
The Flash module is not affected if the MCU enters wait mode. The Flash module can recover the MCU
from wait via the CCIF interrupt (see Section 20.4.3, “Interrupts”).
20.4.5 Stop Mode
If a Flash command is active (CCIF = 0) when the MCU requests stop mode, the current Flash operation
will be completed before the CPU is allowed to enter stop mode.
20.5 Security
The Flash module provides security information to the MCU. The Flash security state is defined by the
SEC bits of the FSEC register (see Table 20-10). During reset, the Flash module initializes the FSEC
register using data read from the security byte of the Flash configuration field at global address
0x7F_FF0F.
The security state out of reset can be permanently changed by programming the security byte of the Flash
configuration field. This assumes that you are starting from a mode where the necessary P-Flash erase and
program commands are available and that the upper region of the P-Flash is unprotected. If the Flash
security byte is successfully programmed, its new value will take affect after the next MCU reset.
The following subsections describe these security-related subjects:
• Unsecuring the MCU using Backdoor Key Access
• Unsecuring the MCU in Special Single Chip Mode using BDM
• Mode and Security Effects on Flash Command Availability
S12XS Family Reference Manual, Rev. 1.13
654
Freescale Semiconductor