Freescale Semiconductor Block Guide, EETX4K 4.2 Wait Mode, 4.3 Stop Mode, 4.4 Background Debug Mode, 4.5 EEPROM Module Security

Block Guide — S12EETX4KV0 V00.04

4.2 Wait Mode

If a command is active (CCIF=0) when the MCU enters the WAIT mode, the active command and any

buffered command will be completed.

The EEPROM module can recover the MCU from WAIT if the CBEIF and CCIF interrupts are enabled

(see section 4.7).

4.3 Stop Mode

If a command is active (CCIF = 0) when the MCU enters the STOP mode, the operation will be aborted

and, if the operation is program, sector erase, mass erase, or sector modify, the EEPROM array data being

programmed or erased may be corrupted and the CCIF and ACCERR flags will be set. If active, the high

voltage circuitry to the EEPROM memory will immediately be switched off when entering STOP mode.

Upon exit from STOP, the CBEIF flag is set and any buffered command will not be launched. The

ACCERR flag must be cleared before starting a command write sequence (see section 4.1.2).

NOTE:

Asactive commands are immediately aborted when the MCU enters STOP mode, it

is strongly recommended that the user does not use the STOP command during

program, sector erase, mass erase, or sector modify operations.

4.4 Background Debug Mode

In background debug mode (BDM), the EPROT register is writable. If the MCU is unsecured, then all

EEPROM commands listed in Table 4-1 can be executed. If the MCU is secured and is in special single

chip mode, the only command available to execute is mass erase.

4.5 EEPROM Module Security

The EEPROM module does not provide any security information to the MCU. After each reset, the

securitystate of the MCU is a function of information provided by the Flash module (see the specific FTX

Block Guide).

Before the MCU can be unsecured in special single chip mode, the EEPROM memory must be erased

using the following method:

• Reset the MCU into special single chip mode, delay while the erase test is performed by the BDM

secure ROM, send BDM commands to disable protection in the EEPROM module, and execute a

mass erase command write sequence to erase the EEPROM memory.

After the CCIF flag sets to indicate that the EEPROM mass operation has completed and assuming that

the Flash memory has also been erased, reset the MCU into special single chip mode. The BDM secure

ROM will verify that the Flash and EEPROM memory are erased and will assert the UNSEC bit in the

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