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ColdFire Flash Module (CFM)
MCF52211 ColdFire® Integrated Microcontroller Reference Manual, Rev. 2
Freescale Semiconductor 18-29
18.4.2.3.5 Flash Normal Mode Illegal Operations
The ACCERR flag is set during the command write sequence if any of the following illegal operations are
performed, causing the command write sequence to immediately abort:
• Writing to the flash memory before initializing CFMCLKD.
• Writing to the flash memory while CBEIF is not set.
• Writing to a flash block with a data size other than 32 bits.
• After writing to the flash even block, writing an additional word to the flash memory during the
flash command write sequence other than the flash odd block.
• Writing an invalid flash normal mode command to the CFMCMD register.
• Writing to any CFM register other than CFMCMD after writing to the flash memory.
• Writing a second command to the CFMCMD register before executing the previously written
command.
• Writing to any CFM register other than CFMUSTAT (to clear CBEIF) after writing to the
command register, CFMCMD.
• The part enters stop mode and any command is in progress. Upon entering STOP mode, any active
command is aborted.
• Aborting a command write sequence by writing a 0 to the CBEIF flag after writing to the flash
memory or after writing a command to the CFMCMD register but before the command is launched.
The PVIOL flag is set during the command write sequence if any of the following illegal operations are
performed, causing the command write sequence to immediately abort:
• Writing a program command if the address to program is in a protected flash logical sector.
• Writing a page erase command if the address to erase is in a protected flash logical sector.
• Writing a mass erase command while any protection is enabled.
If a read operation is attempted on a flash logical block while a command is active on that logical block
(CCIF=0), the read operation returns invalid data and the ACCERR flag in the CFMUSTAT register is not
set.
18.4.2.4 Stop Mode
If a command is active (CCIF=0) when the MCU enters stop mode, the flash command controller and flash
memory controller performs the following:
• The active command is aborted. Therefore, if data was being programmed, it is now lost.
• The high voltage circuitry to the flash arrays is switched off.
• Any buffered command (CBEIF=0)is not executed after the MCU exits stop mode.
• The CCIF and ACCERR flags is set if a command is active when the MCU enters stop mode.
CAUTION
As active commands are immediately aborted when the MCU enters stop
mode, it is strongly recommended not to execute the stop instruction during
program and erase operations.