ROHS MC9S08QE128 Reference Manual page 78

Chapter 4 Memory
If the FCDIV register is written, the FDIVLD bit is set automatically. If the FDIVLD bit is 0, the FCDIV
register has not been written since the last reset. If the FCDIV register has not been written to, the flash
command loaded during a command write sequence will not execute and the FACCERR flag in the FSTAT
register will set.
4.6.3.1.2 Command Write Sequence
The flash command controller is used to supervise the command write sequence to execute program, erase,
and erase verify algorithms.
Before starting a command write sequence, the FACCERR and FPVIOL flags in the FSTAT register must
be clear and the FCBEF flag must be set (see
A command write sequence consists of three steps which must be strictly adhered to with writes to the flash
module not permitted between the steps. However, flash register and array reads are allowed during a
command write sequence. The basic command write sequence is as follows:
1. Write to a valid address in the flash array memory.
2. Write a valid command to the FCMD register.
3. Clear the FCBEF flag in the FSTAT register by writing a 1 to FCBEF to launch the command.
Once a command is launched, the completion of the command operation is indicated by the setting of the
FCCF flag in the FSTAT register. The FCCF flag will set upon completion of all active and buffered burst
program commands.
4.6.3.2 Flash Commands
Table 4-23 summarizes the valid flash commands along with the effects of the commands on the flash
block.
NVM
FCMDB
Command
0x05 Erase
Verify
0x20 Program
0x25 Burst
Program
0x40 Sector
Erase
0x41 Mass
Erase
A flash block address must be in the erased state before being programmed.
Cumulative programming of bits within a flash block address is not allowed
except for status field updates required in EEPROM emulation applications.
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Section
Table 4-23. Flash Command Description
Verify all memory bytes in the flash array memory are erased.
If the flash array memory is erased, the FBLANK flag in the FSTAT register will set upon
command completion.
Program an address in the flash array.
Program an address in the flash array with the internal address incrementing after the
program operation.
Erase all memory bytes in a sector of the flash array.
Erase all memory bytes in the flash array.
A mass erase of the full flash array is only possible when no protection is enabled prior
to launching the command.
CAUTION
MC9S08QE128 MCU Series Reference Manual, Rev. 2
4.6.2.5).
Function on Flash Memory
Freescale Semiconductor