MC9S08JM60_09 Datasheet, PDF (53/388 Pages) Freescale Semiconductor, Inc – HCS08 Microcontrollers

Chapter 4 Memory
2. Write the command code for the desired command to FCMD. The five valid commands are blank
check (0x05), byte program (0x20), burst program (0x25), page erase (0x40), and mass erase
(0x41). The command code is latched into the command buffer.
3. Write a 1 to the FCBEF bit in FSTAT to clear FCBEF and launch the command (including its
address and data information).
A partial command sequence can be aborted manually by writing a 0 to FCBEF any time after the write to
the memory array and before writing the 1 that clears FCBEF and launches the complete command.
Aborting a command in this way sets the FACCERR access error flag which must be cleared before
starting a new command.
A strictly monitored procedure must be obeyed or the command will not be accepted. This minimizes the
possibility of any unintended changes to the flash memory contents. The command complete flag (FCCF)
indicates when a command is complete. The command sequence must be completed by clearing FCBEF
to launch the command. Figure 4-2 is a flowchart for executing all of the commands except for burst
programming. The FCDIV register must be initialized before using any flash commands. This only must
be done once following a reset.
WRITE TO FCDIV ^{(Note 1)}
Note 1: Required only once after reset.
FLASH PROGRAM AND
ERASE FLOW
START
0
FACCERR ?
1
CLEAR ERROR
WRITE TO FLASH
TO BUFFER ADDRESS AND DATA
WRITE COMMAND TO FCMD
WRITE 1 TO FCBEF
TO LAUNCH COMMAND
AND CLEAR FCBEF ^{(Note 2)}
Note 2: Wait at least four bus cycles
before checking FCBEF or FCCF.
FPVIOL OR
YES
FACCERR ?
NO
ERROR EXIT
0
FCCF ?
1
DONE
Figure 4-2. Flash Program and Erase Flowchart
MC9S08JM60 Series Data Sheet, Rev. 3
Freescale Semiconductor
53