HCS08 datasheet(39/198 Pages) NXP

39 / 198 page

Chapter 4 Memory Map and Register Definition

MC9S08QD4 Series MCU Data Sheet, Rev. 6

Freescale Semiconductor

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 following any reset before using any flash

commands.

Figure 4-2. Flash Program and Erase Flowchart

4.5.4

Burst Program Execution

The burst program command is used to program sequential bytes of data in less time than would be

required using the standard program command. This is possible because the high voltage to the flash array

does not need to be disabled between program operations. Ordinarily, when a program or erase command

is issued, an internal charge pump associated with the flash memory must be enabled to supply high

voltage to the array. Upon completion of the command, the charge pump is turned off. When a burst

START

WRITE TO FLASH

TO BUFFER ADDRESS AND DATA

WRITE COMMAND TO FCMD

YES

FPVIO OR

WRITE 1 TO FCBEF

TO LAUNCH COMMAND

AND CLEAR FCBEF (2)

FCCF ?

ERROR EXIT

DONE

(2) Wait at least four bus cycles before

checking FCBEF or FCCF.

FACCERR ?

CLEAR ERROR

FACCERR ?

WRITE TO FCDIV(1)

(1) Required only once

after reset.

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