Freescale Semiconductor HCS08 Series, Reference Manual

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Chapter 4 Memory
MC9S08JS16 MCU Series Reference Manual, Rev. 4
Freescale Semiconductor 61
4.8.6 Flash Command Register (FCMD)
Only five command codes are recognized in normal user modes as shown in Table 4-15 . Refer to
Section 4.6.3, “Program and Erase Command Execution ” for a detailed discussion of flash programming
and erase operations.
All other command codes are illegal and generate an access error.
It is not necessary to perform a blank check command after a mass erase operation. Blank check is required
only as part of the security unlocking mechanism.
4
FACCERR
Access Error Flag — FACCERR is set automatically when the proper command sequence is not obeyed exactly
(the erroneous command is ignored), if a program or erase operation is attempted before the FCDIV register has
been initialized, or if the MCU enters stop while a command was in progress. For a more detailed discussion of
the exact actions that are considered access errors, see
Section 4.6.5, “Access Errors .” FACCERR is cleared by
writing a 1 to FACCERR. Writing a 0 to FACCERR has no meaning or effect.
0 No access error.
1 An access error has occurred.
2
FBLANK
Flash Verified as All Blank (erased) Flag — FBLANK is set automatically at the conclusion of a blank check
command if the entire flash array was verified to be erased. FBLANK is cleared by clearing FCBEF to write a new
valid command. Writing to FBLANK has no meaning or effect.
0 After a blank check command is completed and FCCF = 1, FBLANK = 0 indicates the flash array is not
completely erased.
1 After a blank check command is completed and FCCF = 1, FBLANK = 1 indicates the flash array is completely
erased (all 0xFF).
7 6 5 4 3 2 1 0
R 0 0 0 0 0 0 0 0
W FCMD7 FCMD6 FCMD5 FCMD4 FCMD3 FCMD2 FCMD1 FCMD0
Reset 0 0 0 0 0 0 0 0
Figure 4-12. Flash Command Register (FCMD)
Table 4-14. FCMD Register Field Descriptions
Field Description
FCMD[7:0] Flash Command Bits — See Table 4-15
Table 4-15. Flash Commands
Command FCMD Equate File Label
Blank check 0x05 mBlank
Byte program 0x20 mByteProg
Byte program — burst mode 0x25 mBurstProg
Page erase (512 bytes/page) 0x40 mPageErase
Mass erase (all flash) 0x41 mMassErase
Table 4-13. FSTAT Register Field Descriptions (continued)
Field Description