Datasheet

Chapter 4 Memory
MC9S08SG32 Data Sheet, Rev. 8
60 Freescale Semiconductor
4.7.6 FLASH Command Register (FCMD)
Only five command codes are recognized in normal user modes as shown in Table 4-13. Refer to Section
4.5.3, “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. Only blank check is
required 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 4.5.5, “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).
76543210
R00000000
W FCMD
Reset 00000000
Figure 4-10. FLASH Command Register (FCMD)
Table 4-13. 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 4-12. FSTAT Register Field Descriptions (continued)
Field Description