Chapter 4 Memory
MC9S08SG32 Data Sheet, Rev. 7
58
Freescale Semiconductor
4.7.6
FLASH Command Register (FCMD)
Only ve command codes are recognized in normal user modes as shown in
Table 4-13. Refer to
Sectionerase 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
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 Veried as All Blank (erased) Flag — FBLANK is set automatically at the conclusion of a blank check
command if the entire FLASH array was veried 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
R
00000000
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