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MCF51QE128 MCU Series Reference Manual, Rev. 3
76 Freescale Semiconductor
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Chapter 4 Memory
4.4.2.5 Flash Status Register (FSTAT)
The FSTAT register defines the operational status of the flash module. FCBEF, FPVIOL and FACCERR
are readable and writable. FBLANK is readable and not writable. The remaining bits read 0 and are not
writable.
76543210
R FCBEF FCCF FPVIOL FACCERR 0 FBLANK 0 0
Ww1c
w1c w1c
Reset11000000
Figure 4-7. Flash Status Register (FSTAT)
Table 4-14. FSTAT Field Descriptions
Field Description
7
FCBEF
Command Buffer Empty Flag. The FCBEF flag indicates that the command buffer is empty so that a new
command write sequence can be started when performing burst programming. Writing a 0 to the FCBEF flag has
no effect on FCBEF. Writing a 0 to FCBEF after writing an aligned address to the flash array memory, but before
FCBEF is cleared, aborts a command write sequence and causes the FACCERR flag to be set. Writing a 0 to
FCBEF outside of a command write sequence does not set the FACCERR flag. Writing a 1 to this bit clears it.
0 Command buffers are full.
1 Command buffers are ready to accept a new command.
6
FCCF
Command Complete Flag. The FCCF flag indicates that there are no more commands pending. The FCCF flag
is cleared when FCBEF is cleared and sets automatically upon completion of all active and pending commands.
The FCCF flag does not set when an active program command completes and a pending burst program
command is fetched from the command buffer. Writing to the FCCF flag has no effect on FCCF.
0 Command in progress.
1 All commands are completed.
5
FPVIOL
Protection Violation Flag. The FPVIOL flag indicates an attempt was made to program or erase an address in
a protected area of the flash memory during a command write sequence. Writing a 0 to the FPVIOL flag has no
effect on FPVIOL. Writing a 1 to this bit clears it. While FPVIOL is set, it is not possible to launch a command or
start a command write sequence.
0 No protection violation detected.
1 Protection violation has occurred.
4
FACCERR
Access Error Flag. The FACCERR flag indicates an illegal access has occurred to the flash memory caused by
either a violation of the command write sequence (see Section 4.5.1.2, “Command Write Sequence”), issuing an
illegal flash command (see Section 4.4.2.6, “Flash Command Register (FCMD)”), or the execution of a CPU
STOP instruction while a command is executing (FCCF = 0). Writing a 0 to the FACCERR flag has no effect on
FACCERR. Writing a 1 to this bit clears it. While FACCERR is set, it is not possible to launch a command or start
a command write sequence.
0 No access error detected.
1 Access error has occurred.
3 Reserved, should be cleared.