Chapter 4 Memory

4.4.2.5Flash 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.

 

 

7

 

6

5

4

 

3

 

2

1

 

0

R

 

FCBEF

FCCF

FPVIOL

FACCERR

 

0

 

FBLANK

0

 

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

W

 

 

w1c

 

w1c

w1c

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Reset

1

1

0

0

 

0

 

0

0

 

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 4-7. Flash Status Register (FSTAT)

 

 

 

 

 

 

 

 

 

Table 4-14. FSTAT Field Descriptions

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Field

 

 

 

 

 

Description

 

 

 

 

 

 

 

 

7

 

 

Command Buffer Empty Flag. The FCBEF flag indicates that the command buffer is empty so that a new

FCBEF

 

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

 

 

Command Complete Flag. The FCCF flag indicates that there are no more commands pending. The FCCF flag

FCCF

 

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

 

 

Protection Violation Flag. The FPVIOL flag indicates an attempt was made to program or erase an address in

FPVIOL

 

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

 

 

Access Error Flag. The FACCERR flag indicates an illegal access has occurred to the flash memory caused by

FACCERR

 

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.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

MCF51QE128 MCU Series Reference Manual, Rev. 3

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Freescale Semiconductor MCF51QE128RM manual Flash Status Register Fstat, Fcbef Fccf Fpviol Faccerr Fblank, W1c