Fujitsu FR81S User Manual
CHAPTER 45: FLASH MEMORY
4. Registers
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER : FLASH MEMORY
FUJITSU SEMICONDUCTOR CONFIDENTIAL
19
4.2. Flash Status Register : FSTR (Flash STatus Register)
The bit configuration of the flash status register is shown below.
This register indicates the flash state.
FSTR : Address 0843
H
(Access : Byte)
bit7
bit6
bit5
bit4
bit3
bit2
bit1
bit0
Reserved
FECCER
R
FHANG
FRDY
Initial value
-
-
-
-
-
0
0
1
Attribute RX,WX
RX,WX
RX,WX
RX,WX
RX,WX
R,W
R,WX
R,WX
[bit7 to bit3] Reserved
These bits are reserved. The read value is undefined. Writing has no effect on the operation.
[bit2] FECCERR ( Flash ECC Error coRRection ) : data read ECC correction occurred
This bit is set if an ECC error correction occurs while reading flash memory other than CPU instruction
read. This bit is cleared by writing "0".
FECCERR
Read
Write
0
An error correction by ECC has not occurred during
data read (initial value)
Clears this bit
1
ECC error correction occurred during data read
No effect
If there are errors in 2 bits or more in a single word, the read value of this bit is undefined.
When reading a CPU instruction, this bit is not set even if an ECC error correction occurs.
When both an ECC error and "0" writing occur simultaneously, the "0" writing will take priority.
[bit1] FHANG (Flash HANG) : Flash HANG state
This bit indicates the flash memory HANG state.
FHANG
Description
0
Normal state
1
HANGUP state
If there is a timing overrun (See "[bit5] TLOV: (Timing Limit Elapsed Flag Bit)), the flash memory will go
into the HANG state. If this bit becomes "1", issue a reset command (See "5.3.1. Command Sequence").
The correct value might not be read out immediately after a command of automatic algorithm has been
issued. In that case, ignore the first read value of this bit after the command issuance.
[bit0] FRDY (Flash ReaDY) : Flash write enable
This bit indicates whether the flash memory write/erase operation by automatic algorithm is currently
running or finished. Flash memory data cannot be written or erased while the operation is in progress.
MB91520 Series
MN705-00010-1v0-E
1940