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MB95630H Series
25.4
Checking Automatic Algorithm Execution Status
Since the Flash memory uses the automatic algorithm to execute the program/
erase flow, its internal operating status can be checked through the hardware
sequence flags.
■ Hardware Sequence Flags
● Overview of hardware sequence flags
The hardware sequence flag consists of the following 5-bit output:
•
Data polling flag (DQ7)
•
Toggle bit flag (DQ6)
•
Execution timeout flag (DQ5)
•
Sector erase timer flag (DQ3)
•
Toggle bit2 flag (DQ2)
The hardware sequence flags can tell whether a program command, a chip erase command or a
sector erase command has been terminated, whether an erase code can be written and whether
an erase sector or a non-erase sector is being read.
The value of a hardware sequence flag can be checked by a read access to the address of a
target sector in the Flash memory after a command sequence is set. Note that a hardware
sequence flag is output only to the bank from which a command has been issued.
Table 25.4-1 shows the bit allocation of the hardware sequence flags.
Table 25.4-1
Bit Allocation of Hardware Sequence Flag
Bit no.
Hardware sequence flag
•
To decide whether a program command, a chip erase command or a sector erase command
is being executed or has been terminated, check the respective hardware sequence flags or
the flash memory program/erase status bit in the flash memory status register (FSR:RDY).
After programming/erasing is terminated, the Flash memory returns to the read/reset state.
•
When creating a program/erase program, read data after confirming the termination of
programming/erasing using the DQ2, DQ3, DQ5, DQ6 and DQ7 flags.
•
The hardware sequence flags can also be used to check whether the second sector erase
code write and those to be executed afterward are valid or not.
MN702-00009-1v0-E
CHAPTER 25 DUAL OPERATION FLASH MEMORY
7
6
DQ5
DQ7
DQ6
FUJITSU SEMICONDUCTOR LIMITED
25.4 Checking Automatic Algorithm
5
4
3
-
DQ3
DQ2
Execution Status
2
1
0
-
-
537
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