Deleting Any Data Item From The Flash Memory (Sector Deletion) - Fujitsu F2MC-16LX Hardware Manual

CHAPTER 23 1M-BIT FLASH MEMORY
23.7.4 Deleting any Data Item from the Flash Memory (Sector
Deletion)
This section describes the procedure for deleting a data item from the flash memory
(sector deletion) by issuing the sector deletion command. Data can be deleted for
each sector and two or more sectors can be specified at the same time.
■ Flash Memory from which any Data Item is Deleted (Sector Deletion)
Any sector can be deleted from the flash memory by continuously sending sector deletion
commands, listed in the command sequence table (see Table 23.5-1 in Section "23.5 Activating
the Automatic Algorithm of the Flash Memory"), to the target sector within the flash memory.
❍ Specifying a sector
The sector deletion command is executed by six bus operations. The sector deletion wait of 50 µs
starts, in the 6th cycle, by writing the sector deletion code (30
accessed within the target sector. To delete two or more sectors, write the deletion code (30
the address within the target sector to be deleted in accordance with the above processing.
❍ Notes on specifying two or more sectors
The deletion starts when the sector deletion wait period of 50 µs from the writing of the last
sector deletion code is completed. In other words, to delete two or more sectors at the same
time, the address of the next deletion sector and the deletion code (6th cycle of the command
sequence) each must be input within 50 µs. If this limit is exceeded, the address and code may
not be accepted. The sector deletion timer (hardware sequence flag DQ3) can be used to
check whether the writing of the subsequent sector deletion code is valid. In this case, set the
address for reading the sector deletion timer so that it indicates the sector to be deleted.
■ Procedure for Deleting a Sector from the Flash Memory
The status of the automatic algorithm within the flash memory can be determined using the
hardware sequence flag (see Section "23.6 Confirming the Automatic Algorithm Execution
Status"). Figure 23.7-2 shows an example of the procedure for deleting a flash memory sector.
The toggle bit flag (DQ6) is used to confirm the end of deletion.
Note that the data to be read for flag checking is read from the sector to be deleted.
The toggle bit flag (DQ6) stops the toggle operation when the timing limit excess flag (DQ5)
changes to "1". Therefore, even if the timing limit excess flag (DQ5) is "1", the toggle bit flag
(DQ6) must be rechecked.
Similarly, because the data polling flag (DQ7) changes when the timing limit excess flag (DQ5)
changes, it must be rechecked.
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