Erasing Arbitrary Data In Flash Memory (Sector Erase) - Fujitsu F2MC-16LX Hardware Manual

CHAPTER 26 2M BIT FLASH MEMORY

26.6.4 Erasing Arbitrary Data in Flash Memory (Sector Erase)

This section describes the procedure for issuing a sector erase command to erase an
arbitrary sector in flash memory. This procedure allows either erasure of individual
sectors or erasure of multiple sectors at the same time to be specified.
I Erasing arbitrary data in the flash memory (sector erase)
To erase an arbitrary sector in flash memory, repeatedly send the sector erase command in the
command sequence table (see Table 26.4-1 "Command sequence table") to the relevant sector
in the flash memory.
❍ Method for specifying a sector
The sector erase command is performed in six bus operations. To start a sector erase wait of
50µs, write the sector erase code (30
target sector that can be accessed. To erase multiple sectors using the above procedure, write
the erase code (30
❍ Notes on specifying multiple sectors
Erase operation starts when the sector erase wait time of 50 µs has elapsed after the last sector
erase code has been written. In other words, to erase multiple sectors at the same time, enter
the next erase sector address and erase code (which must be entered in the 6th cycle of the
command sequence) within 50 µs. After this time limit is exceeded, the sector address or erase
code may not be accepted. Whether the next sector erase code can be written can be checked
using the sector erase timer (hardware sequence flag:DQ3). In this case, the address for
reading the sector erase timer must also specify the sector to be erased.
I Procedure for sector erasure
The hardware sequence flag (see Section 26.5 "Verifying the Execution State of the Automatic
Algorithm") can be used to identify the operational state of the automatic algorithm operating on
the internal flash memory. Figure 26.6-2 "Example of sector erase procedure for flash memory"
shows an example of the procedure for sector erasure of the flash memory. In this example, the
toggle bit flag (DQ6) is used to check for the end of erasure.
Be sure that the data read in the flag check is data from the sector to be read.
The toggle bit flag (DQ6) stops the toggle operation when the timing limit excess flag (DQ5)
changes to "1". Therefore, even if DQ5 is "1", check the toggle bit flag (DQ6) again.
The data polling flag (DQ7) also changes when the timing limit excess flag (DQ5) changes.
Therefore, check the data polling flag (DQ7) again.
488
) in the 6th cycle to an arbitrary even address in the
H
) sequentially to the addresses of the target sector to be erased.
H