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MB90420/5 (A) SERIES F
MC-16LX FAMILY 16-BIT MICROCONTROLLERS HARDWARE MANUAL
25.7 Details of Programming to and Erasing from Flash Memory
This section explains the procedure for issuing commands starting the aoutomatic algorithm, and for read
from/reset of flash memory, programming, chip erasing, sector erasing, sector erasing suspention and sector
erasing resumption.
n Detailed explanation of programming to and erasing from for flash memory
Flash memory can execute the automatic algorithm by repeating the bus write cycle of command sequences
in the read/reset, program, chip erase, sector erase, sector erasing suspend and erasing resume (see Table
25-2 of 25.5). The bus write cycle must be repeated continuously. The data polling function can be used to
check the completion of the automatic algorithm. After normal completion, the flash memory returns to the
read/reset state.
Each operation is given on the following pages.
• Read/reset state in flash memory
• Data Programming
• All data erasing (Chip erase)
• Any data erasing (Sector erase)
• Sector erasing suspention
• Sector erasing resumption
25.7.1 Read/reset State in Flash Memory
This section explains the procedure for issuing the read/reset command to place flash memory in the
read/reset state.
n Read/reset state in flash memory
Flash memory can be placed in the read/reset state by sending the read/reset command in the command
sequence table (see Table 25-2 of Section 25.5) to a target sector in flash memory.
There are two read/reset commands: one is executed at once bus operation, and the other is executed at
three times bus operations; the command sequence of both is essentially the same.
Flash memory is in the read/reset state at default and always enters this state at power-on and at the normal
termination of command execution. The read/reset state can be the wait state for input of other command.
In the read/reset state, data can be read by normal read access. When the CPU is in the normal mode, like
mask ROM, program access from the CPU is enabled.
Consequently, this command is not needed for reading data in the normal state and is used mainly to reset
the automatic algorithm when command execution has not terminated for some reason.
25-16
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