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CHAPTER 22 DUAL OPERATION FLASH MEMORY
22.7 Details of Programming/Erasing Flash Memory
22.7.1
Read/Reset State in Flash Memory
This section explains the procedure for inputting the read/reset command to place flash
memory in the read/reset state.
■ Read/Reset State in Flash Memory
• Flash memory can be placed in the read/reset state by transmitting the read/reset command in the
command sequence table from CPU to flash memory.
• There are two kinds of read/reset commands: one is executed at one time bus operation, and the other is
executed at four times bus operation; the command sequence of both is essentially the same.
• Since the read/reset state is the initial state for flash memory, flash memory always enters this state after
power-on and at the normal termination of command. The read/reset state is also described as the wait
state for command input.
• In the read/reset state, a read access to flash memory enables data to be read. As is the case with mask
ROM, a program access from the CPU can be made.
• A read access to flash memory does not require the read/reset command. If the command is not
terminated normally, use the read/reset command to initialize the automatic algorithm.
502
FUJITSU MICROELECTRONICS LIMITED
MB90335 Series
CM44-10137-6E
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