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CHAPTER 19 512K-BIT (64 KB) FLASH MEMORY
Note:
The operation termination flag bit (RDYINT) and the write/erase status bit (RDY) are not
changed simultaneously.
Write programs in such a way that whether the write/erase
operation has terminated is determined by either of the two bits.
Table 19.3-1 Functional Explanation of Each Bits of the Flash Memory Control Status Register (FMCS)
Bit name
Function
bit7
INTE:
Interrupt request
enable bit
This bit enables output of an interrupt request to the CPU when write/
erase operation of flash memory terminates.
When the RDYINT bit is set to "1" while this bit is set to "1", an interrupt
request is output.
Even if the RDYINT bit is set to "1", no interrupt request is output while
this bit is "0".
bit6
RDYINT:
write/erase operation
termination flag bit
When write/erase operation of flash memory terminates, this bit is set to
"1", enabling write/erase operation to the flash memory.
When this bit is set to "0", it is cleared to "0", disabling write/erase
operation to the flash memory.
When this bit is set to "1", operation is not affected.
This bit is also set to "1" when the automatic algorithm in flash memory
terminates. (For details, see Section 19.4, "Method of Starting the
Automatic Algorithm in Flash Memory.")
When a read-modify-write (RMW) instruction is used, "1" is always read.
bit5
WE:
write/erase operation
enable flag bit
When this bit is "1", write/erase operation to the flash memory can be
performed after executing a write/erase command sequence to bank FF.
(For details, see Section 19.4, "Method of Starting the Automatic
Algorithm in Flash Memory.")
When this bit is "0", no write/erase signal is generated even after
executing a write/erase command sequence to bank FF.
This bit is set to "0" as its initial value, disabling operation. Before
activating a write/erase command to the flash memory, be sure to set
this bit to "1" to enable operation.
Note:
Set this bit to "0" if you do not want to perform write/erase operation.
bit4
RDY:
Write/erase status bit
While this bit is cleared to "0", it is not possible to perform write/erase
operation to the flash memory.
Even if this bit is cleared to "0", the read/reset commands and suspend
commands such as the selector erase/halt commands can be accepted.
This bit is set to "1" when write/erase operation terminates.
bit3
bit1
Reserved:
Reserved bit
Always set this bit to "1".
bit2
bit0
LPM1,LPM0:
Low-power
consumption mode
setting bit
This bit is used to set the access time from the CPU to the flash
memory.
The values that can be set vary depending on the internal operating
frequency.
With decreasing internal operating frequency, power consumption by the
flash memory unit can be reduced.