Fujitsu MB90460 Series Hardware Manual page 610

[bit4] RDY (Ready)
This bit is the flash memory write/delete permission bit.
While this bit is "0", the write/delete cannot be executed to the flash memory. Even in this state,
however, suspend commands such as the read/reset command and the sector deletion temporary stop
can be accepted.
0: During the write/delete operation
1: Write/delete operation terminated (Next data write/delete operation permitted)
[bit3, bit1] Reserved bits
These bits are the reserved bits for testing. When these bits are usually used, they must be set to "0".
[bit2, bit0] LPM1, LPM0 (Low-power Mode)
These bits control the current consumption in the flash memory when accessing the flash memory.
However, the access time from the CPU to the flash memory greatly dependent upon the setting.
Therefore, the set values should be selected, depending on the CPU operating frequency.
01: Low-power consumption mode
10: Low-power consumption mode
11: Low-power consumption mode
00: Normal power consumption mode
Note:
The RDYINT bit and RDY bit are not changed simultaneously. Create a program using one of the
RDYINT bit or RDY bit for determination.
Automatic algorithm
Termination time
RDYINT bit
RDY bit
(Internal operating frequency operating at 4 MHz or less)
(Internal operating frequency operating at 8 MHz or less)
(Internal operating frequency operating at 10 MHz or less)
(Internal operating frequency operating at 12.58 MHz or less)
CHAPTER 23 512K / 1024K BIT FLASH MEMORY
1 machine cycle
591