LE25S20XA Datasheet, PDF (7/24 Pages) ON Semiconductor – Serial Flash Memory

LE25S20XA
2. Status Registers
The status registers hold the operating and setting statuses inside the device, and this information can be read
(status register read) and the protect information can be rewritten (status register write). There are 8 bits in total,
and "Table 4 Status registers" gives the significance of each bit.
Table 4 Status Registers
Bit
Name
Bit0
RDY
Bit1
WEN
Bit2
BP0
Bit3
BP1
Bit4
BP2
Bit5
TB
Bit6
Bit7
SRWP
Logic
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Function
Ready
Erase/Program
Write disabled
Write enabled
Block protect information
Protecting area switch
Block protect
Upper side/Lower side switch
Reserved bits
Status register write enabled
Status register write disabled
Power-on Time Information
0
0
Nonvolatile information
Nonvolatile information
Nonvolatile information
Nonvolatile information
0
Nonvolatile information
2-1. Status register read
The contents of the status registers can be read using the status register read command. This command can be
executed even during the following operations.
 Small sector erase, sector erase, chip erase
 Page program
 Status register write
"Figure 5 Status Register Read" shows the timing waveforms of status register read. Consisting only of the first
bus cycle, the status register command outputs the contents of the status registers synchronized to the falling edge
of the clock (SCK) with which the eighth bit of (05h) has been input. In terms of the output sequence, SRWP (bit
7) is the first to be output, and each time one clock is input, all the other bits up to RDY (bit 0) are output in
sequence, synchronized to the falling clock edge. If the clock input is continued after RDY (bit 0) has been output,
the data is output by returning to the bit (SRWP) that was first output, after which the output is repeated for as long
as the clock input is continued. The data can be read by the status register read command at any time (even during
a program or erase cycle).
Figure 5 Status Register Read
CS
SCK
SI
SO
Mode 3
Mode 0
0 1 2 3 4 5 6 7 8 15 16 23
8CLK
05h
MSB
High Impedance
DATA DATA DATA
MSB MSB MSB
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