A25L20P/A25L10P/A25L05P Series
Read Status Register (RDSR)
The Read Status Register (RDSR) instruction allows the
Status Register to be read. The Status Register may be read
at any time, even while a Program, Erase or Write Status
Register cycle is in progress. When one of these cycles is in
progress, it is recommended to check the Write In Progress
(WIP) bit before sending a new instruction to the device. It is
also possible to read the Status Register continuously, as
shown in Figure 6.
WEL bit. The Write Enable Latch (WEL) bit indicates the
status of the internal Write Enable Latch. When set to 1 the
internal Write Enable Latch is set, when set to 0 the internal
Write Enable Latch is reset and no Write Status Register,
Program or Erase instruction is accepted.
BP1, BP0 bits. The Block Protect (BP1, BP0) bits are
non-volatile. They define the size of the area to be software
protected against Program and Erase instructions. These bits
are written with the Write Status Register (WRSR) instruction.
When one or both of the Block Protect (BP1, BP0) bits is set
to 1, the relevant memory area (as defined in Table 1.)
becomes protected against Page Program (PP) and Sector
Erase (SE) instructions. The Block Protect (BP1, BP0) bits can
be written provided that the Hardware Protected mode has not
been set. The Bulk Erase (BE) instruction is executed if, and
only if, both Block Protect (BP1, BP0) bits are 0.
Table 6. Status Register Format
b7
b0
SRWD
0
0
BP1 BP0 WEL WIP
Status Register
Write Protect
SRWD bit. The Status Register Write Disable (SRWD) bit is
Block Protect Bits
operated in conjunction with the Write Protect ( ) signal.
W
The Status Register Write Disable (SRWD) bit and Write
Write Enable Latch Bit
Protect ( ) signal allow the device to be put in the Hardware
W
Protected mode (when the Status Register Write Disable
Write In Progress Bit
(SRWD) bit is set to 1, and Write Protect ( ) is driven Low).
W
In this mode, the non-volatile bits of the Status Register
(SRWD, BP1, BP0) become read-only bits and the Write
Status Register (WRSR) instruction is no longer accepted for
execution.
The status and control bits of the Status Register are as
follows:
WIP bit. The Write In Progress (WIP) bit indicates whether the
memory is busy with a Write Status Register, Program or
Erase cycle. When set to 1, such a cycle is in progress, when
reset to 0 no such cycle is in progress.
Figure 6. Read Status Register (RDSR) Instruction Sequence and Data-Out Sequence
S
0
1
2
3
4
5
6
7
8
9 10 11 12
14 15
13
C
Instruction
DIO
Status Register Out
Status Register Out
High Impedance
DO
5
7
6
4
3
2
1
0
7
6
5
4
3
2
1
0
7
MSB
MSB
(August, 2007, Version 1.0)
13
AMIC Technology Corp.
AMICC [ AMIC TECHNOLOGY ]
