Datasheet

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M95640, M95320
Read Status Register (RDSR)
The Read Status Register (RDSR) instruction al-
lows the Status Register to be read. The Status
Register may be read at any time, even while a
Write or Write Status Register cycle is in progress.
When one of these cycles is in progress, it is rec-
ommended 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 con-
tinuously, as shown in Figure 10..
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 or Write
Status Register cycle. When set to 1, such a cycle
is in progress, when reset to 0 no such cycle is in
progress.
WEL bit. The Write Enable Latch (WEL) bit indi-
cates 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 or Write Status Register in-
struction 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 Write instructions.
These bits are written with the Write Status Regis-
ter (WRSR) instruction. When one or both of the
Block Protect (BP1, BP0) bits is set to 1, the rele-
vant memory area (as defined in Table 4.) be-
comes protected against Write (WRITE)
instructions. The Block Protect (BP1, BP0) bits
can be written provided that the Hardware Protect-
ed mode has not been set.
SRWD bit. The Status Register Write Disable
(SRWD) bit is operated in conjunction with the
Write Protect (W
) signal. The Status Register
Write Disable (SRWD) bit and Write Protect (W
)
signal allow the device to be put in the Hardware
Protected mode (when the Status Register Write
Disable (SRWD) bit is set to 1, and Write Protect
(W
) is driven Low). In this mode, the non-volatile
bits of the Status Register (SRWD, BP1, BP0) be-
come read-only bits and the Write Status Register
(WRSR) instruction is no longer accepted for exe-
cution.
Figure 10. Read Status Register (RDSR) Sequence
C
D
S
21 3456789101112131415
Instruction
0
AI02031E
Q
7 6543210
Status Register Out
High Impedance
MSB
7 6543210
Status Register Out
MSB
7