EN25P10
Read Status Register (RDSR) (05h)
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 7.
Table 6. Status Register Bit Locations
SRP
0
0
0
BP1
BP0
WEL
BUSY
Status Register Protect
Reserved Bits
Block Protect Bits
Write Enable Latch
Busy
The status and control bits of the Status Register are as follows:
BUSY bit.
The BUSY 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.
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 3.) 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.
Reserved bit.
Status register bit locations 5 and 6 are reserved for future use. Current devices will read 0
for these bit locations. It is recommended to mask out the reserved bit when testing the Status Register.
Doing this will ensure compatibility with future devices.
SRP bit.
The Status Register Protect (SRP) bit is operated in conjunction with the Write Protect (WP#)
signal. The Status Register Write Protect (SRP) bit and Write Protect (WP#) signal allow the device to be
put in the Hardware Protected mode (when the Status Register Protect (SRP) bit is set to 1, and Write
Protect (WP#) is driven Low). In this mode, the non-volatile bits of the Status Register (SRP, BP1, BP0)
become read-only bits and the Write Status Register (WRSR) instruction is no longer accepted for
execution.
This Data Sheet may be revised by subsequent versions
or modifications due to changes in technical specifications.
10
©2004 Eon Silicon Solution, Inc., www.essi.com.tw
Rev. C, Issue Date: 2007/5/4
EON [ EON SILICON SOLUTION INC. ]
