CAT25080, CAT25160
STATUS REGISTER
The Status Register, as shown in Table 2, contains a
number of status and control bits.
user with the WRSR command and are non-volatile.
The user is allowed to protect a quarter, one half or the
entire memory, by setting these bits according to Table
3. The protected blocks then become read-only.
¯¯¯¯
The RDY (Ready) bit indicates whether the device is
busy with a write operation. This bit is automatically set
to 1 during an internal write cycle, and reset to 0 when
the device is ready to accept commands. For the host,
this bit is read only.
The WPEN (Write Protect Enable) bit acts as an enable
¯¯¯
for the WP pin. Hardware write protection is enabled
¯¯¯
when the WP pin is low and the WPEN bit is 1. This
condition prevents writing to the status register and to
the block protected sections of memory. While
hardware write protection is active, only the non-block
protected memory can be written. Hardware write
The WEL (Write Enable Latch) bit is set/reset by the
WREN/WRDI commands. When set to 1, the device is
in a Write Enable state and when set to 0, the device is
in a Write Disable state.
¯¯¯
protection is disabled when the WP pin is high or the
¯¯¯
WPEN bit is 0. The WPEN bit, WP pin and WEL bit
The BP0 and BP1 (Block Protect) bits determine which
blocks are currently write protected. They are set by the
combine to either permit or inhibit Write operations, as
detailed in Table 4.
Table 2. Status Register
7
6
0
5
0
4
0
3
2
1
0
¯¯¯¯
RDY
WPEN
BP1
BP0
WEL
Table 3. Block Protection Bits
Status Register Bits
Array Address Protected
Protection
BP1
BP0
0
0
None
No Protection
25080: 0300-03FF
25160: 0600-07FF
25080: 0200-03FF
25160: 0400-07FF
25080: 0000-03FF
25160: 0000-07FF
0
1
1
1
0
1
Quarter Array Protection
Half Array Protection
Full Array Protection
Table 4. Write Protect Conditions
Protected
Blocks
Unprotected
Status
Register
¯¯¯
WP
WPEN
WEL
Blocks
Protected
Writable
Protected
Writable
Protected
Writable
0
0
1
1
X
X
X
0
1
0
1
0
1
Protected
Protected
Protected
Protected
Protected
Protected
Protected
Writable
X
Low
Low
High
High
Protected
Protected
Protected
Writable
© 2006 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
5
Doc. No. 1122 Rev. A
CATALYST [ CATALYST SEMICONDUCTOR ]
