CAT25C01 Datasheet, PDF (5/10 Pages) Catalyst Semiconductor – 1K/2K/4K/8K/16K SPI Serial CMOS E2PROM

Advanced Information
CAT25C01/02/04/08/16
HOLD: Hold
HOLD is the HOLD pin. The HOLD pin is used to pause
transmission to the CAT25C01/02/04/08/16 while in the
middle of a serial sequence without having to re-transmit
entire sequence at a later time. To pause, HOLD must be
brought low while SCK is low. The SO pin is in a high
impedance state during the time the part is paused, and
transitions on the SI pins will be ignored. To resume
communication, HOLD is brought high, while SCK is low.
(HOLD should be held high any time this function is not
being used.) HOLD may be tied high directly to VCC or
tied to VCC through a resistor. Figure 9 illustrates hold
timing sequence.
STATUS REGISTER
The Status Register indicates the status of the device.
The RDY (Ready) bit indicates whether the CAT25C01/
02/04/08/16 is busy with a write operation. When set to
1 a write cycle is in progress and when set to 0 the device
indicates it is ready. This bit is read onlyThe WEL (Write
Enable) bit indicates the status of the write enable latch.
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. The
WEL bit can only be set by the WREN instruction and can
be reset by the WRDI instruction.
STATUS REGISTER
7
6
5
4
WPEN PR_MODE SPI_MODE
X
3
2
1
0
BP1
BP0
WEL
RDY
BLOCK PROTECTION BITS
Status Register Bits
BP1
BP0
0
0
0
1
1
0
1
1
Array Address
Protected
None
25C01: 60-7F
25C02: C0-FF
25C04: 180-1FF
25C08: 0300-03FF
25C16: 0600-07FF
25C01: 40-7F
25C02: 80-FF
25C04: 100-1FF
25C08: 0200-03FF
25C16: 0400-07FF
25C01: 00-7F
25C02: 00-FF
25C04: 000-1FF
25C08: 0000-03FF
25C16: 0000-07FF
Protection
No Protection
Quarter Array Protection
Half Array Protection
Full Array Protection
WRITE PROTECT ENABLE OPERATION
WPEN
0
0
1
1
X
X
WP
X
X
Low
Low
High
High
WEL
0
1
0
1
0
1
Protected
Blocks
Protected
Protected
Protected
Protected
Protected
Protected
Unprotected
Blocks
Protected
Writable
Protected
Writable
Protected
Writable
Status
Register
Protected
Writable
Protected
Protected
Protected
Writable
5
Doc. No. 25067-00 5/00