CAT25C021P-17TE13 View Datasheet(PDF) - Catalyst Semiconductor => Onsemi

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CAT25C021P-17TE13

Supervisory circuits with SPI serial E2EPROM, precision reset controller and watchdog timer

Catalyst Semiconductor => Onsemi 

CAT25CXXX

Advanced

Status Register

The Status Register indicates the status of the device.

The RDY (Ready) bit indicates whether the CAT25CXXX

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 only.The 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.

The BPO and BP1 (Block Protect) bits indicate which

blocks are currently protected. These bits are set by the

user issuing the WRSR instruction. The user is allowedto

protect quarter of the memory, half of the memory or the

entire memory by setting these bits. Once protectedthe

user may only read from the protected portion of the

array. These bits are non-volatile.

The WPEN (Write Protect Enable) is an enable bit for the

WP pin. The WP pin and WPEN bit in the status register

control the programmable hardware write protect fea-

ture. Hardware write protection is enabled when WP is

low and WPEN bit is set to high. The user cannot write

to the status register, (including the block protect bits

and the WPEN bit) and the block protected sections in

the memory array when the chip is hardware write

protected. Only the sections of the memory array that

are not block protected can be written. Hardware write

protection is disabled when either WP pin is high or the

WPEN bit is zero.

The watchdog timer bits, WD0 and WD1, select the

watchdog time-out period. These nonvolatile bits are

programmed with the WRSR instruction.

BLOCK PROTECTION BITS

Status Register Bits

BP1

BPO

0

0

0

1

1

0

1

1

Array Address

Protected

None

25C02X: C0-FF

25C04X: 180-1FF

25C08X: 0300-03FF

25C16X: 0600-07FF

25C32X: 0C00-0FFF

25C02X: 80-FF

25C04X: 100-1FF

25C08X: 0200-03FF

25C16X: 0400-07FF

25C32X: 0800-0FFF

25C02X: 00-FF

25C04X: 000-1FF

25C08X: 0000-03FF

25C16X: 0000-07FF

25C32X: 0000-0FFF

WATCHDOG TIMER BITS

WD1

0

0

1

1

WD0

0

1

0

1

Watchdog Timer Time-Out (Typical)

1.4 Seconds

600 Milliseconds

200 Milliseconds

Disabled

Protection

No Protection

Quarter Array Protection

Half Array Protection

Full Array Protection

Stock No. 21085-01 4/98

9-100

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