TU25C256(1998) データシートの表示（PDF） - Turbo IC Inc

部品番号

コンポーネント説明

メーカー

TU25C256
(Rev.:1998)

CMOS SPI BUS 256K ELECTRICALLY ERASABLE PROGRAMMABLE ROM 32K X 8 BIT EEPROM

Turbo IC Inc 

Turbo IC, Inc.

25C256

PRELIMINARY INFORMATION

Where, WPEN is the write protect enable bit. Setting WPEN to a

"1" enables the hardware write protect, and a "0"

disables the hardware write protect. This bit is

non-volatile and is programmed by the WRSR instruction.

This bit works in conjunction with the the Write

Protect (WP) pin to control the hardware write protect

feature. Hardware write protection is enabled when

the WP pin is low and the WPEN bit is "1". Hardware

write protection is disabled when either the WP pin

is high or the WPEN bit is "0". When the hardware

write protection is on, only the writes to the

the non-volatile bits (WPEN, BP1, BP0) are disabled.

It is noted that the write enable latch must also

be set before the non-volatile bits can be programmed.

Bits[6:4] are "0" except when the status register is being

programmed. These bits are read-only.

BP[1:0] are the block write protect bits. These bits

specifies which blocks in the memory array are

write protected, as indicated in Table 3. These bits

are non-volatile and are programmed by the WRSR

instruction.

WEN indicates the status of the write enable latch. A "1"

means that the write enable latch is set. A "0" means

that the write enable latch is cleared. This bit

is read-only.

BSY indicates the status of the internal write cyle to the

memory array. A "1" means that the write cycle is in

progress. A "0" means the write cycle has finished

and the device is ready for the next instruction.

This bit is read-only.

Table 3 Block "Write Protect" Assignment

---------------------------------------------------------------------------------------------

Status Register Fraction of Array Write Protected Memory Blocks

BP1 BP0 Write Protected

25C256

---------------------------------------------------------------------------------------------

0

0

0

None

---------------------------------------------------------------------------------------------

0

1

1/4

6000-

7FFF

---------------------------------------------------------------------------------------------

1

0

1/2

4000-

7FFF

---------------------------------------------------------------------------------------------

1

1

All

0000-

7FFF

---------------------------------------------------------------------------------------------

3

Share Link: