M25P05-A

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Protection Modes

The environments where non-volatile memory de-

vices are used can be very noisy. No SPI device

can operate correctly in the presence of excessive

noise. To help combat this, the M25P05-A boasts

the following data protection mechanisms:

s

can provide protection against inadvertant

changes while the power supply is outside the

operating specification.

s

Program, Erase and Write Status Register

instructions are checked that they consist of a

number of clock pulses that is a multiple of

eight, before they are accepted for execution.

s

All instructions that modify data must be

preceded by a Write Enable (WREN) instruction

to set the Write Enable Latch (WEL) bit . This bit

is returned to its reset state by the following

events:

– Power-up

– Write Disable (WRDI) instruction completion

– Write Status Register (WRSR) instruction

completion

– Page Program (PP) instruction completion

– Sector Erase (SE) instruction completion

– Bulk Erase (BE) instruction completion

s

The Block Protect (BP1, BP0) bits allow part of

the memory to be configured as read-only. This

is the Software Protected Mode (SPM).

s

The Write Protect (W) signal, in co-operation

with the Status Register Write Disable (SRWD)

bit, allows the Block Protect (BP1, BP0) bits and

Status Register Write Disable (SRWD) bit to be

write-protected. This is the Hardware Protected

Mode (HPM).

s

In addition to the low power consumption

feature, the Deep Power-down mode offers

extra software protection from inadvertant

Write, Program and Erase instructions, as all

instructions are ignored except one particular

instruction (the Release from Deep Power-

down instruction).

Table 2. Protected Area Sizes

Note: 1. The device is ready to accept a Bulk Erase instruction if, and only if, both Block Protect (BP1, BP0) are 0.

Status Register

Content

Memory Content

BP1 Bit

BP0 Bit

Protected Area

Unprotected Area

0

0

none

All sectors (Sectors 0 and 1)

0

1

No protection against Page Program (PP) and Sector Erase (SE)

All sectors (Sectors 0 and 1) protected against Bulk Erase (BE)

1

0

1

1

All sectors (Sectors 0 and 1)

none