BR34E02FVT-3TR Ver la hoja de datos (PDF) - ROHM Semiconductor

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BR34E02FVT-3TR

Memory for Plug & Play DDR2/DDR3 SPD Memory (for Memory Modules)

ROHM Semiconductor 

BR34E02FVT-3,BR34E02NUX-3

Technical Note

Slave Address Set Pin Device Type Device Address Read Write Mode

Access Area

A2

A1

A0

1010

A2 A1 A0

R/W

2kbit Access to Memory

A2

A1

A0

A2 A1 A0

R/W

Access to Permanent Set Write

Protect Memory

GND GND VHV

0110

001

R/W

Access to Set Write Protect Memroy

GND Vcc VHV

011

R/W

Access to Clear Write Protect Memory

○WRITE PROTECT PIN(WP)

When WP pin set to Vcc (H level), write protect is set for 256 words (all address). When WP pin set to GND (L level),

it is enable to write 256 words (all address).

If permanent protection is done by Write Protect command, lower half area (00～7Fh address) is inhibited writing

regardless of WP pin state.

WP pin has a Pull-Down resistor. Please be left unconnected or connect to GND when WP feature is not in use.

○Confirm Write Protect Resistor by ACK

According to state of Write Protect Resistor, ACK is as follows.

State of Write WP

Protect Registor Input

Input Command

ACK

Address

ACK

Data

ACK

Write

Cycle(tWR)

In case,

protect by PSWP

-

PSWP,SWP,CWP

Page or Byte Write

(00～7Fh)

No ACK

-

No ACK

ACK WA7～WA0 ACK

-

D7～D0

SWP

No ACK

-

No ACK

-

0

In case,protect by

SWP

CWP

PSWP

Page or Byte Write

(00～7Fh)

SWP

ACK

-

ACK

ACK

-

ACK

ACK WA7～WA0 ACK

No ACK

-

No ACK

-

-

D7～D0

-

CSP

1

PSWP

ACK

-

ACK

-

ACK

-

ACK

-

Page or Byte Write ACK WA7～WA0 ACK D7～D0

In case,

Not protect

0 PSWP, SWP, CWP

Page or Byte Write

PSWP, SWP, CWP

1

Page or Byte Write

ACK

ACK

ACK

ACK

-

WA7～WA0

-

WA7～WA0

ACK

ACK

ACK

ACK

-

D7～D0

-

D7～D0

Acknowledge when writing data or defining the write-protection(instructions with R/W bit=0)

No ACK

No

No ACK

No

No ACK

No

ACK

Yes

ACK

Yes

No ACK

No

No ACK

No

No ACK

No

No ACK

No

No ACK

No

ACK

Yes

ACK

Yes

No ACK

No

No ACK

No

- is Don’t Car

State of Write Protect Registor

Command

ACK

Address ACK

In case, protect by PSWP

PSWP, SWP, CWP

No ACK

-

No ACK

SWP

No ACK

-

No ACK

In case, protect by SWP

CWP

ACK

-

No ACK

PSWP

ACK

-

No ACK

Case, Not protect

PSWP, SWP, CWP

ACK

Acknowledge when reading data the write-protection(instructions with R/W bit=1)

-

No ACK

Data

-

-

-

-

-

ACK

NoACK

No ACK

No ACK

No ACK

No ACK

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8/19

2011.11 - Rev.A

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