BR34E02NUX-WE2 Ver la hoja de datos (PDF) - ROHM Semiconductor

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BR34E02NUX-WE2

Double-cell Memory for Plug & Play DDR/DDR2 (For memory module) SPD Memory

ROHM Semiconductor 

・The last bit of the stream (R/W…READ/WRITE) determines the operation to be performed.

R/W=0 ････ WRITE (including word address input of Random Read)

R/W=1 ････ READ

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

GND GND VHV

0110

A2 A1 A0

001

R/W

Access to Permanent Set Write

Protect Memory

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 Input

Protect Registor

Input Command

ACK

Address

ACK

Data

ACK

Write

Cycle(tWR)

PSWP, SWP, CWP No ACK

-

No ACK

No ACK

No

In case,

protect by PSWP

-

Page or Byte Write

(00～7Fh)

ACK

WA7～WA0

ACK

D7～D0 No ACK

No

SWP

No ACK

-

No ACK

-

No ACK

No

CWP

ACK

-

ACK

-

ACK

Yes

0

PSWP

ACK

-

ACK

-

ACK

Yes

In case,

protect by SWP

Page or Byte Write

(00～7Fh)

ACK

WA7～WA0

ACK

D7～D0 No ACK

No

SWP

No ACK

-

No ACK

-

No ACK

No

CSP

ACK

-

ACK

-

No ACK

No

1

PSWP

ACK

-

ACK

-

No ACK

No

Page or Byte Write ACK WA7～WA0 ACK D7～D0 No ACK

No

In case,

PSWP, SWP, CWP ACK

-

ACK

-

ACK

Yes

0

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

Yes

Not protect

PSWP, SWP, CWP ACK

-

ACK

-

No ACK

No

1

Page or Byte Write ACK WA7～WA0 ACK D7～D0 No ACK

No

- is Don’t Care

State of Write Protect Registor

Command

ACK Address ACK Data ACK

In case, protect by PSWP PSWP, SWP, CWP No ACK

-

No ACK - No ACK

SWP

No ACK

-

No ACK - No ACK

In case, protect by SWP

CWP

ACK

-

No ACK - No ACK

PSWP

ACK

-

No ACK - No ACK

In case, Not protect

PSWP, SWP, CWP ACK

-

No ACK - No ACK

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