BU2098F, BU2090F, BU2090FS

Technical Note

7/12

www.rohm.com

2009.06 - Rev.A

© 2009 ROHM Co., Ltd. All rights reserved.

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Write DATA

Send the stave address from master following the start condition (S). This address consists of 7 bits. The left 1 bit (the foot

bit) is fixed “0”. The stop condition (P) is needed to finish the data transferred. But the re-send starting condition (Sr)

enables to transfer the data without STOP (P).

Fig.4 DATA transmit

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Data format

The format is following.

Table 1 for WRITE format

Slave address

A0～A2

Each bit can be defined by the input levels of pins A0～A3.

A3～A6

These 4 bits are fixed.

R/W

“0”

Write Data

D0～D7

Write “1” to D0 makes Q0 pin High-impedance. And write “0” makes Q0 pin

LOW. D[1:7] and Q[1:7] are same as D0 and Q0.

Table 2 for (A2, A1, A0) to SLAVE ADDRESS

A6

A5

A4

A3

A2

A1

A0

Slave address

0

1

1

1

0

0

0

38H

0

1

1

1

0

0

1

39H

0

1

1

1

0

1

0

3AH

0

1

1

1

0

1

1

3BH

0

1

1

1

1

0

0

3CH

0

1

1

1

1

0

1

3DH

0

1

1

1

1

1

0

3EH

0

1

1

1

1

1

1

3FH

S

slave address

R/W

ACK

DATA

ACK

P

S

slave address

R/W

ACK

DATA

ACK

Sr

slave address

R/W

ACK

DATA

ACK

P

S

A6

A5

A4

A3

A2

A1

A0

R/W ACK

D6

D5

D4

D3

D2

D1

D0

D7

ACK

P

SLAVE ADDRESS

WRITE DATA

Fixed for BU2098F

Defined by external pin A0～A2

“0” (Write)

“0” (Write)

“0” (Write)