[2SMPB-02E] Datasheet Rev.05(Jun.,2017)

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Copyright 2017 OMRON Corporation. All Rights Reserved.

4.5 I²C Protocol

(1) I²C Slave Address

The 2SMPB-02 module I²C slave address is shown below.

SDO

I²C Slave

Address (7bits)

Bit

bit7

bit6

bit5

bit4

bit3

bit2

bit1

bit0

Add[6]

Add[5]

Add[4]

Add[3]

Add[2]

Add[1]

Add[0]

R/W

High(1)

56h+R/W

Value

1

0

1

0

1

1

0

1/0

Low(0)

70h+R/W

Value

1

1

1

0

0

0

0

1/0

For example, in case of SDO=Low (0),

Write Access ：

Please set LSB of slave address as “0”, then the address is E0h(1110_0000b). (70h<<1+WR(0))

Read Access ：

Please set LSB of slave address as “1”, then the address is E1h(1110_0001b). (70h<<1+RD(1))

(2) I²C Access Protocol Examples

Symbol

・

START

： START condition

・

STOP

： STOP condition

・

Re-START

： Re-START condition for Read

・

SACK

： Acknowledge by Slave

・

MACK

： Acknowledge by Master

・

MNACK： Not Acknowledge by Master

(3) Register Write Access Protocol

After the START condition, a Device Address is sent. This address is seven bits long followed by an eighth bit which is a

data direction bit.

A ‘zero’ indicates a transmission “WRITE”. After that, the register address and the writing data shall be

one set and it should be continuously transmitted until a STOP condition. A data transfer is always terminated by a STOP

condition generated by the master.

※Black characters : Master

(4) Register Read Access Protocol

After a START condition, the Device Address with WRITE sign

(“0”) and Word Address intended to read a fir

st data are transmitted. Next,

“STOP–START” or “Re-START” condition are transmitted by the master. After th

at, Device Address with READ sign (

“1”) is transmitted by the master. Then, the slave will output the first dat

a that is intended to read. In case of incrementing Register Address automatically, the slave will output the d

ata repeatedly until NACK is input by the master. If Register Address becomes "0xFF", please continue to out

put "0xFF." Below example shows 3 bytes reading method from "0xFA" register.

SCL

7

6

5

4

3

2

1

0

SDA

Start

7

6

5

4

3

2

1

0

7

6

5

4

3

2

1

0

7

6

5

4

3

2

1

0

7

6

5

4

3

2

1

0

DeviceAddress

0

ACK

Register Address

ACK

ACK

・・・

Register Address

ACK

Write Data

ACK

・・・

Write Data

ACK

Stop

SCL

7

6

5

4

3

2

1

0

7

6

5

4

3

2

1

0

SDA

Start

7

6

5

4

3

2

1

0

7

6

5

4

3

2

1

0

Start

7

6

5

4

3

2

1

0

7

6

5

4

3

2

1

0

DeviceAddress

0

ACK

Register Address"0xFA"

ACK

DeviceAddress

1

ACK

Read Data of "0xFA"

ACK

Stop

Read Data of "0xFB"

ACK

Read Data of "0xFC"

NACK