AS3682

Data Sheet

Serial Interface

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Revision 2.21

34 - 43

Figure 18. Complete Data Transfer

Figure 19. Byte Write

Figure 20. Page Write

Byte Write and Page Write are used to write data to the slave.

The transmission begins with the START condition, which is generated by the master when the bus is in IDLE state

(the bus is free). The device-write address is followed by the word address. After the word address any number of data

bytes can be send to the slave. The word address is incremented internally, in order to write subsequent data bytes on

subsequent address locations.

For reading data from the slave device, the master has to change the transfer direction. This can be done either with a

repeated START condition followed by the device-read address, or simply with a new transmission START followed by

the device-read address, when the bus is in IDLE state. The device-read address is always followed by the 1st register

byte transmitted from the slave. In Read Mode any number of subsequent register bytes can be read from the slave.

The word address is incremented internally.

The following diagrams show the various read formats available.

Figure 21. Random Read

Random Read and Sequential Read are combined formats. The repeated START condition is used to change the

direction after the data transfer from the master.

The word address transfer is initiated with a START condition issued by the master while the bus is idle. The START

condition is followed by the device-write address and the word address.

S

Start

Condition

Address

R/W

ACK

Data

ACK

Data

ACK

Stop

Condition

P

SDA

SCL

1-7

8

9

1-7

89

1-7

8

9

S

DA

W A

WA

A

reg_data

A P

Write Register

WA++

S

DA

W A

WA

A

reg_data 1

A

reg_data 2

A

…

reg_data n

AP

Write Register

WA++

Write Register

WA++

Write Register

WA++

SDA

W A

WA

A Sr

DA

R A

data

N P

Read Register

WA++

WA++