AS3693B

austriami crosyst ems

www.austriamicrosystems.com

Revision 1.21 / 2011-09-30

20 - 32

7.8

Digital interface

The AS3693B can be controlled with two types of interfaces.

7.8.1 I2C interface

7.8.1.1 Feature List

•

Fast-mode capability (max. SCL-frequency is 400 kHz)

•

Write formats:

Single-Byte-Write, Page-Write

•

Read formats:

Current-Address-Read, Random-Read, Sequential-Read

•

SDA input delay and SCL spike filtering by integrated RC-components

7.8.1.2 Transfer Formats

Figure 1 – I

S

DW

A

WA

A

reg_data

A P

write register,

WA++

S

START condition after STOP

Sr

repeated START

DW

device address for write

DR

device address for read

WA

word address

A

acknowledge

N

no acknowledge

P

stop condition

white field

slave as receiver

grey field

slave as transmitter

WA++

increment word address internally

Figure 2 – I

S

DW

A

WA

A

reg_data 1

A

A

reg_data 2

write register

WA++

P

A

reg_data n

write register

WA++

write register

WA++

…

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 1

be read from the slave. The word address is incremented internally.

The diagrams below show various read formats available:

Figure 3 – I

A

S

DW

A

WA

A

data

N P

read register

WA++

Sr

DR

WA++

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.