10. I2C interface

The epc901 supports the following functions by using the I2C interface:

■ Fast I2C (400 kBit/s)

■ 7-bit addressing

■ Slave (epc901 is always the slave)

■ Supported functions are software reset, read, write, read the device address

Clock stretching and other uses of I2C bus are not supported. The register list which can be accessed by the I2C interface are listed in

section 10.3. All registers can be accessed directly except the test mode registers.

10.1. I2C communication

10.1.1. Device addressing

CS0

L

M

H

CS1

L

0000

0001

0011

M

0100

0101

0111

H

1100

1101

1111

The LSB of the device addressing is used to select the communication direction:

0

0

1

A

3

A

2

A

1

A

0

0

Write access

The bus protocol in the following sections uses the following notation:

Symbol

Function

S

START

P

STOP

A

ACK

N

NACK

Shaded

Master

Unshaded

Slave (epc901

10.1.2. Single-byte write

P

Device address

A

S 0 0 1

0

Register address

A

Data

A

10.1.3. Multi-byte write

During a multi-byte write operation the master transmits the device address and the address of the first register to be written. All subse -

quent bytes until STOP are interpreted as write data packets.

Register address

S

P

A

Write data 0

A

Write data 1

A

Write data n

A

A

0 0 1

0

Device address

Registers reside in a non-consecutive address space. Writing to a unused address will fail silently (no error feedback).

© 2016 ESPROS Photonics Corporation

Characteristics subject to change without notice

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