DIO1412

Version 1.0, Jul 2024

www.dioo.com

© 2024 DIOO MICROCIRCUITS CO., LTD.

15

11.2. SMBus protocol

The DIO1412 supports various kind of byte protocols: Send bite, Read byte, Write byte, Receive byte and Alert

response address as valid protocols.

(1) Write byte: Writing one byte of data to the registers.

(2) Read byte: Reading one byte of data from the registers.

(3) Send byte: Setting the internal address register pointer to the correct address location. Noted that no data is

transferred during the Send byte protocol.

(4) Receive byte: Reading data from a register when the internal register address pointer is at the correct

location via Send byte. This is used for consecutive reads of the same register.

(5) Alert response address: the

_____

ALERT pin output can be interpreted as interrupt or as an SMBus Alert by the

host. When the

_____

ALERT pin is asserted, the host will send the Alert Response Address (ARA) to the general

address of 0001_100xb. The DIO1412 will respond to the ARA in two steps: send the slave address of DIO1412.

Then the channel mask bit will be set and the

_____

ALERT pin will be deasserted.

Write Byte Protocol

Start

Slave

Address

WR

ACK (1)

Register

Address

ACK (1)

Register

Data

ACK (1)

Stop

1 -> 0

YYYY_YYY

0

0

XXh

0

XXh

0

0 ->1

Read Byte Protocol

Start

Slave

Address

WR

ACK (1)

Register

Address

ACK (1)

Start

Slave

Address

RD

ACK (1)

Register

Data (1)

NACK

Stop

1 -> 0

YYYY_

YYY

0

0

XXh

0

1 -> 0

YYYY_

YYY

1

0

XXh

1

0 ->1

Send Byte Protocol

Start

Slave Address

WR

ACK (1)

Register Address

ACK (1)

Stop

1 -> 0

YYYY_YYY

0

0

XXh

0

0 ->1

Receive Byte Protocol

Start

Slave Address

RD

ACK (1)

Register Data (1)

NACK

Stop

1 -> 0

YYYY_YYY

1

0

XXh

1

0 ->1

Alert Response Address Protocol

Start

Alert Response

Address

RD

ACK (1)

Device Address (1)

NACK

Stop

1 -> 0

0001_100

1

0

YYYY_YYY

1

0 ->1

Note:

(1) Date is sent to the host.