RT5744/RT5746

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is a registered trademark of Richtek Technology Corporation.

DS5744/DS5746-00

November

2023

www.richtek.com

21

I2C Interface

The all series of RT5744 and RT5746 are able to support fast mode I2C interface (bit rate 400kb/s), and different

parts have their own slave address. For example, the default I2C slave address of the RT5744A is 7'b1010010. The

write or read bit stream (N

≥ 1) is shown below:

S

0

1

A

P

LSB

MSB

A

Assume Address = m

Data for Address = m

Data for Address = m + N - 1

A

Data for Address = m + 1

S

0

P

Assume Address = m

Data for Address = m

Data for Address = m + N - 1

Data for Address = m + 1

Sr

Slave Address

Register Address

Slave Address

Data 1

R/W

R/W

Data N

LSB

MSB

A

A

A

A

A

A

A

A

Read N bytes from RT5744

LSB

MSB

Data 2

Data N

LSB

MSB

LSB

Slave Address

Register Address

Data 1

Data 2

MSB

MSB

LSB

Write N bytes to R5744

Driven by Master,

Driven by Slave (RT5744),

Start,

Repeat Start

Stop,

S

Sr

P

SDA

SCL

tF

tLOW

tHD,STA

tHD,DAT

tHIGH

tSU,DAT

tSU,STA

tHD,STA

tSP

tBUF

tSU,STO

P

S

tR

Sr

S

tF

tR

Figure 4. I2C Read and Write Stream and Timing Diagram

The RT5744 and RT5746 also support High-speed mode (bit rate up to 3.4Mb/s) with access code 08H. Figure 5

and Figure 6 show detailed transfer format. Hs-mode can only commence after the following conditions (all of which

are in F/S-mode):

⚫

START condition (S)

⚫

8-bit master code (00001xxx)

⚫

Not-acknowledge bit ( A )