ver. 2.8

12/01/12

8

ES51970(6000counts)

DMM Analog front end with Inrush

Function Description

1.

MPU serial I/O function overview

1.1 Introduction

ES51970 configures a 3-wire serial I/O interface to external microprocessor unit (MPU).

The SDATA pin is bi-directional and SCLK & DATA_NEW are unilateral. The SDATA pin

is configured by open-drain circuit design. The DATA_NEW is used to check the data

buffer of ADC ready or not. When the ADC conversion cycle is finished, the DATA_NEW

pin will be pulled high until MPU send a valid read command to ES51970. After the first ID

byte is confirmed, the DATA_NEW will be driven to low until the next ADC conversion

finished again.

The data communication protocol is shown below. The write protocol is configured by an

ID byte with four command bytes. The read protocol is configured by an ID byte with ten

data bytes.

Write command:

ID byte, Write control byte1, Write control byte2, Write control byte3, Write control byte4

Read command:

ID byte, Read data byte1, Read data byte2 ~ Read data byte9, Read data byte10

1 1 0

0

0 1

WRITE

A

C

K

A

C

K

A

C

K

A

C

K

START BIT

STOP BIT

0

B

U

Z

A

C

K

1 1 0

0

0 1

WRITE

A

C

K

A

C

K

A

C

K

A

C

K

START BIT

STOP BIT

0

B

U

Z

A

C

K

A

C

K

1 1 0

0

0 1

A

C

K

START BIT

STOP BIT

A

C

K

A

C

K

A

C

K

A

C

K

N

A

K

READ

1

B

U

Z

1 1 0

0

0 1

A

C

K

START BIT

STOP BIT

A

C

K

A

C

K

A

C

K

A

C

K

N

A

K

READ

1

B

U

Z

SCLK

SDATA

DATA_NEW

ADC data ready

Next ADC data ready

1

1

0

0

1

0

ID code confirmed

1

Read command

Start bit

Stop bit

ID code

SCLK

SDATA

DATA_NEW

ADC data ready

Next ADC data ready

1

1

0

0

1

0

ID code confirmed

1

Read command

Start bit

Stop bit

ID code