Microchip Technology MCP3421DM-WS Data Sheet

DS22003E-page 28

© 2009 Microchip Technology Inc.

6.1.3

DEVICE COMMUNICATION TEST

The user can test the communication between the
Master (MCU) and the MCP3421 by simply checking
an acknowledge response from the MCP3421 after
sending a read or write command. Here is an example
using 

a)

Set the R/W bit “LOW” in the address byte.

b)

Check the ACK pulse after sending the

address byte.

If the device acknowledges (ACK = 0), then the
device is connected, otherwise it is not
connected.

c)

Send a STOP bit.

  

6.1.4

DIFFERENTIAL AND SINGLE-
ENDED CONFIGURATION

 shows typical connection examples for

differential and single-ended inputs. Differential input
signals are connected to the V

IN

+ and V

IN

- input pins.

For the single-ended input, the input signal is applied to
one of the input pins (typically connected to the V

IN

+

pin) while the other input pin (typically V

IN

- pin) is

grounded. All device characteristics hold for the single-
ended configuration, but this configuration loses one bit
resolution because the input can only stand in
positive half scale. Refer to 

 

1

2

3

4

5

6

7

8

9

SCL

SDA

1

1

0

1 A2 A1 A0 0

Start

Bit

Address Byte

Address bits 

ADC Section

R/W 

Stop

Bit

AC

K

Response 

Device Code 

Input Signal

Input Signal

Sensor

Sensor

Excitation

Excitation

R

1

R

2

V

IN

+

V

IN

-

V

DD

V

IN

+

V

IN

-

V

DD

C

1

C

2

C

1

C

2

 

C

1

: 0.1

µF

, Ceramic Capacitor

C

2

: 10

µF

, Tantalum Capacitor