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Q MICROCHIP

MCP3423

Evaluation Board

User’s Guide

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6‘ MICROCHIP

MCP3423 EVALUATION BOARD

USER’S GUIDE

Table of Contents

Preface ........................................................................................................................... 1

Introduction............................................................................................................ 1

Document Layout .................................................................................................. 1

Conventions Used in this Guide ............................................................................ 2

Recommended Reading........................................................................................ 3

The Microchip Web Site ........................................................................................ 3

Customer Support ................................................................................................. 3

Document Revision History ................................................................................... 3

Chapter 1. Quick Start Instructions

1.1 Introduction ..................................................................................................... 5

1.2 Description of the MCP3423 Evaluation Board .............................................. 5

1.3 Getting Started with PICkit Serial Analyzer .................................................... 6

1.4 Experiment for CH2 ...................................................................................... 22

Appendix A. Schematic and Layouts

A.1 Introduction .................................................................................................. 23

A.2 Board – Schematic ....................................................................................... 24

A.3 Board – Top Laer ......................................................................................... 25

A.4 Board – Top Metal Layer ............................................................................. 26

A.5 Board – Bottom Layer .................................................................................. 27

A.6 Board – Bottom Metal Layer ........................................................................ 28

Appendix B. Bill of Materials (BOM)

Worldwide Sales and Service .................................................................................... 30

MCP3423 Evaluation Board User’s Guide

NOTES:

6‘ MICROCHIP

MCP3423 EVALUATION BOARD

USER’S GUIDE

Preface

INTRODUCTION

This chapter contains general information that will be useful to know before using the

MCP3423 Evaluation Board. Items discussed in this chapter include:

• Document Layout

• Conventions Used in this Guide

• Recommended Reading

• The Microchip Web Site

• Customer Support

• Document Revision History

DOCUMENT LAYOUT

This document describes how to use the MCP3423 Evaluation Board as a

development tool to emulate and debug firmware on a target board. The manual layout

is as follows:

•Chapter 1. “Quick Start Instructions” – this chapter provides an overview of the

MCP3423 Evaluation Board and instructions on how to use the MCP3423

Evaluation Board with the PICkit Serial Analyzer.

•Appendix A. “Schematic and Layouts” – shows the schematic and layout

diagrams for the MCP3423 Evaluation Board.

•Appendix B. “Bill of Materials (BOM)” – lists the parts used to build the

MCP3423 Evaluation Board.

NOTICE TO CUSTOMERS

All documentation becomes dated, and this manual is no exception. Microchip tools and

documentation are constantly evolving to meet customer needs, so some actual dialogs

and/or tool descriptions may differ from those in this document. Please refer to our web site

(www.microchip.com) to obtain the latest documentation available.

Documents are identified with a “DS” number. This number is located on the bottom of each

page, in front of the page number. The numbering convention for the DS number is

“DSXXXXXA”, where “XXXXX” is the document number and “A” is the revision level of the

document.

For the most up-to-date information on development tools, see the MPLAB® IDE on-line help.

Select the Help menu, and then Topics to open a list of available on-line help files.

MPLABW Hle>Sa vs

MCP3423 Evaluation Board User’s Guide

CONVENTIONS USED IN THIS GUIDE

This manual uses the following documentation conventions:

DOCUMENTATION CONVENTIONS

Description Represents Examples

Arial font:

Italic characters Referenced books MPLAB® IDE User’s Guide

Emphasized text ...is the only compiler...

Initial caps A window the Output window

A dialog the Settings dialog

A menu selection select Enable Programmer

Quotes A field name in a window or

dialog

“Save project before build”

Underlined, italic text with

right angle bracket

A menu path File>Save

Bold characters A dialog button Click OK

A tab Click the Power tab

N‘Rnnnn A number in verilog format,

where N is the total number of

digits, R is the radix and n is a

digit.

4‘b0010, 2‘hF1

Text in angle brackets < > A key on the keyboard Press <Enter>, <F1>

Courier New font:

Plain Courier New Sample source code #define START

Filenames autoexec.bat

File paths c:\mcc18\h

Keywords _asm, _endasm, static

Command-line options -Opa+, -Opa-

Bit values 0, 1

Constants 0xFF, ‘A’

Italic Courier New A variable argument file.o, where file can be

any valid filename

Square brackets [ ] Optional arguments mcc18 [options] file

[options]

Curly brackets and pipe

character: { | }

Choice of mutually exclusive

arguments; an OR selection

errorlevel {0|1}

Ellipses... Replaces repeated text var_name [,

var_name...]

Represents code supplied by

user

void main (void)

{ ...

}

Preface

RECOMMENDED READING

This user's guide describes how to use MCP3423 Evaluation Board. Other useful

documents are listed below. The following Microchip document is available and

recommended as supplemental reference resources:

PICkit™ Serial Analyzer User’s Guide (DS51647)

Consult this document for instructions on how to use the PICkit Serial Analyzer

hardware and software.

MCP3422/3/4 Data Sheet, “18-Bits, Multi-Channel Delta-Sigma Analog-to-Digital

Converter with I2C Interface and On-Board Reference” (DS22088)

This data sheet provides detailed information regarding the MCP3423 product family.

THE MICROCHIP WEB SITE

Microchip provides online support via our web site at www.microchip.com. This web

site is used as a means to make files and information easily available to customers.

Accessible by using your favorite Internet browser, the web site contains the following

information:

•Product Support – Data sheets and errata, application notes and sample

programs, design resources, user’s guides and hardware support documents,

latest software releases and archived software

•General Technical Support – Frequently Asked Questions (FAQs), technical

support requests, online discussion groups, Microchip consultant program

member listing

•Business of Microchip – Product selector and ordering guides, latest Microchip

press releases, listing of seminars and events, listings of Microchip sales offices,

distributors and factory representatives

CUSTOMER SUPPORT

Users of Microchip products can receive assistance through several channels:

• Distributor or Representative

• Local Sales Office

• Field Application Engineer (FAE)

• Technical Support

Customers should contact their distributor, representative or field application engineer

(FAE) for support. Local sales offices are also available to help customers. A listing of

sales offices and locations is included in the back of this document.

Technical support is available through the web site at: http://support.microchip.com.

DOCUMENT REVISION HISTORY

Revision A (November 2008)

• Initial Release of this Document.

MCP3423 Evaluation Board User’s Guide

NOTES:

6‘ MICROCHIP

MCP3423 EVALUATION BOARD

USER’S GUIDE

Chapter 1. Quick Start Instructions

1.1 INTRODUCTION

The following sections provide an overview of the MCP3423 Evaluation Board and

demonstrate how to use it with the PICkit™ Serial Analyzer (P/N: DV164122).

The following topics are covered:

• Description of the MCP3423 Evaluation Board

• How to use MCP3423 Evaluation Board with the PICkit Serial Analyzer

1.2 DESCRIPTION OF THE MCP3423 EVALUATION BOARD

The MCP3423 Evaluation Board (P/N MCP3423EV) contains a MCP3423 18-Bit ΔΣ

Analog-to-Digital Converter (ADC). The MCP3423 is a 2-channel 18 bit delta-sigma

ADC device with various configuration options. The board has analog input connection

pads and various test pads.

The user can connect inputs and test the conversion results using the PICkit Serial

Analyzer and its PC graphic user interface (GUI). The MCP3423 Evaluation Board has

the following interfaces:

• PICkit Serial Analyzer (P/N: DV164122) for writing configuration register bits and

reading the conversion data.

The board has test points for SDL, SDA, and analog inputs. By connecting an

oscilloscope to these test points, the user can examine the data communications

through the I2C™ bus line and observe the resulting conversion output. Refer to

Appendix A. “Schematic and Layouts”.

1.2.1 I2C Address Bits and A0 Address Bit Selection

The I2C device code and address bits of the MCP3423 device are:

• Device Code: ‘1101’

• A2, A1, A0 Address Bits: determined by the JP2 (Adr1 pin) and JP3 (Adr0 pin).

• See Table 1-1 for the I2C Device Address bits and JP2 and JP3 connections.

Note: The user can use this board without the PICkit Serial Analyzer as long as

the VDD, SCL, and SDA are provided through J1 connector. This Evaluation

Board does not include MCU.

‘1 7‘ MICPOCHIP

MCP3423 Evaluation Board User’s Guide

FIGURE 1-1: Front View of the MCP3423 Evaluation Board.

1.3 GETTING STARTED WITH PICKIT SERIAL ANALYZER

Figure 1-1 shows the MCP3423 Evaluation Board, and Figure 1-2 shows the

MCP3423 and PICkit Serial Analyzer.

The following describes how to use them together:

1. Connect the MCP3423 Evaluation Board’s 6-pin socket to the PICkit Serial

Analyzer as shown in Figure 1-2.

2. Connect the oscilloscope probes to the SCL and SDA test pins (optional).

3. VDD Selection: You can use the VDD from the PICkit Serial Analyzer or use your

own external VDD. The JP1 connector selects the VDD path.

(a) Connect JP1, if using VDD from PICkit Serial Analyzer.

(b) Disconnect JP1 and apply VDD at VDD1 pin, if you are using an external VDD.

4. Address bit selection using JP2 and JP3 connectors.

The I2C device code and address bits of the MCP3423 device are:

• MCP3423 I2C device code: ‘1101’

• A2, A1, A0 Address Bits: determined by the JP2 (Adr1 pin) and JP3 (Adr0 pin)

• The JP2 and JP3 connectors are external address bit selections. Connect these

pins to VSS, VDD, float, or connect any arbitrary voltage

• See Table 1-1 for the I2C Device Address bits and JP2 and JP3 connections

5. Connecting VDD: LED D1 turns on when VDD is applied. The PICkit Serial

Analyzer will provide VDD automatically, if it is connected to the PC. Make sure

LED D1 turns on, when you execute the command using the PICkit Serial

Analyzer.

Quick Start Instructions

6. Connecting the analog inputs: If you need to measure a single-ended input,

connect the unused pin (example, CHx-) to VSS.

•Connecting the inputs: The MCP3423 Evaluation Board has input pads for two

analog input channels. You can connect all inputs at the same time and multiplex

the input channel using configuration register settings. You can also leave the

unused channel inputs floating.

7. Use the PICkit Serial Analyzer PC GUI to send I2C write and read commands.

TABLE 1-1: I2C ADDRESS BITS VS. JP2 AND JP3 CONNECTORS

CAUTION

Each analog input pin has an ESD diode. Certain input conditions can damage the

device. Please use the following conditions:

(a) Do not apply an input greater than the input range specified by the MCP3423 Data

Sheet.

(b)Apply the input signal after VDD is powered-up.

I2C Device Address

Bits JP2 (Adr1 Pin) JP3 (Adr0 Pin)

1101 000 W/R Connected to VSS Connected to VSS

1101 001 W/R Connected to VSS Float

1101 010 W/R Connected to VSS Connected to VDD

1101 100 W/R Connected to VDD Connected to VSS

1101 101 W/R Connected to VDD Float

1101 110 W/R Connected to VDD Connected to VDD

1101 011 W/R Float Connected to VSS

1101 111 W/R Float Connected to VDD

1101 000 W/R Float Float

Note 1: W/R bit = “0” for writing, “1” for reading.

2: Float: (a) Leave pin without connecting to anything, or (b) apply Addr_Float voltage.

See MCP3423 Data Sheet for more details.

MCP3423 Evaluation Board User’s Guide

FIGURE 1-2: MCP3423 Evaluation Board with the PICkit Serial Analyzer.

1.3.1 PICkit Serial Analyzer PC Software Setup for the MCP3423

Evaluation Board

The following steps describe how to set up and use the PICkit Serial Analyzer PC

Graphic User Interface (GUI).

1. Install the PICkit Serial Analyzer software onto your personal computer (PC).

2. Connect the USB cable between the PICkit Serial Analyzer and the PC.

3. Run the PICkit Serial PC Software - it will open to the following GUI:

PICkit Serial Analyzer

MCP3423 Evaluation Board

USB Cable

Personal

Computer

Connected between the

PICkit Serial Analyzer

and Personal Computer

Sensor Input

Connectors

Cunhgu rallan Wizar d Welcome To The '53 Pleit Serial Analyzer Configuration Wizard The loiiowing step: Wlii guide you through the setup of the FEM Serial Analyzer E. :5; n- Cancel Coniigulalian Wizard Communicalion Mode — Page 1 014 Choose which mode ol communication you Wish to use G |2l2 Master F 3 Pl M aster P USAHT Async F USAHT Sync Masts! < back="" next=""> Cancel

Quick Start Instructions

FIGURE 1-3: PICkit Serial Analyzer Configuration Window welcome window.

Click the Next button and follow the instructions.

4. Select the Communication Mode type: I2C Master, and click the Next button.

FIGURE 1-4: Step 1 - Communication Mode selection.

Configuralio n Wizal d Communicaliun Speed - Page 2 of 4 Selecl your IZC communication speed Communication speed may also be l” 100 kHz adiusled by using the 'Conllgure (3‘ M ode' page lvom lhe 'PI Ekit S enal 400 kH z Analyzel' menu dvopdown allel completing lhe Configuration leald < back="" next=""> Cancel

MCP3423 Evaluation Board User’s Guide

5. In the new window, select “100 kHz” or “400 kHz”. Either one will be fine. Click

the Next button.

FIGURE 1-5: Step 2 - I2C Communication Speed window.

Note: The MCP3423 device supports the I2C bus data rate up to 3.4 MHz, but the

current version of the PICkit Serial Analyzer supports the I2C bus data rate

up to 400 kHz only.

Device Pullups - Page 3 at 4 Do you need to enable pullups rm ynur dawm Enable Pdup: F Yes (3 No < back="" next=""> Cancel

Quick Start Instructions

6. In the Device Pullups window, select No on “Enable Pull-ups” and click the Next

button.

FIGURE 1-6: Step 3 - Device Pullups window.

7. In this step, you have to select the VDD voltage of the MCP3423 Evaluation

Board, then click the Next button.

Case 1: When you use VDD from the PICkit Serial Analyzer:

If you choose PICkit Serial will power your device and 5 Volts as shown in

Figure 1-7, the MCP3423 Evaluation Board is powered by the 5V DC from the

PICkit Serial Analyzer through the JP1 jumper. In this case, make sure that the

JP1 jumper on the MCP3423 Evaluation Board is connected.

Case 2: When you use your own VDD:

You can also provide your own VDD voltage by applying a VDD voltage at VD1

test point. In this case, make sure that the JP1 jumper is disconnected.

Note: The MCP3423 Evaluation Board has its own pull-up resistors.

Configuration Wizard Voltage Source - Page 4 014 Does F‘leit Serial need to power your device? Voltage PICkit Serial will I7 V power my dewce ll Pleit Serial will Dowel your 3 5 Volt device, select the checkbox to p mhe, the left, then determine your voltage. 5.0! < back="" next=""> Cancel nfiguratinn Wiz rd You're Done! Pies: ‘DK' to complete the Configuration Wizard 7 Do not show |his wizard on :tartup again Wizard may be accessed anytime tram menu diDpdDwn Pleit SeiialAnalyzei -> Run Cunliguralion Wizard _I_IL

MCP3423 Evaluation Board User’s Guide

FIGURE 1-7: Step 4 - Voltage Source selection window.

8. Click the OK button. You have made all of the PICkit Serial Analyzer

Configuration Setups. You are now ready to program the MCP3423 Evaluation

Board using the PICkit Serial Analyzer.

FIGURE 1-8: Configuration Wizard - Finishing step.

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Quick Start Instructions

1.3.2 Creating Script Files

In order to make a communication connection between the PICkit Serial Analyzer and

the MCP3423 Evaluation Board, a script file is needed. Figure 1-9 shows how to create

script files and how to use them.

• In the PICkit Serial Analyzer window, select from the menu Communications>

Script>Script Builder .

FIGURE 1-9: Creating a script file with Script Builder.

1.3.2.1 CREATING SCRIPT FILE FOR CONFIGURATION BYTE WRITING

1. Click on WriteBlockAddrA8 in “Example I2C Scripts” column.

This will result in filling in the spaces under the “Script Detail” column.

You can now modify the “Script Detail” column parameters by right-clicking the

mouse.

How to modify the parameters box in Script Details:

1. Under the “Script Detail” box, select the item in the parameter box.

2. Right click the mouse button and an option box appears to the right of your

selection. These are the options available for the parameter selected.

3. Select the desired option and delete or insert the parameter box.

4. Keep the parameters in order as shown in Figure 1-10:

Communications View: Basic Scripl Builder Script N ame ‘ MCP3423_Wrt_EH1 ‘ Save Script Exocule 5 l Communications: Basic Operations Example IZE Scripts FleadAddrAB WriteAddrAS WriteBlockAddrAB FleadB lockAddrAﬁ Demo Boards Reset I l X ‘1 DICkil Serial , IZC Masier Mode Pickit Serial Analyzer UserDefInedTemplates View Window Help Serial Detail lZESTAFlT ‘ izcwnravr 02 x U :er IZC S :ripts M EP3424 GenCalA A M EP342 3_Wrt_EH2 ”DC at Clear Script Del Uxer S Show Array Ell: x lZESTDP lo_se

MCP3423 Evaluation Board User’s Guide

FIGURE 1-10: Modifying parameters in Script Builder window.

4. Change the parameter value:

1. To change value:

• Click this box and type a

new value

2. To delete or Insert a new box:

• Choose the box and right

click the mouse button

for options available

3. Make sure the listed

parameters in “script Detail”

are in the exact order as

shown here.

I2CSTART

I2CWRTBYT

I2CSTOP

Script Detail

This means there are two bytes to send

1st Write Byte: Address byte with W/R bit = 1101-1100

2nd Write Byte: 1001-1100

Note: All six parameters above must be listed in order. The parameter above

marked with * character are not modifiable. Address bits (A2, A1, A0) =

(1,1,0) if both JP2 and JP3 are tied to VDD. You can use different address

bits by rearranging the connectors. See MCP3423 Data Sheet for more

information on address bit sections.

‘1 Pick“ Serial , |2C Master Mode Cornrnunltations Pleit Serial Analyzer Demo Boards User Defined Templates View Window Help View: Basic Communications: Basic Operations Reset Script Builder _ X Example IZE Scripts Script Detail User IZIZ Scripts Script Name HeedAddrAB WSW” . MEP3423_Wrt_CH1 WirteAddrAS WriteBluckAddrAB iZWRTBYT Fl dBl kAddAS Save Script ea 00 r 02 x DC 1: Clear Sclipl lZCSTDP Del User Scripts X S how Array

Quick Start Instructions

FIGURE 1-11: Script file example for I2C Write Command.

1.3.2.2 SAVE THE SCRIPT FILE AND PROGRAMMING THE MCP3423

CONFIGURATION REGISTER

1. Change the 2nd and 3rd data bytes you want in the Script Detail.

2. Type in any script name (i.e., MCP3423_Write) in the space below the “Script

Name” menu.

3. Click Save Script button.

4. Click Execute Script button.

Address Byte

Configuration Byte

(9C)

Note: The “9C” in the configuration byte selects the following options:

- Conversion Mode: Continuous Conversion

- Channel Selection: Channel 1

- Bit Resolution: 18 bits

- Gain Selection: 1x

2 Bytes to send

Note: At this point, the PICkit Serial transmits the I2C Write Command to the

MCP3423 device. The saved file name will appear in “Users I2C Scripts”

column, and can be re-used any time by selecting the file name.

MCP3423 Evaluation Board User’s Guide

5. You can also see the SCL and SDA waveforms using the Oscilloscope.

FIGURE 1-12: I2C Write Command Waveforms for the MCP3423.

Note: When you click on the “Execute Script” menu, the “Busy” LED on the PICkit

Serial Analyzer will momentarily turn on and then turn off. If the LED

remains ON, a communications problem has occurred. Remove the PICkit

Serial Analyzer from your computer and recheck the parameter values

including the order of parameters under the “Script Detail” column, and try

again until the “Busy” LED turns OFF immediately after sending the I2C

command.

Write Command with Address bits Configuration Bits

Zoom-in

Quick Start Instructions

1.3.3 Trouble Shooting: If the device does not acknowledge the

commands

If the device is powered up initially with unstable VDD from the PICKit Serial, there is a

chance that the device can latch a wrong address bits from the external address pins,

and therefore it may not acknowledge the command bytes correctly since the address

bits are not matched. In this case, send a General Call Latch Command after the VDD

is stabilized (after about 20 seconds the PICKit Serial is powered). See the example in

Figure 1-13. Another method is power-up the PICKit Serial first by connecting to the

PC, then insert the MCP3423 EV board to the PICKit Serial about 20 seconds later.

FIGURE 1-13: Examples when the device is not acknowledging the write command. Send the

General Call Latch Command when the VDD is stabilized.

NAK Pulse NAK Pulse

ACK Pulse ACK Pulse

(a) The device

does not

acknowledge the

write command.

(b) Send a

General Call

Latch Command.

now acknowledge

the command.

E \

MCP3423 Evaluation Board User’s Guide

1.3.4 Reading the Conversion Data using the PICkit Serial Analyzer

You can read back the conversion data with the following steps.

1.3.4.1 CREATING SCRIPT FILE TO READ CONVERSION DATA

1. Click on ReadAddrA8 in “Example I2C Scripts” column.

This will result in filling in the spaces under “Script Detail” column.

Now you can modify the parameter boxes (delete or insert) in the “Script Detail”

column with options. The list of options will appear if you right-click the mouse in

the parameter box. You can delete the parameter box or add a new one.

2. Make sure you have the “Script Detail” parameters listed in order as follows:

I2CSTART

I2CWRTBYT

I2CRDBYTNLB

I2CSTOP

Script Detail

This means there is one byte for address

Address byte with W/R bit = 1101-1101

5 bytes to read

Note: All seven parameters above must be listed in order. The parameters above

marked with * character are not modifiable.

Address bits (A2, A1, A0) = (1,1,0) if both JP2 and JP3 are tied to VDD. You

can use different address bits by rearranging the JP1 and JP2 connectors.

See MCP3423 Data Sheet for more information on address bit selections.

ll Plfku ﬁendl IX Masler Made Communications PICHtSenalAnaOyzev DemoBuards UserDefinedTeﬂuﬁates View Window Help View: Basic Communications: Basic Opaauons Reset Sclipl Buildev _ " Exanw IZC Serials Script Detail Use! IZC Sovipts Script Name HeadAdd‘AB IZES TART ‘ MCP3424_GenCaIA A [—MEP3423 Read WnleAddlAB MCP3423_ w.:_ EH1 _ WriteBlockAddlAB IZEM/RTBYT MCP3423 W1! CH2 , R eadBlcckAddlAB [01— Save Scnpl x ‘ Execute Serial 6; [% [IzcsmP—x ‘ Del User Selim: X ‘ Show Array [—x [—x [—x [—x

Quick Start Instructions

FIGURE 1-14: Script File sample to read conversion data.

3. Type in any script name (i.e., MCP3423_Read) in the space below the “Script

Name” menu.

4. Click Save Script button.

5. Click Execute Script button.

6. You can also see the SCL and SDA waveforms using the Oscilloscope.

Requesting

5 Bytes

Address Byte

Note: At this point, the PICkit Serial transmits the I2C Read Command to the