MCP3423
Evaluation Board
User’s Guide
© 2008 Microchip Technology Inc.
DS51778A
Note the following details of the code protection feature on Microchip devices:
•
Microchip products meet the specification contained in their particular Microchip Data Sheet.
•
Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the
intended manner and under normal conditions.
•
There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our
knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data
Sheets. Most likely, the person doing so is engaged in theft of intellectual property.
•
Microchip is willing to work with the customer who is concerned about the integrity of their code.
•
Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not
mean that we are guaranteeing the product as “unbreakable.”
Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our
products. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts
allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.
Information contained in this publication regarding device
applications and the like is provided only for your convenience
and may be superseded by updates. It is your responsibility to
ensure that your application meets with your specifications.
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OTHERWISE, RELATED TO THE INFORMATION,
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Trademarks
The Microchip name and logo, the Microchip logo, Accuron,
dsPIC, KEELOQ, KEELOQ logo, MPLAB, PIC, PICmicro,
PICSTART, rfPIC, SmartShunt and UNI/O are registered
trademarks of Microchip Technology Incorporated in the
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FilterLab, Linear Active Thermistor, MXDEV, MXLAB,
SEEVAL, SmartSensor and The Embedded Control Solutions
Company are registered trademarks of Microchip Technology
Incorporated in the U.S.A.
Analog-for-the-Digital Age, Application Maestro, CodeGuard,
dsPICDEM, dsPICDEM.net, dsPICworks, dsSPEAK, ECAN,
ECONOMONITOR, FanSense, In-Circuit Serial
Programming, ICSP, ICEPIC, Mindi, MiWi, MPASM, MPLAB
Certified logo, MPLIB, MPLINK, mTouch, PICkit, PICDEM,
PICDEM.net, PICtail, PIC32 logo, PowerCal, PowerInfo,
PowerMate, PowerTool, REAL ICE, rfLAB, Select Mode, Total
Endurance, WiperLock and ZENA are trademarks of
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countries.
SQTP is a service mark of Microchip Technology Incorporated
in the U.S.A.
All other trademarks mentioned herein are property of their
respective companies.
© 2008, Microchip Technology Incorporated, Printed in the
U.S.A., All Rights Reserved.
Printed on recycled paper.
Microchip received ISO/TS-16949:2002 certification for its worldwide
headquarters, design and wafer fabrication facilities in Chandler and
Tempe, Arizona; Gresham, Oregon and design centers in California
and India. The Company’s quality system processes and procedures
are for its PIC® MCUs and dsPIC® DSCs, KEELOQ® code hopping
devices, Serial EEPROMs, microperipherals, nonvolatile memory and
analog products. In addition, Microchip’s quality system for the design
and manufacture of development systems is ISO 9001:2000 certified.
DS51778A-page ii
© 2008 Microchip Technology Inc.
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
© 2008 Microchip Technology Inc.
DS51778A-page iii
MCP3423 Evaluation Board User’s Guide
NOTES:
DS51778A-page iv
© 2008 Microchip Technology Inc.
MCP3423 EVALUATION BOARD
USER’S GUIDE
Preface
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.
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.
© 2008 Microchip Technology Inc.
DS51778A-page 1
MCP3423 Evaluation Board User’s Guide
CONVENTIONS USED IN THIS GUIDE
This manual uses the following documentation conventions:
DOCUMENTATION CONVENTIONS
Description
Arial font:
Italic characters
Represents
Referenced books
Emphasized text
A window
A dialog
A menu selection
A field name in a window or
dialog
A menu path
MPLAB® IDE User’s Guide
...is the only compiler...
the Output window
the Settings dialog
select Enable Programmer
“Save project before build”
A dialog button
A tab
A number in verilog format,
where N is the total number of
digits, R is the radix and n is a
digit.
A key on the keyboard
Click OK
Click the Power tab
4‘b0010, 2‘hF1
Italic Courier New
Sample source code
Filenames
File paths
Keywords
Command-line options
Bit values
Constants
A variable argument
Square brackets [ ]
Optional arguments
Curly brackets and pipe
character: { | }
Ellipses...
Choice of mutually exclusive
arguments; an OR selection
Replaces repeated text
#define START
autoexec.bat
c:\mcc18\h
_asm, _endasm, static
-Opa+, -Opa0, 1
0xFF, ‘A’
file.o, where file can be
any valid filename
mcc18 [options] file
[options]
errorlevel {0|1}
Initial caps
Quotes
Underlined, italic text with
right angle bracket
Bold characters
N‘Rnnnn
Text in angle brackets < >
Courier New font:
Plain Courier New
Represents code supplied by
user
DS51778A-page 2
Examples
File>Save
Press <Enter>, <F1>
var_name [,
var_name...]
void main (void)
{ ...
}
© 2008 Microchip Technology Inc.
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.
© 2008 Microchip Technology Inc.
DS51778A-page 3
MCP3423 Evaluation Board User’s Guide
NOTES:
DS51778A-page 4
© 2008 Microchip Technology Inc.
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.
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.
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.
© 2008 Microchip Technology Inc.
DS51778A-page 5
MCP3423 Evaluation Board User’s Guide
FIGURE 1-1:
1.3
Front View of the MCP3423 Evaluation Board.
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.
DS51778A-page 6
© 2008 Microchip Technology Inc.
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.
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.
TABLE 1-1:
I2C ADDRESS BITS VS. JP2 AND JP3 CONNECTORS
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:
2:
© 2008 Microchip Technology Inc.
W/R bit = “0” for writing, “1” for reading.
Float: (a) Leave pin without connecting to anything, or (b) apply Addr_Float voltage.
See MCP3423 Data Sheet for more details.
DS51778A-page 7
MCP3423 Evaluation Board User’s Guide
Personal
Computer
USB Cable
Connected between the
PICkit Serial Analyzer
and Personal Computer
PICkit Serial Analyzer
Sensor Input
Connectors
MCP3423 Evaluation Board
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:
DS51778A-page 8
© 2008 Microchip Technology Inc.
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:
© 2008 Microchip Technology Inc.
Step 1 - Communication Mode selection.
DS51778A-page 9
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:
Note:
DS51778A-page 10
Step 2 - I2C Communication Speed window.
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.
© 2008 Microchip Technology Inc.
Quick Start Instructions
6. In the Device Pullups window, select No on “Enable Pull-ups” and click the Next
button.
Note:
The MCP3423 Evaluation Board has its own pull-up resistors.
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.
© 2008 Microchip Technology Inc.
DS51778A-page 11
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:
DS51778A-page 12
Configuration Wizard - Finishing step.
© 2008 Microchip Technology Inc.
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:
© 2008 Microchip Technology Inc.
DS51778A-page 13
MCP3423 Evaluation Board User’s Guide
1.
2.
3.
FIGURE 1-10:
To change value:
• Click this box and type a
new value
To delete or Insert a new box:
• Choose the box and right
click the mouse button
for options available
Make sure the listed
parameters in “script Detail”
are in the exact order as
shown here.
Modifying parameters in Script Builder window.
4. Change the parameter value:
Script Detail
I2CSTART
I2CWRTBYT
02
DC
9C
I2CSTOP
Note:
DS51778A-page 14
*
*
This means there are two bytes to send
1st Write Byte: Address byte with W/R bit = 1101-1100
2nd Write Byte: 1001-1100
*
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.
© 2008 Microchip Technology Inc.
Quick Start Instructions
Bytes to
to send
send
22 Bytes
Address Byte
Configuration Byte
(9C)
Note:
The “9C” in the configuration byte selects the following options:
-
FIGURE 1-11:
Conversion Mode: Continuous Conversion
Channel Selection: Channel 1
Bit Resolution: 18 bits
Gain Selection: 1x
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.
Note:
© 2008 Microchip Technology Inc.
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.
DS51778A-page 15
MCP3423 Evaluation Board User’s Guide
5. You can also see the SCL and SDA waveforms using the Oscilloscope.
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.
Zoom-in
Zoom-in
Write Command with Address bits
FIGURE 1-12:
DS51778A-page 16
Configuration Bits
I2C Write Command Waveforms for the MCP3423.
© 2008 Microchip Technology Inc.
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.
(a) The device
does not
acknowledge the
write command.
NAK Pulse
NAK Pulse
(b) Send a
General Call
Latch Command.
(c) The device
now acknowledge
the command.
ACK Pulse
ACK Pulse
FIGURE 1-13:
Examples when the device is not acknowledging the write command. Send the
General Call Latch Command when the VDD is stabilized.
© 2008 Microchip Technology Inc.
DS51778A-page 17
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
1.
CREATING SCRIPT FILE TO READ CONVERSION DATA
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:
Script Detail
I2CSTART
I2CWRTBYT
01
DD
I2CRDBYTNLB
5
I2CSTOP
Note:
DS51778A-page 18
*
*
*
This means there is one byte for address
Address byte with W/R bit = 1101-1101
5 bytes to read
*
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.
© 2008 Microchip Technology Inc.
Quick Start Instructions
Address Byte
Requesting
5 Bytes
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.
Note:
At this point, the PICkit Serial transmits the I2C Read 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.
6. You can also see the SCL and SDA waveforms using the Oscilloscope.
Note:
© 2008 Microchip Technology Inc.
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.
DS51778A-page 19
MCP3423 Evaluation Board User’s Guide
Requesting
5 Bytes
Reading Data
using a Read Command
5th Byte: Repeated Byte for Configuration byte
4th byte: Configuration Byte (note that RDYbit is “0”)
3rd byte: Data Byte
2nd byte: Data Byte
1st byte: Data Byte
Results:
Output code:
F907 in hex ( = 63751 in decimal)
Output Voltage=
15.625 μV ( LSB )
63751 × -------------------------------------------- = 0.996 Volts with PGA = 1
PGA
Note that if the differential input voltage is negative (CH- > CH+), the MSB of the first byte will be "1". In this case, the
voltage is calculated after converting the output code to 2's complement and then multiply the LSB.
See Section 4.9 of the MCP3423 Data Sheet (DS22088) for more information.
FIGURE 1-15:
Reading Conversion Results: Note that the Input = 0.996V is applied to CH1. The
reading indicates the measured value is 0.996 Volts.
DS51778A-page 20
© 2008 Microchip Technology Inc.
Quick Start Instructions
Zoom-in
Data Bytes = 00F907 (hex)
(a) Read command and outputs. The 3 data bytes are zoomed in for better clarity.
Zoom-in
4th Byte
5th Byte
Configuration Byte (4th) and Repeated Configuration Byte (5th)
(b) Read command and outputs. The last two data bytes are zoomed in for better clarity.
FIGURE 1-16:
Read Command and Data on I2C bus. Note the RDY bit in 4th byte is “0”. This means
the conversion data just read is the latest conversion data. The RDY bit becomes “1” in the 5th byte
(repeated byte). This means the device is now in the process of new conversion and the new result is not
ready yet.
© 2008 Microchip Technology Inc.
DS51778A-page 21
MCP3423 Evaluation Board User’s Guide
1.4
EXPERIMENT FOR CH2
Repeat the instructions from Section 1.3.2 “Creating Script Files” to
Section 1.3.4 “Reading the Conversion Data using the PICkit Serial Analyzer” for
the input channel 2.
DS51778A-page 22
© 2008 Microchip Technology Inc.
MCP3423 EVALUATION BOARD
USER’S GUIDE
Appendix A. Schematic and Layouts
A.1
INTRODUCTION
This appendix contains the following schematics and layouts for the MCP3424 Evaluation Board:
•
•
•
•
•
Board – Schematic
Board – Top Layer
Board – Top Metal Layer
Board – Bottom Layer
Board – Bottom Metal Layer
© 2008 Microchip Technology Inc.
DS51778A-page 23
MCP3423 Evaluation Board User’s Guide
A.2
BOARD – SCHEMATIC
DS51778A-page 24
© 2008 Microchip Technology Inc.
Schematic and Layouts
A.3
BOARD – TOP LAYER
© 2008 Microchip Technology Inc.
DS51778A-page 25
MCP3423 Evaluation Board User’s Guide
A.4
BOARD – TOP METAL LAYER
DS51778A-page 26
© 2008 Microchip Technology Inc.
Schematic and Layouts
A.5
BOARD – BOTTOM LAYER
© 2008 Microchip Technology Inc.
DS51778A-page 27
MCP3423 Evaluation Board User’s Guide
A.6
BOARD – BOTTOM METAL LAYER
DS51778A-page 28
© 2008 Microchip Technology Inc.
MCP3423 EVALUATION BOARD
USER’S GUIDE
Appendix B. Bill of Materials (BOM)
TABLE B-1:
Qty
BILL OF MATERIALS (BOM)
Reference
Description
Manufacturer
Part Number
1
C1
CAP .1UF 25V CERAMIC X7R 0805
Panasonic® - ECG
ECJ-2VB1E104K
1
C2
CAP CERAMIC 10UF 6.3V X5R 0805
Panasonic - ECG
ECJ-2FB0J106K
1
D1
LED RED ORANGE CLEAR 0805 SMD LITE-ON INC
LTST-C170EKT
2
R1,R3
RES 4.99K OHM 1/8W 1% 0805 SMD
Panasonic - ECG
ERJ-6ENF4991V
1
R5
RES 470 OHM 1/8W 5% 0805 SMD
Panasonic - ECG
ERJ-6GEYJ471V
1
J1
CONN HEADER 6POS .100 R/A TIN
Molex®/ Waldom®
Electronics
22-05-2061
1
JP1
CONN HEADER 2POS .100 VERT TIN
Molex/Waldom
Electronics
22-03-2021
2
JP2,JP3
CONN HEADER 3POS .100" STR TIN
Molex/Waldom
Electronics
90120-0123
1
PCB
RoHS Compliant Bare PCB, MCP3423
Evaluation Board for PICkit Serial
Microchip Technology
Inc.
104-00230
3
Shunts for
JP1, JP2,
JP3
100" Shorting Block with Handle
JAMECO Value-Pro
2012JH-R
2
R2,R4
DO NOT POPULATE
—
—
1
U1
2 Channel 18 Bit Data Sigma ADC
Microchip Technology
Inc.
MCP3423-E/ST
14
VDD1,
TEST POINT PC COMPACT SMT
CH1+, CH1-,
CH2+, CH2-,
A0, A1, SCL,
SDA, GND
Keystone Electronics®
5016
Note 1:
The components listed in this Bill of Materials are representative of the PCB assembly. The released BOM
used in manufacturing uses all RoHS-compliant components.
© 2008 Microchip Technology Inc.
DS51778A-page 29
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01/02/08
DS51778A-page 30
© 2008 Microchip Technology Inc.