MCP4728
Evaluation Board
User’s Guide
© 2009 Microchip Technology Inc.
DS51837A
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DS51837A-page ii
© 2009 Microchip Technology Inc.
MCP4728 EVALUATION BOARD
USER’S GUIDE
Table of Contents
Preface ........................................................................................................................... 1
Introduction............................................................................................................ 1
Document Layout .................................................................................................. 1
Conventions Used in this Guide ............................................................................ 2
Recommended Reading........................................................................................ 2
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 MCP4728 Evaluation Board .............................................. 5
1.3 Getting Started with PICkit Serial Analyzer .................................................... 7
Appendix A. Schematic and Layouts
A.1 Introduction .................................................................................................. 35
A.2 Board – Schematic ....................................................................................... 36
A.3 Board – Top Silk, Top Pads and Top Copper .............................................. 37
A.4 Board – Top Copper and Pads .................................................................... 38
A.5 Board – Top Pads and Silk .......................................................................... 39
A.6 Board – Bottom Copper Layer ..................................................................... 40
Appendix B. Bill Of Materials (BOM)
Appendix C. MCP4728 Read/Write Commands
C.1 Introduction .................................................................................................. 43
Worldwide Sales and Service .................................................................................... 46
© 2009 Microchip Technology Inc.
DS51837A-page iii
MCP4728 Evaluation Board User’s Guide
NOTES:
DS51837A-page iv
© 2009 Microchip Technology Inc.
MCP4728 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
MCP4728 Evaluation Board. Items discussed in this chapter include:
•
•
•
•
•
Document Layout
Conventions Used in this Guide
Recommended Reading
The Microchip Web Site
Customer Support
DOCUMENT LAYOUT
This document describes how to use the MCP4728 Evaluation Board with PICkitTM
Serial Analyzer. The manual layout is as follows:
• Chapter 1. “Quick Start Instructions” – this chapter provides an overview of the
MCP4728 Evaluation Board and instructions on how to use the MCP4728
Evaluation Board with the PICkitTM Serial Analyzer.
• Appendix A. “Schematic and Layouts” – shows the schematic and layout
diagrams for the MCP4728 Evaluation Board.
• Appendix B. “Bill Of Materials (BOM)” – lists the parts used to build the
MCP4728 Evaluation Board.
• Appendix C. “MCP4728 Read/Write Commands” – shows the read/write commands for the MCP4728 Evaluation Board.
© 2009 Microchip Technology Inc.
DS51837A-page 1
MCP4728 Evaluation Board User’s Guide
CONVENTIONS USED IN THIS GUIDE
This manual uses the following documentation conventions:
DOCUMENTATION CONVENTIONS
Description
Represents
Examples
Code (Courier font):
Plain characters
Sample code
Filenames and paths
#define START
c:\autoexec.bat
Angle brackets: < >
Variables
<label>, <exp>
Square brackets [ ]
Optional arguments
MPASMWIN [main.asm]
Curly brackets and pipe
character: { | }
Choice of mutually exclusive arguments; An OR selection
errorlevel {0|1}
Lowercase characters in Type of data
quotes
“filename”
Ellipses...
Used to imply (but not show) additional text that is not relevant to the
example
list
[“list_option...,
“list_option”]
0xnnn
A hexadecimal number where n is a
hexadecimal digit
0xFFFF, 0x007A
Italic characters
A variable argument; it can be either a char isascii (char,
type of data (in lowercase characters) ch);
or a specific example (in uppercase
characters).
Interface (Arial font):
Underlined, italic text
with right arrow
A menu selection from the menu bar
File > Save
Bold characters
A window or dialog button to click
OK, Cancel
Characters in angle
brackets < >
A key on the keyboard
<Tab>, <Ctrl-C>
Referenced books
MPLAB® IDE User’s Guide
Documents (Arial font):
Italic characters
RECOMMENDED READING
This user's guide describes how to use MCP4728 Evaluation Board. Other useful
documents are listed below. The following Microchip documents are 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.
MCP4728 Data Sheet, “12-Bit, Quad Digital-to-Analog Converter with EEPROM
Memory” DS22187
This data sheet provides detailed information regarding for the MCP4728
Digital-to-Analog Converter.
DS51837A-page 2
© 2009 Microchip Technology Inc.
Preface
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 Guide, 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
Development Systems Information Line
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 (June 2009)
• Initial Release of this Document.
© 2009 Microchip Technology Inc.
DS51837A-page 3
MCP4728 Evaluation Board User’s Guide
NOTES:
DS51837A-page 4
© 2009 Microchip Technology Inc.
MCP4728 EVALUATION BOARD
USER’S GUIDE
Chapter 1. Quick Start Instructions
1.1
INTRODUCTION
The following sections provide an overview of the MCP4728 Evaluation Board and
instructions on how to program the DAC register and the EEPROM of the MCP4728
using the PICkitTM Serial Analyzer. The following sections cover the topics:
• Description of the MCP4728 Evaluation Board
• How to use the MCP4728 Evaluation Board with the PICkit Serial Analyzer
1.2
DESCRIPTION OF THE MCP4728 EVALUATION BOARD
The purpose of the MCP4728 Evaluation Board is to provide an easy way of evaluating
the MCP4728’s performance and functionality with a minimum of work.
The MCP4728 Evaluation Board contains a MCP4728 (which is a 4-channel, 12-bit
Digital-to-Analog Converter), an interface connector for the PICkit Serial Analyzer, and
I2C test point terminals.The user can evaluate this board by using the PICkit Serial
Analyzer or by providing the I2C serial communication signals through the I2C test
terminals.
Using the MCP4728 Evaluation Board, the user can evaluate the functionality of the
MCP4728 device, such as: (a) Writing and reading the DAC registers and EEPROM of
each channel, (b) Selecting the reference voltage, (c) Measuring the DAC output
voltage, (d) Checking the LDAC pin feature, etc.
The MCP4728 Evaluation Board is designed to work friendly with the PICkit Serial
Analyzer (DV164122). The PICkit Serial Analyzer (P/N: DV164122) is used for writing
and reading the DAC configuration and register data. The PICkit Serial Analyzer
consists of hardware and PC GUI. It is highly recommended that the users order this
MCP4728 Evaluation Board and the PICkit Serial Analyzer at same time.
• The MCP4728 supports standard mode (100 kHz), fast mode (400 kHz), and high
speed mode (3.4 MHz) of the I2C serial communications. This evaluation board
has 5 kΩ for the I2C pull-up resistors and supports up to the fast mode. If the user
needs to evaluate the device with high speed mode (3.4 MHz), please replace the
R1 and R2 with lower values (less than 1 kΩ).
Note:
The MCP4728 Evaluation Board can be used without the PICkit Serial
Analyzer as long as the VDD, SCL, and SDA are provided through the J1
connector. This board does not include MCU.
The MCP4728 Evaluation Board has test points for SDL, SDA, and DAC outputs. By
connecting an oscilloscope to these I2C test points, the user can examine the data
communications through the I2C™ bus line and observe the resulting analog output (at
VOUT terminals) using a multimeter. Refer to Appendix A. “Schematic and Layouts”.
© 2009 Microchip Technology Inc.
DS51837A-page 5
MCP4728 Evaluation Board User’s Guide
FIGURE 1-1:
TABLE 1-1:
Test
Terminals
Front View of the MCP4728 Evaluation Board.
TEST TERMINALS ON THE MCP4728 EVALUATION BOARD
Description
VOUT A
VOUT B
VOUT C
VOUT D
SCL
DAC channel A output
DAC channel B output
DAC channel C output
DAC channel D output
This terminal is connected to the I2C SCL pin of the MCP4728.
(See Note 1).
SDA
This terminal is connected to the I2C SDA pin of the MCP4728.
(See Note 1).
This terminal is used to monitor the RDY/BUSY pin of the MCP4728 device.
RDY/BUSY
Access terminal to the LDAC pin of the MCP4728.
LDAC
S1
Switch to change the logic input to the LDAC input pin. It provides logic “low”
when pressed.
JP1
Jumper to select the VDD source to the MCP4728 Evaluation Board. If it is
connected, the VDD from the J1 connector is connected. If disconnected, it
selects the VDD source from VDD1 terminal.
JP2
Jumper to connect the LDAC pin to VSS. (You can disconnect this jumper
when S1 is used.)
VDD1
VDD monitoring or connection pin.
If the VDD is provided from J1 connector (PICkit Serial Analyzer), then this
test point monitors the VDD voltage. You can also connect a new VDD to this
test terminal.
GND
Connected to common ground plane of the PC Board.
Note 1: This terminal is used to monitor the SCL or SDA signals. You can also provide the
SCL or SDA signals through these pins.
DS51837A-page 6
© 2009 Microchip Technology Inc.
Quick Start Instructions
1.3
GETTING STARTED WITH PICKIT SERIAL ANALYZER
Figure 1-1 shows the MCP4728 Evaluation Board, and Figure 1-2 shows the
connection of the MCP4728 Evaluation Board and PICkit Serial Analyzer.
The following steps describe how to use them together:
1. Connect the MCP4728 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 terminals (optional).
3. Connect a multimeter to one of the DAC’s output test terminal.
4. 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.
I 2C
•
device code of MCP4728: ‘1100’
• A2, A1, A0 Address Bits: Pre-programmed to‘000’.
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.
6. Use the PICkit Serial Analyzer PC GUI to send I2C write and read commands.
© 2009 Microchip Technology Inc.
DS51837A-page 7
MCP4728 Evaluation Board User’s Guide
.
Personal
Computer
USB Cable
Connected between the
PICkit Serial Analyzer
and Personal Computer
PICkit Serial Analyzer
DAC Output
(Channel B)
MCP4728 Evaluation Board
FIGURE 1-2:
DS51837A-page 8
MCP4728 Evaluation Board with the PICkit Serial Analyzer.
© 2009 Microchip Technology Inc.
Quick Start Instructions
1.3.1
PICkit Serial Analyzer PC Software Setup for the MCP4728
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. Click the
Next button and follow the instructions.
FIGURE 1-3:
PICkit Serial Analyzer Configuration Wizard Welcome Window.
4. Select the Communication Mode type: I2C Master, and click the Next button.
FIGURE 1-4:
© 2009 Microchip Technology Inc.
Step 1 - Communication Mode Selection.
DS51837A-page 9
MCP4728 Evaluation Board User’s Guide
5. Select 100 kHz or 400 kHz. Either one will be fine. Click the Next button.
FIGURE 1-5:
Note:
Step 2 - I2C Communication Speed Selection.
The MCP4728 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.
6. Select No on Enable Pull-ups and click the Next button.
Note:
The MCP4728 Evaluation Board has its own pull-up resistors.
FIGURE 1-6:
DS51837A-page 10
Step 3 - Device Pull-Ups Window.
© 2009 Microchip Technology Inc.
Quick Start Instructions
7. Select the VDD voltage of the MCP4728 Evaluation Board and 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 below,
the MCP4728 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 MCP4728 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.
FIGURE 1-7:
© 2009 Microchip Technology Inc.
Step 4 - Voltage Source Selection Window.
DS51837A-page 11
MCP4728 Evaluation Board User’s Guide
8. Click the OK button. You have made all of the PICkit Serial Analyzer
Configuration Setups. You are now ready to read/write MCP4728 registers and
EEPROM.
FIGURE 1-8:
DS51837A-page 12
Configuration Wizard - Finishing Step.
© 2009 Microchip Technology Inc.
Quick Start Instructions
1.3.2
Creating Script Files:
A script file that is running on the PICkit Serial PC GUI is needed for the
communications between the PICkit Serial Analyzer and the MCP4728 Evaluation
Board. The following steps show how to create script files and how to use them. Refer
to the PICkit Serial Analyzer User’s Guide (DS51647) for creating the Script file.
• Select Communication -----> Script ---> Script Builder
FIGURE 1-9:
© 2009 Microchip Technology Inc.
Creating a Script File with Script Builder.
DS51837A-page 13
MCP4728 Evaluation Board User’s Guide
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 clicking with the
right mouse button.
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. An option box will appear 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 the next examples.
Note:
1.3.2.2
The following examples need knowledge on the MCP4728 Registers and
Command protocols. Please refer to the Appendix C. “MCP4728
Read/Write Commands” and the MCP4728 Data Sheet for more details.
EXAMPLE 1: SELECTING VOLTAGE REFERENCE OF EACH DAC
CHANNEL
You can select the voltage reference of each channel individually. The choices are:
external (VDD) or internal reference voltage (VREF = 2.048V). Figure 1-10 shows an
example of writing a script file on the PICkit Serial PC GUI.
1.
2.
3.
To change value:
• Click this box and
type a new value
To delete or Insert box:
• Select 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.
FIGURE 1-10:
Creating a new Script file to select VREF of each DAC channel. In this example,
external VREF (VREF =VDD) is selected for all DAC channels.
DS51837A-page 14
© 2009 Microchip Technology Inc.
Quick Start Instructions
• Modify the parameters in the Script Detail column as below:
Script Detail
I2CSTART
*
I2CWRTBYT *
02
--------> This means there are two bytes to send.
C0
--------> Address byte = 1100-0000 (See Note).
80
--------> 1’st byte (000-0000) selecting external VREF.
I2CSTOP
*
Note:
1.3.2.3
All 6 parameters above must be listed in order. The parameters with * are
not modifiable. The MCP4728 device on the evaluation board has I2C
address bits (A2, A1, A0) = (0,0,0).
SAVE THE SCRIPT FILE AND PROGRAMMING THE MCP4728 DAC
REGISTERS
1. Type in a script file name (i.e., MCP4728_W_VrfSel) in the space below the
Script Name menu.
2. Click Save Script button.
3. Click Execute Script button.
Note:
At this point, the PICkit Serial Analyzer transmits the I2C Write Command
to the MCP4728 device. The saved file name will appear in the Users I2C
Scripts column, and can be re-used any time by selecting the file name.
4. You can also see the SCL and SDA waveforms using an Oscilloscope.
Note:
© 2009 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 including
the I2C address of the device, and try again until the “Busy” LED turns OFF
immediately after sending the I2C command.
DS51837A-page 15
MCP4728 Evaluation Board User’s Guide
1.3.2.4
EXAMPLE 2: SELECTING GAIN OF EACH DAC CHANNEL
You can select the Gain of each channel individually. Figure 1-11 shows an example of
writing a new script file on the PICkit Serial PC GUI for selecting the gain option. In this
example, Gain of 1 is selected.
.
1.
2.
3.
To change value:
• Click this box and
type a new value
To delete or Insert box:
• Select 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.
FIGURE 1-11:
Writing Script file to select VREF of each DAC channel. In this example, Gain of 1 is
selected for all DAC channels.
• Parameters in the Script Detail column:
Script Detail
I2CSTART
*
I2CWRTBYT
*
02
-----> This means there are two bytes to send.
C0
-----> Address byte = 1100-0000 (See Note).
C0
---- > Selecting the gain of each channel (0: Gain of 1, 1: gain of 2)
I2CSTOP
*
Note:
DS51837A-page 16
All parameters above must be listed in order. The parameter above with *
are not modifiable. The MCP4728 device on the evaluation board has I2C
address bits (A2, A1, A0) = (0,0,0).
© 2009 Microchip Technology Inc.
Quick Start Instructions
1.3.2.5
SAVE THE SCRIPT FILE AND PROGRAMMING THE MCP4728 DAC
REGISTERS
1. Type in any script name (i.e., MCP4728_W_GainSl) in the space below the
Script Name menu.
2. Click Save Script button.
3. Click Execute Script button.
Note:
At this point, the PICkit Serial transmits the I2C Write Command to the
MCP4728 device. The saved file name will appear in Users I2C Scripts
column, and can be re-used any time by selecting the file name.
4. You can also see the SCL and SDA waveforms using the Oscilloscope.
Note:
© 2009 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 including
the I2C address of the device, and try again until the “Busy” LED turns OFF
immediately after sending the I2C command.
DS51837A-page 17
MCP4728 Evaluation Board User’s Guide
1.3.2.6
Note:
EXAMPLE 3: WRITING DAC REGISTERS WITH A FAST WRITE
COMMAND
Please refer to the MCP4728 data sheet for the Fast Write Command
structure before excising this example.
Figure 1-12 shows an example of writing a script file on PICkit Serial PC GUI for a Fast
Write Command. This command writes to the DAC input registers and power-down
selection bits. The data are sent sequentially from channel A to the channel D.
EEPROM is not affected. This device updates the DAC output registers (VOUT) when
LDAC pin is low.
1.
2.
3.
To change value:
• Click this box and
type a new value
To delete or Insert box:
• Select 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.
FIGURE 1-12:
Writing Script File to Write Each DAC Register with a Fast Write Command Using the
PICkit Serial Analyzer.
DS51837A-page 18
© 2009 Microchip Technology Inc.
Quick Start Instructions
• Parameters in the Script Detail column:
Script Detail
I2CSTART
I2CWRTBYT
09
C0
0F
FF
07
FF
03
FF
01
FF
I2CSTOP
Note:
1.3.2.7
*
*
-------> This means there are nine bytes to send.
-------> Address byte = 1100-0000 (See Note).
-------> 1st byte of DAC A Register (Channel A) = 0000-1111
-------> 2nd byte of DAC A Register (Channel A) = 1111-1111
-------> 1st byte of DAC B Register (Channel B) = 0000-0111
-------> 2nd byte of DAC B Register (Channel B) =1111-1111
-------> 1st byte of DAC C Register (Channel C) = 0000-0011
-------> 2nd byte of DAC C Register (Channel C) = 1111-1111
-------> 1st byte of DAC D Register (Channel D) = 0000 -0001
-------> 2nd byte of DAC D Register (Channel D) = 1111-1111
*
All parameters above must be listed in order. The parameter above with *
are not modifiable. The MCP4728 device on the evaluation board has I2C
address bits (A2, A1, A0) = (0,0,0).
SAVE THE SCRIPT FILE AND PROGRAMMING THE MCP4728 DAC
REGISTERS
1. Type in any script name (i.e., MCP4728_W_Fast) in the space below the Script
Name menu.
2. Click Save Script button.
3. Click Execute Script button.
Note:
At this point, the PICkit Serial transmits the I2C Write Command to the
MCP4728 device. The saved file name will appear in Users I2C Scripts
column, and can be re-used any time by selecting the file name.
4. 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 including
the I2C address of the device, and try again until the “Busy” LED turns OFF
immediately after sending the I2C command.
5. Read the VOUT voltage at the VOUT test pads:
In order to update the DAC output register, the LDAC pin must be “Low”.
• Press “S1” button in the MCP4728 Evaluation Board.
The device will update the VOUT as soon as the LDAC pin switch S1 is pressed.
You can now measure the DAC output voltages (VOUT A, VOUT B, VOUT C, VOUT D)
using a voltmeter. When Examples 1, 2, and 3 are executed sequentially, all channels
use an internal reference. Figure 1-13 shows the expectation of each DAC channel outputs.
© 2009 Microchip Technology Inc.
DS51837A-page 19
MCP4728 Evaluation Board User’s Guide
Start
1st Byte
1
1
0
0
0
0
0
Address Byte
0 A
0
0
0
0
D11
Fast Mode Write Command
Stop
3rd Byte
2nd Byte
D10
D9
D8
A
D7
D6
D5
D4
D3
D2
D1
D0
A
DAC A
Next DAC Channels
The following example shows when the device receives the Fast Write command
with the following data:
DAC Input Data of Channel A = 001111-11111111
DAC Input Data of Channel B = 000111-11111111
DAC Input Data of Channel C = 000011-11111111
DAC Input Data of Channel D = 000001-11111111
( V REF × D n )
V OUT = ------------------------------- G x
4096
(A) Channel A Output:
In Script file, Dn for Channel A = 0FFF (hex) = 4095 (decimal)
V OUT A
( V DD × 4095 )
4096 – 1
1 -⎞ =
= ---------------------------------- = V DD ⎛ ---------------------⎞ = V DD ⎛ 1 – ----------V DD – LSB
⎝ 4096 ⎠
⎝
4096
4096⎠
(B) Channel B Output:
In Script file, Dn for Channel B = 07FF (hex) = 2047 (decimal)
V OUT B
V DD
( V DD × 2047 )
V DD
2048 – 1
2
= ---------------------------------- = V DD ⎛⎝ ---------------------⎞⎠ = ----------- ⎛⎝ 1 – ------------⎞⎠ = ---------- – LSB
4096
2
4096
4096
2
(C) Channel C Output:
In Script file, Dn for Channel C = 03FF (hex) = 1023 (decimal)
V DD
V DD × 1023
V DD
1024 – 1
4
- – LSB
V OUT C = -------------------------------- = V DD ⎛⎝ ---------------------⎞⎠ = ----------- ⎛⎝ 1 – ------------⎞⎠ = ---------4096
4
4096
4096
4
(D) Channel D Output:
In Script file, Dn for Channel D = 01FF (hex) = 511 (decimal)
V DD
V DD × 511
V DD
512 – 1
8
V OUT D = ----------------------------- = V DD ⎛ ------------------⎞ = ----------- ⎛ 1 – ------------⎞ = ---------- – LSB
⎝
⎠
4096
8 ⎝
4096
4096⎠
8
FIGURE 1-13:
VOUT for Example 3: Fast Write Command for Various VOUT. VREF = VDD and
Gain = 1 for All Channels.
DS51837A-page 20
© 2009 Microchip Technology Inc.
Quick Start Instructions
1.3.2.8
EXAMPLE 4: MULTI-WRITE COMMAND FOR DAC INPUT REGISTERS
This command writes to the multiple DAC input registers, one register at a time. The
writing channel register is defined by the DAC selection bits (DAC1, DAC0). EEPROM
is not affected by this command.
Figure 1-14 shows an example of creating the PICkit Script file. In this example, the the
PICkit Serial Analyzer sends a write command to the DAC input registers A and B.
1.
2.
3.
To change value:
• Click this box and
type a new value
To delete or Insert box:
• Select 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.
FIGURE 1-14:
Writing Script file to Write Channel A for FFFh and Channel B for 800h Using a
Multi-write Command.
© 2009 Microchip Technology Inc.
DS51837A-page 21
MCP4728 Evaluation Board User’s Guide
• Parameters in the Script Detail column:
Script Detail
I2CSTART
I2CWRTBYT
07
C0
40
0F
FF
02
08
00
I2CSTOP
Note:
1.3.2.9
*
*
-------> This means there are seven bytes to send.
-------> Address byte = 1100-0000 (See Note).
-------> Command Type and Selecting Channel A DAC
-------> Configuration register bits and data nibble
-------> Data byte
-------> Selecting Channel B DAC
-------> Configuration register bits and data nibble
-------> Data byte
*
All parameters above must be listed in order. The parameters above with *
are not modifiable. The MCP4728 device on the evaluation board has I2C
address bits (A2, A1, A0) = (0,0,0).
SAVE THE SCRIPT FILE AND PROGRAMMING THE MCP4728 DAC
REGISTERS
1. Type in any script name (i.e., MCP4728_W_MDAC) in the space below the
Script Name menu.
2. Click Save Script button.
3. Click Execute Script button.
Note:
At this point, the PICkit Serial transmits the I2C Write Command to the
MCP4728 device. The saved file name will appear in Users I2C Scripts
column, and can be re-used any time by selecting the file name.
4. 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 including
the I2C address of the device, and try again until the “Busy” LED turns OFF
immediately after sending the I2C command.
5. Read the VOUT voltage at the VOUT test pins:
Since the UDAC bit is set to “0” in the command, the device will update the VOUT A and
VOUT B as soon as the command is executed regardless of the condition of the LDAC
pin switch S1.
DS51837A-page 22
© 2009 Microchip Technology Inc.
Quick Start Instructions
( V REF × D n )
V OUT = ------------------------------- G x
4096
(A) Channel A Output:
In Script file, Dn for Channel A = 0FFF (hex) = 4095 (decimal)
V OUT A
( V DD × 4095 )
4096 – 1
1 -⎞ = V – LSB
= ---------------------------------- = V DD ⎛⎝ ---------------------⎞⎠ = V DD ⎛⎝ 1 – ----------DD
4096
4096
4096⎠
(B) Channel B Output:
In Script file, Dn for Channel B = 0800 (hex) = 2048 (decimal)
V OUT B
( V DD × 2048 )
V DD
= ---------------------------------- = ---------4096
2
(C) Channel C Output:
No change. The device maintains its output with previous settings.
(D) Channel D Output:
No change. The device maintains its output with previous settings.
Where:
VREF
Dn
LSB
=
=
=
=
VDD if external VREF is selected
2.048V if internal VREF is selected.
Input code
VREF/4096
Note that Dn and Gain (Gx) must be selected with the following conditions:
( V REF × D n )
V OUT = ------------------------------- G x
4096
Figure 1-15:
and Gain = 1.
≤ V DD
VOUT for Example 4: Multi-Write Command for Channels A and B with VREF = VDD
© 2009 Microchip Technology Inc.
DS51837A-page 23
MCP4728 Evaluation Board User’s Guide
1.3.2.10
EXAMPLE 5: SINGLE WRITE COMMAND FOR DAC INPUT REGISTER
AND EEPROM
This command writes to a single DAC input register and its EEPROM. Both input
register and EEPROM are written at the acknowledge pulse of the input data byte. The
EEPROM program activity can be monitored through the RDY/BSY bit and pin. See the
MCP4728 data sheet for details.
Figure 1-16 shows an example of writing a script file. In this example, the PICkit Serial
Analyzer sends a single write command to the MCP4728 for the DAC A (Channel A)
input register.
.
1.
2.
3.
To change value:
• Click this box and
type a new value
To delete or Insert box:
• Select 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.
FIGURE 1-16:
Writing Script File to Write the Channel A Register and its EEPROM with FFFh Using
a Single Write Command. The Channel A output is updated immediately with the ACK Pulse. This example
uses UDAC Bit, instead of using LDAC pin, to update the DAC output.
• Parameters in the Script Detail column:
Script Detail
I2CSTART
I2CWRTBYT
04
C0
58
0F
FF
I2CSTOP
Note:
DS51837A-page 24
*
*
-------> This means there are four bytes to send.
-------> Address byte = 1100-0000 (See Note).
-------> Command Type and selection of Channel A.
-------> Configuration register bits and data nibble for Channel A.
-------> Data byte for Channel A (register and its EEPROM).
*
All parameters above must be listed in order. The parameter above with *
are not modifiable. The MCP4728 device on the evaluation board has I2C
address bits (A2, A1, A0) = (0,0,0).
© 2009 Microchip Technology Inc.
Quick Start Instructions
1.3.2.11
SAVE THE SCRIPT FILE AND PROGRAMMING THE MCP4728 DAC
REGISTERS
1. Type in any script name (i.e., MCP4728_W_SingEE) in the space below the
Script Name menu.
2. Click Save Script button.
3. Click Execute Script button.
Note:
At this point, the PICkit Serial transmits the I2C Write Command to the
MCP4728 device. The saved file name will appear in Users I2C Scripts
column, and can be re-used any time by selecting the file name.
4. 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 including
the I2C address of the device, and try again until the “Busy” LED turns OFF
immediately after sending the I2C command.
5. Read the VOUT voltage at the VOUT test pins:
Since the UDAC bit is set to “0” in the command, the device will update the channel A
(VOUT A) output as soon as the command is executed regardless of the condition of the
LDAC pin switch S1.
© 2009 Microchip Technology Inc.
DS51837A-page 25
MCP4728 Evaluation Board User’s Guide
( V REF × D n )
V OUT = ------------------------------- G x
4096
(A) Channel A Output:
In Script file, Dn for Channel A = 0FFF (hex) = 4095 (decimal)
V OUT A
( V DD × 4095 )
4096 – 1
1 -⎞ =
= ---------------------------------- = V DD ⎛ ---------------------⎞ = V DD ⎛ 1 – ----------V DD – LSB
⎝ 4096 ⎠
⎝
4096
4096⎠
(B) Channel B Output:
No change. Keep its output with previous settings.
(C) Channel C Output:
No change. Keep its output with previous settings.
(D) Channel D Output:
No change. Keep its output with previous settings.
Where:
VREF
Dn
LSB
=
=
=
=
VDD if external VREF is selected
2.048V if internal VREF is selected.
Input code
VREF/4096
Note that Dn and Gain (Gx) must be selected with the following conditions:
( V REF × D n )
V OUT = ------------------------------- G x
4096
FIGURE 1-17:
DS51837A-page 26
≤ V DD
VOUT for Example 5: Single Write Command for Channel A: VREF = VDD and Gain = 1.
© 2009 Microchip Technology Inc.
Quick Start Instructions
1.3.2.12
EXAMPLE 6: SEQUENTIAL WRITE FOR DAC INPUT REGISTERS AND
EEPROM
This command writes to the DAC input registers and EEPROM sequentially from a start
channel to the channel D. The input register is written at the ACK pulse of the input data
byte of each register. However, the EEPROM are written altogether at the same time
sequentially at the end of the last byte. The EEPROM writing activity can be monitored
through the RDY/BSY bit and pin. See the MCP4728 data sheet for details.
Figure 1-18 shows an example of writing a script file on PICkit Serial PC GUI for this
command.
.
1.
2.
3.
To change value:
• Click this box and
type a new value
To delete or Insert box:
• Select 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.
FIGURE 1-18:
Writing Script file to write the Channel B to Channel D. This command writes to both
the input registers and EEPROM: (a) Channel B Settings: VREF = VDD and Gain = 1. (b) Channel C
Settings: VREF = Internal (2.048V), Gain = 1. (c) Channel D Settings: VREF = Internal (2.048V), Gain = 2.
The DAC outputs are updated immediately with the ACK pulse. This example uses the UDAC bit to update
the DAC outputs.
© 2009 Microchip Technology Inc.
DS51837A-page 27
MCP4728 Evaluation Board User’s Guide
• Parameters in the Script Detail column:
Script Detail
I2CSTART
I2CWRTBYT
08
C0
52
0F
FF
8F
FF
90
FF
I2CSTOP
Note:
1.3.2.13
*
*
-------> This means there are eight bytes to send.
-------> Address byte = 1100-0000 (See Note).
-------> Command Type and Ch. B is a starting channel
-------> Configuration register bits and data nibble for Ch. B
-------> Data byte for Ch. B
-------> Configuration register bits and data nibble for Ch. C
-------> Data byte for Ch. C
-------> Configuration register bits and data nibble for Ch. D
-------> Data byte for Ch. D
*
All parameters above must be listed in order. The parameter above with *
are not modifiable. The MCP4728 device on the evaluation board has I2C
address bits (A2, A1, A0) = (0,0,0).
SAVE THE SCRIPT FILE AND PROGRAMMING THE MCP4728 DAC
REGISTERS
1. Type in any script name (i.e., MCP4728_W_SeqB) in the space below the Script
Name menu.
2. Click Save Script button.
3. Click Execute Script button.
Note:
At this point, the PICkit Serial transmits the I2C Write Command to the
MCP4728 device. The saved file name will appear in Users I2C Scripts
column, and can be re-used any time by selecting the file name.
4. 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 including
the I2C address of the device, and try again until the “Busy” LED turns OFF
immediately after sending the I2C command.
5. Read the VOUT voltage at the VOUT test terminals:
Since the UDAC bit is set to “0” in the command, the device will update the VOUT B, C,
and D outputs as soon as the command is executed regardless of the condition of the
LDAC pin switch S1.
DS51837A-page 28
© 2009 Microchip Technology Inc.
Quick Start Instructions
( V REF × D n )
V OUT = ------------------------------- G x
4096
(A) DAC A Output:
No change. Keep its output with previous settings.
(B) DAC B Output:
In Script file, VREF = VDD, Gain (GX) = 1, Dn for Channel B = 0FFF (hex) = 4095 (decimal)
( V DD × 4095 )
4096 – 1
1 -⎞ = V – LSB
= ---------------------------------- G x = V DD ⎛ ---------------------⎞ = V DD ⎛ 1 – ----------DD
⎝ 4096 ⎠
⎝
4096
4096⎠
V OUT B
(C) DAC C Output:
In Script file, VREF = Internal, Gain (GX) = 1, Dn for Channel C = 0FFF (hex) = 4095 (decimal)
V OUT C
( V REF × 4095 )
4096 – 1
1 -⎞ = V
= ------------------------------------ G x = V REF ⎛ ---------------------⎞ = V REF ⎛ 1 – ----------REF – LSB
⎝
⎝ 4096 ⎠
4096
4096⎠
= 2.0475
where VREF = internal = 2.048V, LSB =0.5 mV
(D) DAC D Output:
In Script file, VREF = Internal, Gain = 2, Dn for Channel D = 00FF (hex) = 255 (decimal)
V OUT D
=
V REF × 255
255-⎞
---------------------------- G x = V REF ⎛ ----------2 = V REF ( 0.06226 ) ( 2 ) = 0.255V
⎝ 4096⎠
4096
where VREF = internal = 2.048V
Where:
VREF
Dn
LSB
=
=
=
=
VDD if external VREF is selected
2.048V if internal VREF is selected.
Input code
VREF/4096
Note that Dn and Gain (Gx) must be selected with the following conditions:
( V REF × D n )
V OUT = ------------------------------- G x
4096
FIGURE 1-19:
≤ V DD
VOUT for Example 6: VOUT after Sequential Write Command.
© 2009 Microchip Technology Inc.
DS51837A-page 29
MCP4728 Evaluation Board User’s Guide
1.3.2.14
EXAMPLE 7: TESTING EEPROM FEATURES
The device will upload the EEPROM data to both input and output DAC registers (a)
during power-up sequence or (b) when it receives the General Call Reset command.
One of these conditions makes the analog outputs available immediately with their
current EEPROM settings. Note that the Power-Down bit must be cleared for the
output.
• Testing Procedure:
a. Write to the EEPROM with one of the examples shown earlier (i.e.,
Section 1.3.2.12 “Example 6: Sequential Write for DAC Input Registers and
EEPROM”).
b. Measure and record the analog voltage of each channel (VOUT) using a
multimeter.
c. Turn-off the VDD of the device. If you are using the VDD from the PICkit Serial
Analyzer, disconnect JP1 connect.
d. Turn-back on the VDD again and measure the analog voltage (VOUT) of each
channel again. Confirm the VOUT is the same as in Step (b).
1.3.2.15
EXAMPLE 8: READING DAC REGISTERS AND EEPROM
This example shows how to read back the DAC input registers and EEPROM data.
Figure 1-20 shows the PICkit Serial script file to read all DAC input registers and
EEPROM data. Once this file is executed, the PC GUI will show you the contents of the
registers and EEPROM.
.
18h = 24 (decimal):
Requesting 24 bytes.
Read Command
Reading Data
FIGURE 1-20:
Reading the DAC Registers and its EEPROM with a Read Command. See
Figure 1-21 for Details in Reading Data.
DS51837A-page 30
© 2009 Microchip Technology Inc.
Quick Start Instructions
Note:
In Figure 1-20, the script file called “MCP4728_Read” was created, saved
and executed.
.
DAC A Register
DAC C Register
DAC B Register
DAC A EEPROM
DAC C EEPROM
DAC D Register
Ch. A Register: C0-0F-FF:
Ch. A EEPROM: C8-0F-FF:
Ch. B Register: D0-0F-FF:
Ch. B EEPROM: D8-0F-FF:
Ch. C Register: E0-8F-FF:
Ch. C EEPROM: E8-0F-FF:
Ch. D Register: F0-90-FF:
Ch. D EEPROM: F8-90-FF:
DAC B EEPROM
DAC C EEPROM
VREF = VDD, GA = x1, Data = FFFh
VREF = VDD, GA = x1, Data = FFFh
VREF = VDD, GA = x1, Data = FFFh
VREF = VDD, GA = x1, Data = FFFh
VREF = VDD, GA = x1, Data = FFFh
VREF = VDD, GA = x1, Data = FFFh
VREF = VDD, GA = x2, Data = 0FFh
VREF = VDD, GA = x2, Data = 0FFh
FIGURE 1-21:
The contents of the Registers and EEPROM. The order of the
contents: Channel A Register and EEPROM, and Channel B Register and EEPROM,
and so on sequentially. See the Read Command and Device Output details in
MCP4728 Data Sheet.
© 2009 Microchip Technology Inc.
DS51837A-page 31
MCP4728 Evaluation Board User’s Guide
1.3.2.16
EXAMPLE 9: WRITE POWER-DOWN SELECTION BITS IN DAC INPUT
REGISTER
This command writes power-down bits to the DAC input registers.
Figure 1-22 shows an example of writing a new script file for Power-Down mode.
.
1.
2.
3.
To change value:
• Click this box and
type a new value
To delete or Insert box:
• Select 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.
FIGURE 1-22:
Writing Script file to write the power-down bits. The channel outputs are updated
immediately with the ACK pulse. This command does not require UDAC bit or LDAC pin change.
• Parameters in the Script Detail column:
Script Detail
I2CSTART
I2CWRTBYT
03
C0
AF
FF
I2CSTOP
Note:
DS51837A-page 32
*
*
-------> This means there are three bytes to send.
-------> Address byte = 1100-0000 (See Note).
-------> Command Type and Power-Down bits for Chs. A and B.
-------> Power-Down bits for Channels C and D.
*
All parameters above must be listed in order. The parameter above with *
are not modifiable. The MCP4728 device on the evaluation board has I2C
address bits (A2, A1, A0) = (0,0,0).
© 2009 Microchip Technology Inc.
Quick Start Instructions
1.3.2.17
SAVE THE SCRIPT FILE AND PROGRAMMING THE MCP4728 DAC
REGISTERS
1. Type in any script name (i.e., MCP4728_W_PDown) in the space below the
Script Name menu.
2. Click Save Script button.
3. Click Execute Script button.
Note:
At this point, the PICkit Serial transmits the I2C Write Command to the
MCP4728 device. The saved file name will appear in Users I2C Scripts
column, and can be re-used any time by selecting the file name.
4. 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 re-check the parameter values
including the order of parameters under the “Script Detail” column including
the I2C address of the device, and try again until the “Busy” LED turns OFF
immediately after sending the I2C command.
5. Read the VOUT voltage at the VOUT test pins:
Once this command is executed, all analog voltage outputs (VOUT) will be “zero”, and
the analog output pins (VOUT) are internally connected with about 500 kΩ.
© 2009 Microchip Technology Inc.
DS51837A-page 33
MCP4728 Evaluation Board User’s Guide
NOTES:
DS51837A-page 34
© 2009 Microchip Technology Inc.
MCP4728 EVALUATION BOARD
USER’S GUIDE
Appendix A. Schematic and Layouts
A.1
INTRODUCTION
This appendix contains the following schematics and layouts for the MCP4728
Evaluation Board:
•
•
•
•
•
Board – Schematic
Board – Top Silk, Top Pads, and Top Copper Layer
Board – Top Copper and Pads Layer
Board – Top Pads and Silk Layer
Board – Bottom Copper Layer
© 2009 Microchip Technology Inc.
DS51837A-page 35
MCP4728 Evaluation Board User’s Guide
A.2
BOARD – SCHEMATIC
DS51837A-page 36
© 2009 Microchip Technology Inc.
Schematic and Layouts
A.3
BOARD – TOP SILK, TOP PADS AND TOP COPPER
© 2009 Microchip Technology Inc.
DS51837A-page 37
MCP4728 Evaluation Board User’s Guide
A.4
BOARD – TOP COPPER AND PADS
DS51837A-page 38
© 2009 Microchip Technology Inc.
Schematic and Layouts
A.5
BOARD – TOP PADS AND SILK
© 2009 Microchip Technology Inc.
DS51837A-page 39
MCP4728 Evaluation Board User’s Guide
A.6
BOARD – BOTTOM COPPER LAYER
DS51837A-page 40
© 2009 Microchip Technology Inc.
MCP4728 EVALUATION BOARD
USER’S GUIDE
Appendix B. Bill Of Materials (BOM)
TABLE B-1:
Qty
BILL OF MATERIALS
Reference
Description
Manufacturer
Part Number
4
C1, C3, C4, C5
CAP 1000PF 50V CERAMIC X7R
0603
Panasonic® - ECG
ECJ-1VB1H102K
1
C2
CAP CERAMIC 10UF 6.3V X5R
0603
Panasonic - ECG
ECJ-1VB0J106M
1
D1
LED RED CLEAR 0805 SMD
Lite-On Inc
LTST-C170CKT
CONN HEADER 6POS .100 R/A
TIN
Molex®/Waldom®
Electron-
22-05-2061
ics Corp
1
J1
2
JP1, JP2
CONN HEADER 2POS .100 VERT
TIN
Molex/Waldom Electronics
Corp
22-03-2021
1
PCB
RoHS Compliant Bare PCB,
MCP4728 Evaluation board
Microchip Technology Inc.
104-00229
4
R1, R2, R4, R5
RES 4.99K OHM 1/10W 1% 0603
SMD
Panasonic - ECG
ERJ-3EKF4991V
1
R3
RES 470 OHM 1/8W 5% 0805 SMD Panasonic - ECG
ERJ-6GEYJ471V
®
13
RDY/~BSY,
SCL, SDA,
VDDA, VOUTA,
VOUTB,
VOUTC,
VOUTD, LDAC,
GND
TEST POINT PC COMPACT SMT
Keystone Electronics
1
S1
SWITCH LIGHT TOUCH 160GF
SMD
Panasonic - ECG
EVQ-PPBA25
1
U1
Microchip Technology Inc.
MCP4728-E/UN
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.
© 2009 Microchip Technology Inc.
DS51837A-page 41
MCP4728 Evaluation Board User’s Guide
NOTES:
DS51837A-page 42
© 2009 Microchip Technology Inc.
MCP4728 EVALUATION BOARD
USER’S GUIDE
Appendix C. MCP4728 Read/Write Commands
C.1
INTRODUCTION
Table summarizes the write command types and their functions. The write command
is defined by using three write command type bits (C2, C1, C0) and two write function
bits (W1, W0). Writing and reading the I2C address bits are not demonstrated with the
PICKit Serial Analyzer. Please see the MCP4728 data sheet for more details on the
commands.
TABLE C-1:
WRITE COMMAND TYPES
Command Field
C2
C1
C0
Write
Function
W1
Command Name
Function
W0
Fast Mode Write
0
0
X
Not Used
Fast Write for DAC This command writes to the DAC input registers sequentially
Input Registers
with limited configuration bits. The data is sent sequentially
from channels A to D. The input register is written at the
acknowledge clock pulse of the channel’s last input data byte.
EEPROM is not affected. (Note 1)
Write DAC Input Register and EEPROM
0
1
0
0
0
Multi-Write for DAC This command writes to multiple DAC input registers, one DAC
Input Registers
input register at a time. The writing channel register is defined
by the DAC selection bits (DAC1, DAC0). EEPROM is not
affected. (Note 2)
1
0
Sequential Write for This command writes to both the DAC input registers and
DAC Input RegisEEPROM sequentially. The sequential writing is carried out
ters and EEPROM from a starting channel to channel D. The starting channel is
defined by the DAC selection bits (DAC1 and DAC0).
The input register is written at the acknowledge clock pulse of
the last input data byte of each register. However, the
EEPROM data is written altogether at the same time sequentially at the end of the last byte. (Note 2),(Note 3)
1
1
This command writes to a single selected DAC input register
Single Write for
DAC Input Register and its EEPROM. Both the input register and EEPROM are
and EEPROM
written at the acknowledge clock pulse of the last input data
byte. The writing channel is defined by the DAC selection bits
(DAC1 and DAC0). (Note 2),(Note 3)
Write I2C Address Bits (A2, A1, A0)
0
1
Note 1:
2:
3:
4:
1
Not Used
Write I2C Address
Bits
This command writes new I2C address bits (A2, A1, A0) to the
DAC input register and EEPROM.
The analog output is updated when LDAC pin is (or changes to) “Low”. UDAC bit is not used for this
command.
The DAC output is updated when LDAC pin or UDAC bit is “Low”.
The device starts writing to the EEPROM on the acknowledge clock pulse of the last channel. The device
does not execute any command until RDY/BSY bit comes back to “High”.
The input and output registers are updated at the acknowledge clock pulse of the last byte. The update
does not require LDAC pin or UDAC bit conditions. EEPROM is not affected.
© 2009 Microchip Technology Inc.
DS51837A-page 43
MCP4728 Evaluation Board User’s Guide
TABLE C-1:
WRITE COMMAND TYPES (CONTINUED)
Command Field
C2
C1
C0
Write
Function
W1
Command Name
Function
W0
Write VREF, Gain, and Power-Down Select Bits (Note 4)
1
0
0
Not Used
1
1
0
Not Used
1
0
1
Not Used
Note 1:
2:
3:
4:
Write Reference This command writes reference (VREF) selection bits of each
channel.
(VREF) selection
bits to Input Registers
Write Gain selection bit to Input
Registers
This command writes Gain selection bits of each channel.
Write Power-Down This command writes Power-Down bits of each channel.
bits to Input Registers
The analog output is updated when LDAC pin is (or changes to) “Low”. UDAC bit is not used for this
command.
The DAC output is updated when LDAC pin or UDAC bit is “Low”.
The device starts writing to the EEPROM on the acknowledge clock pulse of the last channel. The device
does not execute any command until RDY/BSY bit comes back to “High”.
The input and output registers are updated at the acknowledge clock pulse of the last byte. The update
does not require LDAC pin or UDAC bit conditions. EEPROM is not affected.
DS51837A-page 44
© 2009 Microchip Technology Inc.
MCP4728 Read/Write Commands
NOTES:
© 2009 Microchip Technology Inc.
DS51837A-page 45
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03/26/09
DS51837A-page 46
© 2009 Microchip Technology Inc.