Microchip Technology MCP3901, PIC18F65J90 User Manual

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MCP3901 and PIC18F65J90

Energy Meter Reference Design

User’s Guide

Page 2

Note the following details of the code protection feature on Microchip devices:

• Microchip products meet the specification contained in their particular Microchip Data Sheet.

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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 t he lik e is provided only for your convenience and may be su perseded by upda t es . It is y our responsibility to ensure that your application meets with your specifications. MICROCHIP MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND WHETHER EXPRESS OR IMPLIED, WRITTEN OR ORAL, STATUTORY OR OTHERWISE, RELATED TO THE INFORMATION, INCLUDING BUT NOT LIMITED TO ITS CONDITION, QUALITY, PERFORMANCE, MERCHANTABILITY OR FITNESS FOR PURPOSE. Microchip disclaims all liability arising from this information and its use. Use of Microchip devices in life supp ort and/or safety ap plications is entir ely at the buyer’s risk, and the buyer agrees to defend, indemnify and hold harmless M icrochip from any and all dama ges, claims, suits, or expenses re sulting from such use. No licens es are conveyed, implicitly or otherwise, under any Microchip intellectual property rights.

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EELOQ, KEELOQ logo, MPLAB, PIC, PICmicro, PICSTART,

PIC

logo, rfPIC and UNI/O are registered trademarks of Microchip Technology Incorporated in the U.S.A. and other countries.

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All other trademarks mentioned herein are property of their respective companies.

Printed on recycled paper.

ISBN: 978-1-61341-960-1

Microchip received ISO/TS-16949:2009 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 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.

MCUs and dsPIC® DSCs, KEELOQ

code hopping

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MCP3901 AND PIC18F65J90

ENERGY METER

REFERENCE DESIGN

Preface ...........................................................................................................................7

Introduction............................................................................................................7

Document Layout .................................................................................................. 8

Conventions Used in this Guide............................................................................ 9

Recommended Reading.............................................................. .. ......................10

The Microchip Web Site...................................................................................... 10

Customer Support.................... .................................... .................. .....................10

Document Revision History................................................................................. 10

Chapter 1. Product Overview

1.1 Introduction ...................................................................................................11

1.2 What the MCP3901 and PIC18F65J90 Energy Meter

Reference Design Kit Includes ............................................................... 12

1.3 Getting Sta rted .... .................................................................................. ....... 12

Chapter 2. Hardware

2.1 Overview ............. ......................................................................................... 13

2.2 Input and Analog Front End .........................................................................16

Chapter 3. Calculation Engine and Register Description

3.1 Calculati on E n g in e Si g nal Flow Summary ................................................... 17

3.2 Register L is t ................................................................................................. 18

3.3 MODE .......................................................................................................... . 19

3.4 STATUS .......... .. ........................................................................................... 20

3.5 CAL_CONT R O L ........................................................................................... 20

3.6 LINE_CYC ................. .. ................................................................................ 21

3.7 LINE_CYC _ C N T ............. ... ..................................................... .. .. ................ 2 1

3.8 RAW2_I_RMS ..............................................................................................21

3.9 RAW_I_RM S .................... .......................................... .................................. 22

3.10 I_RMS ............... ......................................................................................... 22

3.11 RAW2_V _ R M S ......................................................................................... 22

3.12 RAW_V_ R M S .......................... ........................................................ ......... 22

3.13 V_RMS ....... ... .. ........................................................................................... 22

3.14 LINE_F R E Q UE N CY ............................................... .................................... 23

3.15 RAW_PO WER_ACT ......................................... ........................................ 23

3.16 POWER_ A CT ..................................... .......................................... .............. 23

3.17 POWER_APP ............................................................................................23

3.18 RAW_PO WER_REACT .......... ................ ................................................... 24

3.19 POWER_ R EA CT ...... .. .. ............................. .......................................... ....... 24

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MCP3901 and PIC18F65J90 Energy Meter Reference De sign

3.20 PERIOD .... ....................................................... ........................................... 24

3.21 ENERG Y _ AC T ............. .. ............................ ................................................ 24

3.22 ENERGY_APP ..........................................................................................25

3.23 I_ABS_MAX ...............................................................................................25

3.24 V_ABS _ M A X ............. ... .............................................................................. 2 5

3.25 ENERG Y _ RE A C T ...................................................................................... 25

3.26 PHASE_COMPENSATION ........................................................................ 25

3.27 OFFSE T _ I_ R M S .. .. .................................................................................. . 26

3.28 OFFS ET _ V _RMS . .. ..................................................... .. ... ......................... 2 6

3.29 GAIN_I_RMS ............................................................................................. 26

3.30 GAIN_V _ R MS ............................................................................................ 26

3.31 OFFSE T _ P O WE R _ A CT .................... ...................................................... 26

3.32 GAIN_P O WER_ACT ........ .. ........................................................................ 27

3.33 OFFSE T _ P O WE R _ RE ACT .............. ........................................................ 27

3.34 GAIN_P O WER_REACT ... .................................................................... ...... 27

3.35 GAIN_E N E RGY_ACT ................................................................................ 27

3.36 GAIN_ENERGY_APP ................................................................................ 27

3.37 GAIN_E N E RGY_REACT . .. .. ...................................................................... 27

3.38 CF_PU LSE_WIDTH ............. ...................................................................... 28

3.39 GAIN_D E N R_ENERGY_A C T ......... ................ ........................................... 28

3.40 GAIN_N U MR_ENERGY_ A CT ............................................ ....................... 28

3.41 MODE1 _ D EF ............................................................. .............................. 28

3.42 CAL_ST A T US ........... ... .......................... .. .. ................................................ 28

3.43 MAXIMUM CURRENT ............................................................................. 29

3.44 CALIB R AT ION_VOLTAG E ....... .. ..................................................... .. ... ... 29

3.45 CALIBRATION_CURRENT ......................................................................29

3.46 CALIB R AT ION_FREQUE N CY . ................................................................. 29

3.47 METER _ C ON S T A N T ......................................... ....................................... 2 9

3.48 CALIB R A T I O N _ L INE _ C Y CLE ................................................. ... .. ............ 30

3.49 GAIN_D E N R_ENERGY_R EA C T ............ .. ... ............................................. 30

3.50 GAIN_N U MR_ENERGY_ R E ACT ............. ................................................ 30

3.51 PHASE_COMPENSATION_90 ................................................................. 30

3.52 CREEP_THRSHOLD_MINUTE ................................................................. 30

3.53 CREEP_THRSHOLD_SECOND ................................................................30

Chapter 4. Meter Protocol and Timings

4.1 Protocol ..................................................... .. ... ............................................. 31

Appendix A. Schematic and Layouts

A.1 Introduction .................................................................................................. 33

A.2 Schematics and PCB Layout ........................ ......................... .. .. ..................33

A.3 Board – ADC Schematic ............................................................................. 34

A.4 Board – MCU S c he matic ........... .. ............. .. ... ............................................. 35

A.5 Board – LCD and USB Schematic .............. .. ............................... ................36

A.6 Board – Top Silk and Pads ........................ .. ..................... .......................... 37

A.7 Board – Top Copper .................................................................................... 38

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A.8 Board – Bottom Copper ...............................................................................39

A.9 Board – Bottom Silk and Pads ..................... .. .. .. ............................. .. ...........40

A.10 Board – To p 3 D ............................................................. .. .. ............. ... .. ....... 41

A.11 Board – Bo tt om 3D ...... ............. ... .. ............. .. .. ........................... .. .. ............ 42

Appendix B. Bill of Materials (BOM)

Worldwide Sales and Service ....................................................................................46

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MCP3901 and PIC18F65J90 Energy Meter Reference De sign

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MCP3901 AND PIC18F65J90

ENERGY METER

REFERENCE DESIGN

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 p age 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 Select the Help menu, and then Topics to open a list of available online help files.

IDE online help.

INTRODUCTION

This chapter contains general information that will be useful to know before using the MCP3901 and PIC18F65J90 Energy Meter Reference Design User’s Guide. Items discussed in this chapter include:

• Document Layout

• Conventions Used in this Guide

• Recommended Reading

• The Microchip Web Site

• Customer Support

• Document Revision History

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MCP3901 and PIC18F65J90 Energy Meter Reference De sign

DOCUMENT LAYOUT

This document describes how to use the MCP3901 and PIC18F65J90 Energy Meter Reference Design as a development tool to emulate and debug firmware on a target board. The manual layout is as follows:

• Chapter 1. “Product Overview” – Important information on using the MCP3901

and PIC18F65J90 Energy Meter Reference Design including a Getting Started section that describes wiring the line and load connections.

• Chapter 2. “Hardwa re ” – Includes details on the function blocks of the meter

including the analog front end design, phase lock loop circuitry, and power supply design.

• Chapter 3. “Calculation Engine and Register Description” – This section

describes the digital signal flow for all power output quantities such as RMS current, RMS voltage, active power, and apparent power. This section also includes the calibration register’s detail.

• Chapter 4. “Meter Protocol and Timings”– This chapter describes the protocol

used for accessing the registers, including commands that are used to interface to the meter.

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

diagrams.

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

MCP3901 and PIC18F65J90 Energy Meter Reference Design.

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CONVENTIONS USED IN THIS GUIDE

This manual uses the following docum entat io n conven tion s:

DOCUMENTATION CONVENTIONS

Description Represents Examples

Arial font:

Italic chara c ters Referenced books MPLAB

Initial caps A window the Output window

Quotes A field name in a window or

Underlined, italic text with right angle bracket

Bold characters A dialog button Click OK

N‘Rnnnn A number in verilog format,

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

Courier New font:

Plain Courier New Sample source code #define START

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

Square brackets [ ] Optional arguments mcc18 [options] file

Curly brackets and pipe character: { | }

Ellipses... Replaces r epeated text var_name [,

Preface

IDE User’s Guide

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

A dialog the Settings dialog A menu selection select Enable Programmer

“Save project before build”

dialog A menu path File>Save

A tab Click the Power tab

4‘b0010, 2‘hF1 where N is the tota l number of digits, R is th e radi x and n is a digit.

Filenames autoexec.bat File paths c:\mcc18\h Keywords _asm, _endasm, static Command-line options -Opa+, -Opa- Bit values 0, 1 Constants 0xFF, ‘A’

any valid filename

[options]

Choice of mut ually exclus ive arguments; an OR selection

Represents code supplied by user

errorlevel {0|1}

var_name...]

void main (void)

{ ...

}

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MCP3901 and PIC18F65J90 Energy Meter Reference De sign

DOCUMENT REVISION HISTORY

Revision A (January 2012)

• Initial Release of this Document.

Page 11

Chapter 1. Product Overview

1.1 INTRODUCTION

The MCP3901 and PIC18F65J90 Energy Meter Reference Design is a fully functional IEC Class 0.5 compliant single-phase meter. This low-cost design does not use any transformers and requires few external components. The PIC18F65J90 directly drives the LCD, and includes both an isolated USB connection for meter calibration and access to the device power calculations. The system calculates active energy, active power, RMS current, RMS voltage, reactive energy, reactive power, apparent power and other typical power quantities.

The Microchip Energy Meter 1-Phase Software is used to calibrate and monitor the system, and can be used to create custom calibration setups. For some accuracy requirements, only a single point calibration may be needed. The energy meter software offers an automated step-by-step calibration process that can be used to quickly calibrate energy meters.

MCP3901 AND PIC18F65J90

ENERGY METER

REFERENCE DESIGN

FIGURE 1-1: MCP3901 and PIC18F65J90 Single-Phase Energy Meter.

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MCP3901 and PIC18F65J90 Energy Meter Reference De sign

1.2 WHAT THE MCP3901 AND PIC18F65J90 ENERGY METER REFERENCE DESIGN KIT INCLUDES

This MCP3901 and PIC18F65J90 Energy Meter Reference Design kit includes:

• MCP3901 and PIC18F65J90 Energy Meter Reference Design User’s Guide

• Important Information Sheet

1.3 GETTING STARTED

To describe how to use the MCP3901 and PIC18F65J90 Energy Meter Reference Design, the following example is given using a two-wire 1-phase, 220 V AC line voltage and connections using energy meter calibrator equipment, or other programmable load source. The meter design uses a 5A load for calibration current, and a maximum current (I

To test a calibrated meter, the following connections apply for a two-wire connection.

1.3.1 Step 1: Wiring Connections

Figure 1-2 identifies the line and load connections of the MCP3901 and PIC18F65J90 Energy Meter Reference Design.

MAX

) of 60A.

Line

Neutral

MAIN

Line

Neutral

LOAD

FIGURE 1-2: Example Connections using a 2-Wire System.

1.3.2 Step 2: Turn On Line/Load Power to the Meter (Power the Meter)

The meter will turn on when the line connection has 220V connected. The LCD display will show the total energy accumulated.

Page 13

2.1 OVERVIEW

Figures 2-1 and 2-2 show the MCP3901 and PIC18F65J90 and Energy Meter

Reference Design:

MCP3901 AND PIC18F65J90

ENERGY METER

REFERENCE DESIGN

Chapter 2. Hardware

LCD1

D9D8

SW3

SW1

C40

SW2

DANGER

HIGH VOLTAGE

MCP3901 / PIC18F65J90 SHUNT METER

Legend:

1 = IR for meter communication 7 = Push button Switches 2 = Test points 8 = 9-digit LCD Disp lay with icons for kWh and kVARh 3 = MCP3901 Analog Front End 9 = Pulse Output for Active and Reactive

4 = +9V DC Input (non-isolated) 10 = USB Connection (isolated) 5 = Connections to shunt

current sensing resistor

6 = Connections to Line and Neutral

(isolated)

FIGURE 2-1: Top View – Hardware Components.

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MCP3901 and PIC18F65J90 Energy Meter Reference De sign

C40

R21 R20

R28

R27 R26

C32

C24 C25

R19

R17

R29

C39

R33

C37

R30

R34

DANGER

HIGH VOLTAGE

C41

R14 R12 C2

R15 R11 C1

C38

C30 C27 C21 C22

C10

R31 C23

R24 R25

C19

C17

R18

C16

MOV1

R32

Legend:

12 = Opto-isolators for Pulse outputs 13 = Power supply 14 = Non-volatile memory for calibration constants and energy usage data 15 = PIC18F65J90 16 = Isolation IC 17 = MCP2200 for USB connection

FIGURE 2-2: Bottom View – Hardware Components.

Page 15

Hardware

PIC18F65J90

RA2

RA3 RG1

RG4

RC7/RX RC6/TX

RA5

RC3/SCK

RC4/SDI

RC5/SDO

RA1

SWITCH SWITCH

USB to UART

Converter

MCP2200

Active Power

Mini - USB Connector

(ISOLATED)

SCK

SDO

SDI CS

MCP3901

AFE

SCK

SDO

SDI CS

Reactive Power

FIGURE 2-3: Digital Connections.

25LC256

SPI - EEPROM

Page 16

MCP3901 and PIC18F65J90 Energy Meter Reference De sign

2.2 INPUT AND ANALOG FRONT END

The MCP3901 and PIC18F65J90 and Energy Meter Reference Design comes populated with components designed for 220V line voltage. At the bottom of the main board are the high voltage line and neutral connections. There are four connections that are made from the PCB to the meter casing. They are labeled LINE, NEUTRAL, SHUNT1, and SHUNT2. The shunt sits on the high or line side of a two-wire system and the meter employs a hot or “live” ground. The wires going into the shunt to SHUNT1 and SHUNT2 should be twisted together. The wires going into the LINE and NEUTRAL side of the meter should be twisted together, and also kept away from the SHUNT1 and SHUNT2 wires if possible.

The neutral side of the two-wire system goes into a resistor divider on the voltage channel input. Anti-aliasing low-pass filters will be included on both differential channels. The voltage channel uses two 332 kΩ resistors to achieve a divider ratio of 664:1. For a line voltage of 230 V 490 mV

PEAK

, the channel 1 input signal size will be

RMS

LINE_SHUNT1

Shunt

(external to PCB part of meter case)

LINE_SHUNT2

NEUTRAL

150 FB (Note)

332 kΩ

332 k Ω

1.0 kΩ

10-step optional

resistor

ladder

1.0 kΩ

Note: FB = ferrite beads. Ferrite beads have an impedance of the

specified value at 100 MHz.

CH0+

68 nF

CH0-

68 nF

MCP3901

0Ω

CH1+

68 nF

CH1+

68 nF

FIGURE 2-4: Analog Input Circuitry.

Page 17

MCP3901 AND PIC18F65J90 ENERGY

METER REFERENCE DESIGN

Chapter 3. Calculation Engine and Register Description

3.1 CALCULATION ENGINE SIGNAL FLOW SUMMARY

RMS voltage, RMS current, Active Power, Reactive Power and Apparent Power, and the calibration output pulse are all calculated through the following process described in Figure 3-1. The calibration registers for each calculation are shown as well as the

16/24-bit

ADC

CURRENT

GAIN_ COMPENSATION _90:

16/24-bit DS ADC

ADC

VOLTAGE

output registers.

ΔΣ

ADC

90°

with

Correction

OFFSET_I_RMS:

RMS Current

Reactive Power

FFSET_POWER_REACT:32

Active Power

ASE_COMPENSATION:8

OFFSET_V_RMS:

OFFSET_POWER_ACT:

Apparent Power

NUMR_ENERGY_ACT:16

GAIN_

GAIN_DENR_ENERGY_ACT:

1/METER_CONSTAT

imp/kWh

DENR_ENERGY_REACT:8

GAIN_

imp/kVARh

Digital to Frequency Converter

NUMR_ENERGY_REACT:16

GAIN_

1/METER_CONSTAT

GAIN_POWER_REACT:

kVAR

POWER_REACT:

RMS Voltage

GAIN_ENERGY_REACT:

kVARh

REACT:32

ENERGY_

kVA

POWER_APP:

GAIN_ENERGY_ACT:

kWh

GAIN_V_RMS:

_RMS:16

GAIN_I_RMS:

GAIN_POWER_ACT:

_RMS:16

GAIN_POWER_APP:

POWER_ACT:

GAIN_ENERGY_APP:

kVAh

ACT:32

ENERGY_

APP:32

ENERGY_

FIGURE 3-1: PIC18F65J90 Calculation Engine Signal Flow

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MCP3901 and PIC18F65J90 Energy Meter Reference De sign

3.2 REGISTER LIST

Note: Important! Not all registers and features

are implemented in this version of firmware release.

TABLE 3-1: INTERNAL REGISTER SUMMARY

Name Bits R/W Description

MODE 8 R/W Configuration register for operating mode of the meter STATUS 8 R STATUS register CAL_CONTROL 8 R/W Configuration register for calibration control LINE_CYC 16 R/W 2n number of line cycles to be used during energy accumulation LINE_CYC_CNT 16 R Counter for number of line cycles

RAW2_I_RMS 64 R Raw RAW_I_RMS 16 R Raw RMS value from the current A/D converter in LSBs I_RMS 16 R RMS value of the current, post Calibration RAW2_V_RMS 64 R Raw RAW_V_RMS 16 R Raw RMS value from the voltage A/D converter in LSBs V_RMS 16 R RMS value of the voltage, post Calibration LINE_FREQUENCY 16 R Line Frequency RAW_POWER_ACT 64 R Raw Active Power POWER_ACT 32 R Final Active Power, units in watts (W) POWER_APP 32 R Final Apparent Power, units in volt-am peres (VA) RAW_POWER_REACT 64 R Raw Reactive Power POWER_REACT 32 R Final Reactive Power, units in volt-amperes-reactive (VAR) PERIOD 32 R Period register ENERGY_ACT 32 R Final Active Energy accumulated RAW_ENERGY_ACT 64 R Raw Active Energy accumulated ENERGY_APP 32 R Final Apparent Energy accu mulated RAW_ENERGY_APP 64 R Raw Apparent Energy accumulated I_ABS_MAX 8 R Not implemented V_ABS_MAX 8 R Not implemented ENERGY_REACT 32 R Final Reactive Energy accumulated RAW_ENERGY_REACT 64 R Final Reactive Energy accumulated PHASE_COMPENSATION 8 R/W Phase compensation between voltage and current OFFSET_I_RMS 16 R/W Offset adjustment for RMS current reading OFFSET_V_RMS 16 R/W Offset adjustment for RMS voltage reading GAIN_I_RMS 16 R/W Gain adjustment for RMS current GAIN_V_RMS 16 R/W Gain adjustment for RMS voltage OFFSET_POWER_ACT 32 R/W Act ive Power offset GAIN_POWER_ACT 16 R/W Ac tive Power gain adjust OFFSET_POWER_REACT 32 R/W Offset correction for Reactive Power GAIN_POWER_REACT 16 R/W Reactive Power gain adjust to produce X VAR/LSB GAIN_ENERGY_ACT 16 R/W Not implemented GAIN_ENERGY_APP 16 R/W Not implemented GAIN_ENERGY_REACT 16 R/W Not implemented CF_PULSE_WIDTH 8 R/W Defines CF pulse width from 0 to 255 x 0.8192 ms (0.209s) GAIN_DENR_ENERGY_ACT 8 R/W Active Energy Pulse Output correction factor

RMS value from the current A/D converter in LSBs

RMS value from the voltage A/D converter in LSBs

Page 19

Calculation Engi ne and Register Description

TABLE 3-1: INTERNAL REGISTER SUMMARY (CONTINUED)

Name Bits R/W Description

GAIN_NUMR_ENERGY_ACT 16 R/W Active Energy Pulse Output correction factor MODE1_DEF 16 R/W Power Up Configuration Register CAL_STATUS 16 R/W Calibration Status MAXIMUM CURRENT 16 R/W Maximum current of the meter (I CALIBRATION_VOLTAGE 16 R/W Calibration Voltage of the meter (V CALIBRATION_CURRENT 16 R/W Calibration Current of the meter (I CALIBRATION_FREQUENCY 16 R/W Calibration Frequency of the meter METER_CONSTANT 16 R/W Meter Constant in imp/kWh or imp/kVARh CALIBRATION_LINE_CYCLE 16 R/W Number of line cycles for calibration GAIN_DENR_ENERGY_REACT 8 R/W Reactive Energy Pulse Output correction factor GAIN_NUMR_ENERGY_REACT 16 R/W Reactive Energy Pulse Output correction factor PHASE_COMPENSATION_90 8 R/W Phase delay for Reactive Power CREEP_THRSHOLD_MINUTE 8 R/W No Load threshold time (minutes) CREEP_THRSHOLD_SECOND 8 R/W No Load threshold time (seconds) ENERGY_ACT 32 R/W Active Energy ENERGY_REACT 32 R/W Reactive Energy

MAX

CAL

)

3.3 MODE

The MODE register controls the operation of the energy meter. The bit functions are defined by the table below.

U-0 U-0 U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0

— — — — CF ABSOLUTE PHASE CREEP

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7-4 Unimplemented: Read as ‘0’. bit 3 CF: Active Energy CF Phase Enable bit

1 = Bit = 1 Phase is enabled to be accumulated into the total energy registers or CF pulse output 0 = Bit = 0 Phase is DISABLED and is not accumulated into the total energy registers or CF pulse

output

bit 2 ABSOLUTE Positive Only Energy Accumulation Mode bit

1 = Bit = 1 Positive energy only 0 = Bit = 0 Both negative and positive energy accumulated (negative energy is subtracted)

bit 1 PHASE: Phase bit

1 = Single-Point Phase Correction 0 = Multi-P oint Phase C orrection ( future)

bit 0 CREEP: No-Load Threshold bit

1 = Enabled 0 = Disabled

Page 20

MCP3901 and PIC18F65J90 Energy Meter Reference De sign

3.4 STATUS

The STATUS register contains the operational status of the energy meter. The bit functions are defined in the table below.

U-0 U-0 U-0 U-0 U-0 U-0 R U-0

— — — — — —PH_S—

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7-2 Unimplemented: Read as ‘0’ bit 1 PH_S: Phase Sign bit

1 = CT may be in backward (if enabled) 0 = Operation normal

bit 0 Unimplemented: Read as ‘0’

3.5 CAL_CONTROL

This is the Calibration mode control register. Bit 0 enables the Calibration mode. In this mode, the power meter operates as normal, but no updates are made to the voltage, current, power or energy registers as long as bit 1 is low. When bit 1 is set high, the registers are updated for LINE_CYC line cycles (only power and energy registers are updated). After this time, bit 1 is set low by the PIC18F65J90 and the update of the registers will stop. This allows the calibration software to set bit 0, clear the registers, set bit 1 and start reading the desired registers, as well as the CAL_CONTROL register, to check the status of bit 1. When bit 1 goes low, the LINE_CYC line cycles have passed and the registers are final. Note that bit 0 takes effect immediately, and bit 1 will take effect on the very next line cycle. When bit 1 goes low, all registers will be ready to read.

U-0 U-0 U-0 U-0 U-0 U-0 R/W-0 R/W-0

— — — — — Reserved CAL_UPDATE CAL_MODE

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7-3 Unimplemented: Read as ‘0’ bit 2 Reserved:

Page 21

Calculation Engi ne and Register Description

bit 1 CAL_UPDATE: Calibration Update bit

Power and energy registers upda ted for LINE _CYC lin e cy cl es when cle are d. Bit mu st be set for registers to begin updating, which starts on the next line cycle after bit is set.

1 = When the CAL_MODE bit is set, set the CAL_U PDA TE bit to enable update of power and energy

registers starting on next line cycle. Bit = 1 Single Point Phase Correction.

0 = When the CAL_MODE bit is set and the CAL_UPDATE bit has been set, the CAL_UPDATE bit

will be cleared after LINE_CYC line cycles. At that point, all registers will be updated and no further updates will be done until the CAL_UPDATE bit is set again, or the CAL_MODE bit is cleared.

bit 0 CAL_MODE: Calibration Mode bit

This bit enables Calibration mode.

1 = Calibration mode enabled 0 = Calibration mode disabled

Note 1: This register is used in Multi-Point and Single-Point Calibration modes only.

3.6 LINE_CYC

Name Bits Cof

LINE_CYC 16 R/W

Number of line cycles as a power of two. A setting of 0 indicates 20 or one line cycle. A setting of 1 is two line cycles (2 of eight which is 256 line cycles. When written, this register will not take effect until the previous number of line cycles has been acquired.

3.7 LINE_CYC_CNT

Name Bits Cof

LINE_CYC_CNT 16 R

This register counts from 0 and finishes at 2 LINE_CYC represents the value in the LINE_CYC register.

3.8 RAW2_I_RMS

Name Bits Cof

RAW2_I_RMS 64 R

This register is the square of the raw RMS value from the current A/D converter in LSBs. By definition, this register will always contain a positive value, including the situation where power is negative from a backwards CT or otherwise. This register is overwritten every LINE_CYC line cycle and is written only once, if calibration is enabled.

), a setting of 2 is four lines cycles (22), up to a setting

(LINE_CYC - 1)

. Then it restarts at 0, where

Page 22

MCP3901 and PIC18F65J90 Energy Meter Reference De sign

3.9 RAW_I_RMS

Name Bits Cof

RAW_I_RMS 16 R

This register is the raw RMS value from the current A/D converter in LSBs (square root of the top 32-bits of RAW2_I_RMS + OFFSET_I_RMS). By definition, this register will always contain a positive value (even if the CT is in backwards). This register is overwritten every LINE_CYC line cycle and is written only once, if calibration is enabled.

3.10 I_RMS

Name Bits Cof

I_RMS 16 R

This register is the RMS value of phase A current in X A/LSB, as determined by the value in the GAIN _I_RMS regist er . When display ing the RMS curr ent, multiply the (decimal) value in these registers by X to get the display value in amperes. This register is overwritten every LINE_CYC line cycle (written only once if calibration is enabled).

3.11 RAW2_V_RMS

Name Bits Cof

RAW2_V_RMS 64 R

This register is the square of the raw RMS value from the voltage A/D converter in LSBs. By definition, it will always contain a positive value. This register is overwritten every LINE_CYC line cycle (written only once if calibration is enabled).

3.12 RAW_V_RMS

Name Bits Cof

RAW_V_RMS 16 R

This is the raw RMS value from the voltage A/D converter in LSBs (square root of the top 32-bits of RAW2_V_RMS + OFFSET_V_RMS). By definition, this register will always contain a positive value. The register is overwritten every LINE_CYC line cycle (written only once if calibration is enabled).

3.13 V_RMS

Name Bits Cof

V_RMS 16 R

This register is the RMS value of the voltage, in X 0.01 V/LSB, as determined by the value in the GAIN_V_RMS register. When displaying the RMS voltage, assume a calibrated meter exists and multiply the (decimal) value in these registers by X to get the display value in volts. This register is overwritten every LINE_CYC line cycle (written only once if calibration is enabled).

Page 23

Calculation Engi ne and Register Description

3.14 LINE_FREQUENCY

Name Bits Cof

LINE_FREQUENCY 16 R

This register holds the measured line frequency using the zero crossing technique.

3.15 RAW_POWER_ACT

Name Bits Cof

RAW_POWER_ACT 64 R

This register is the raw active power, as it represents the sum of current A/D value times voltage A/D value results over LINE_CYC line cycles (each line cycle has 128 results). Each current times voltage multiplication results in a 32-bit word. There are up to 256 line cycles with each line cycle being 128 results, and each result being 32-bit. Thus, 48 bits are needed. This is the register to be read during calibration for calculating the offset and gain values associated with active power, OFFSET_POWER_ACT and GAIN_POWER_ACT. This register is overwritten every line cycle, however if calibration is enabled, the updates will stop once the LINE_CYC line cycles have elapsed.

3.16 POWER_ACT

Name Bits Cof

POWER_ACT 32 R

This register is the value for active power. The goal of the calibration is to get this register value to equal X W/LSB. This is done with the OFFSET_POWER_ACT and GAIN_POWER_ACT registers. When displaying the power, multiply the (decimal) value in this register by X to get the display value in watts. This register is overwritten every LINE_CYC line cycle (written only once if calibration is enabled).

3.17 POWER_APP

Name Bits Cof

POWER_APP 32 R

This is the value of the apparent power. The goal of the calibration is to get this value to equal X VA/LSB. This is done with the GAIN_POWER_APP registers. When displaying the power for phase A, multiply the (decimal) value in this register by X to get the display value in watts. This register is overwritten every LINE_CYC line cycle (written only once if calibration is enabled).

Page 24

MCP3901 and PIC18F65J90 Energy Meter Reference De sign

3.18 RAW_POWER_REACT

Name Bits Cof

RAW_POWER_REACT 64 R

This is the raw reactive power. This register is read during the calibration for calculating the gain values associated with the reactive power and GAIN_POWER_REACT. This register is overwritten every LINE_CYC line cycle (written only once if calibration is enabled). This register is accumulated on a line-cycle basis.

3.19 POWER_REACT

Name Bits Cof

POWER_REACT 32 R

This is the value for reactive power. The goal is to get this value to equal X VAR/LSB. This is done with the GAIN_POWER_REACT register. When displaying the power, multiply the (decimal) value in this register by X to get the display value in watts. This register is overwritten every LINE_CYC line cycle (written only once if calibration is enabled).

3.20 PERIOD

Name Bits Cof

PERIOD 32 R

This 32-bit register represents the total number of clock ticks that elapsed over the most recent LINE_CYC line cycle. Each LSB represents 1.6 µs with a 4 MHz clock on the microcontroller. This register is overwritten every LINE_CYC line cycle (written only once if calibration is enabled).

3.21 ENERGY_ACT

Name Bits Cof ENERGY_ACT 32 R RAW_ENERGY_ACT 64 R

The design updates the Energy register using the CF Pulse blink output count. In this method, the Energy registers increments every pulse by a value equal to 1/(METER_CONSTANT).

ENERGY_ACT = ENERGY_ACT + (1/METER_CONSTANT) The gain calibration registers GAIN_NUMR_ENERGY_ACT and

GAIN_DENR_ENERGY_ACT operate the same for this method also.

Page 25

Calculation Engi ne and Register Description

3.22 ENERGY_APP

Name Bits Cof ENERGY_APP 32 R RAW_ENERGY_APP 64 R

These two registers represent the total apparent energy accumulated so far.

3.23 I_ABS_MAX

Name Bits Cof

I_ABS_MAX 8 R

NOT IMPLEMENTED IN THIS FIRMWARE/SOFTWARE RELEASE.

3.24 V_ABS_MAX

Name Bits Cof

V_ABS_MAX 8 R/W

NOT IMPLEMENTED IN THIS FIRMWARE/SOFTWARE RELEASE.

3.25 ENERGY_REACT

Name Bits Cof ENERGY_REACT 32 R RAW_ENERGY_REACT 64 R

The design updates the reactive energy register using the CF Pulse blink output. In this method, the Energy registers increment every pulse by a value equal to 1/(METER_CONSTANT).

ENERGY_REACT = ENERGY_REACT + (1/METER_CONSTANT) The gain calibration registers GAIN_NUMR_ENERGY_ACT and

GAIN_DENR_ENERGY_ACT operate the same for this method also.

3.26 PHASE_COMPENSATION

Name Bits Cof

PHASE_COMPENSATION 8 R/W

Phase delay, signed 8-bit value, provides the phase compensation by sampling time/2.

Page 26

MCP3901 and PIC18F65J90 Energy Meter Reference De sign

3.27 OFFSET_I_RMS

Name Bits Cof

OFFSET_I_RMS 16 R/W

Square of the offset for RMS current reading, signed 16-bit value. Note that this value should be similar to the ADC’s noise squared. At a gain of 1, the noise will be about 1 LSB, 2 LSBs at a gain of 2, 6 LSBs at a gain of 8, 11 LSBs at a gain of 16, and 22 LSBs at a gain of 32. There may be other sources of noise. Using the square of the offset allows for higher accuracy. The value will be added before the square root is taken when calculating the final RMS value.

3.28 OFFSET_V_RMS

Name Bits Cof

OFFSET_V_RMS 16 R/W

Square of offset for RMS voltage reading, signed 8-bit value. Note that this value should be similar to the ADC’s noise squared. For the voltage channel, the noise will be about 1 LSB. There may be other sources of noise. Using the square of the offset allows for higher accuracy. The value will be added before the square root is taken when calculating the final RMS value.

3.29 GAIN_I_RMS

Name Bits Cof

GAIN_I_RMS 16 R/W

Current gain to produce X A/LSB. The value is always less than one (for example, 32,767 = 0.9999695).

3.30 GAIN_V_RMS

Name Bits Cof

GAIN_V_RMS 16 R/W

Voltage gain to produce 0.1 V/LSB in the V_RMS register. The value is always less than one (for example, 32,767 = 0.9999695).

3.31 OFFSET_POWER_ACT

Name Bits Cof

OFFSET_POWER_ACT 32 R/W

Active power offset (this is a straight offset, not the square, as with voltage and current). A much larger value is needed because the power is a running sum. This is a 32-bit signed value.

Page 27

Calculation Engi ne and Register Description

3.32 GAIN_POWER_ACT

Name Bits Cof

GAIN_POWER_ACT 16 R/W

Active power gain to produce X W/LSB. The value is always less than one (for example, 32,767 = 0.9999695).

3.33 OFFSET_POWER_REACT

Name Bits Cof

OFFSET_POWER_REACT 32 R/W

Reactive power offset (this is a straight offset, not the square, as with voltage and current). A much larger value is needed because the power is a running sum. This is a 32-bit signed value.

3.34 GAIN_POWER_REACT

Name Bits Cof

GAIN_POWER_REACT 16 R/W

Reactive power gain to produce X W/LSB. The value is always less than one (for example, 32,767 = 0.9999695).

3.35 GAIN_ENERGY_ACT

Name Bits Cof

GAIN_ENERGY_ACT 16 R/W

Active energy gain to produce X Wh/LSB. The value is always less than one (for example, 32,767 = 0.9999695).

3.36 GAIN_ENERGY_APP

Name Bits Cof

GAIN_ENERGY_APP 16 R/W

Apparent energy gain to produce X VAh/LSB. The value is always less than one (for example, 32,767 = 0.9999695).

3.37 GAIN_ENERGY_REACT

Name Bits Cof

GAIN_ENERGY_REACT 16 R/W

Reactive energy gain to produce X VARh/LSB. The value is always less than one (for example, 32,767 = 0.9999695).

Page 28

MCP3901 and PIC18F65J90 Energy Meter Reference De sign

3.38 CF_PULSE_WIDTH

Name Bits Cof

CF_PULSE_WIDTH 8 R/W

Defines the CF pulse width from 0 to 255. Length of width is valued * 8 * (1/LINE_FREQUENCY)/128) ms. A maximum of 0.266 seconds for 60 Hz and

0.319 seconds for 50 Hz. If the value is 0, no CF pulse is produced.

3.39 GAIN_DENR_ENERGY_ACT

Name Bits Cof

GAIN_DENR_ENERGY_ACT 8 R/W

8-bit signed value. Represents the number of shifts for active power energy register ENERGY_ACT before GAIN_DENR_ENERGY_ACT is applied.

3.40 GAIN_NUMR_ENERGY_ACT

Name Bits Cof

GAIN_NUMR_ENERGY_ACT 16 R/W

Active power gain to produce a specified pulses per watt-hour. The value is always less than one (for example, 32,767 = 0.9999695).

3.41 MODE1_DEF

Name Bits Cof

MODE1_DEF 16 R/W

MODE default power-up settings. On power-up, this register will be read and placed into the MODE register.

3.42 CAL_STATUS

The CAL_STATUS register holds the calibration status for each individual phase. Broken down by phase, these are the values that can be calibrated. Each bit has the status of 0 = NOT Calibrated, 1 =Calibrated.

R/W-0 R/W-0 R/W-0 U-0 U-0 R/W-0 R/W-0 R/W-0

PHASE_COM

PENSATION

bit 15 bit 8

OFFSET_I_

RMS

OFFSET_V_

RMS

— — GAIN_I_RMS GAIN_V_RMS OFFSET_PO

WER_ACT

U-0 R/W-0 U-0 U-0 U-0 R/W-0 U-0 U-0

— GAIN_POW

ER_ACT

bit 7 bit 0

— — — GAIN_POWE

R_REACT

— —

Page 29

Calculation Engi ne and Register Description

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 15-0 All bits: Calibration Register Status bits

1 = This register has been calibrated 0 = This register is NOT calibrated

3.43 MAXIMUM CURRENT

Name Bits Cof

MAXIMUM_CURRENT 16 R/W

This register holds the maximum current for the meter (I

3.44 CALIBRATION_VOLTAGE

Name Bits Cof

CALIBRATION_VOLTAGE 16 R/W

This register holds the calibration voltage of the meter (V

3.45 CALIBRATION_CURRENT

Name Bits Cof

CALIBRATION_CURRENT 16 R/W

This register holds the calibration current of the meter (I

3.46 CALIBRATION_FREQUENCY

Name Bits Cof

CALIBRATION_FREQUENCY 16 R/W

MAX

CAL

This register holds the calibration frequency of the meter.

3.47 METER_CONSTANT

Name Bits Cof

METER_CONSTANT 16 R/W

This register holds the meter constant in imp/kWh or imp/kVARh.

Page 30

MCP3901 and PIC18F65J90 Energy Meter Reference De sign

3.48 CALIBRATION_LINE_CYCLE

Name Bits Cof

CALIBRATION_FREQUENCY 16 R/W

This register holds the number of line cycles used during the calibration.

3.49 GAIN_DENR_ENERGY_REACT

Name Bits Cof

GAIN_DENR_ENERGY_REACT 8 R/W

8-bit signed value. Represents the number of shifts for reactive power energy register, before GAIN_NUMR_ENERGY_REACT is applied.

3.50 GAIN_NUMR_ENERGY_REACT

Name Bits Cof

GAIN_NUMR_ENERGY_REACT 16 R/W

Reactive power gain to produce a specified pulse per VAR-hour. The value is always less than one (for example, 32,767 = 0.9999695).

3.51 PHASE_COMPENSATION_90

Name Bits Cof

PHASE_COMPENSATION_90 8 R/W

Phase delay for reactive power, signed 8-bit value, sampling time/2.

3.52 CREEP_THRSHOLD_MINUTE

Name Bits Cof

CREEP_THRSHOLD_MINUTE 8 R/W

This 8-bit register holds the decimal representation of the creep threshold time in minutes (total creep is minutes + seconds register).

3.53 CREEP_THRSHOLD_SECOND

Name Bits Cof

CREEP_THRSHOLD_SECOND 8 R/W

This 8-bit register holds the decimal representation of the creep threshold time in seconds (total creep is minutes + seconds register).

Page 31

Chapter 4. Meter Protocol and Timings

4.1 PROTOCOL

The Universal Asynchronous Receiver/Transmitter (UART) of the PIC18F65J90 is used to access the register map of the meter. In addition to the reading and writing of the registers, there are also dedicated commands for clearing calibration registers, loading calibration registers and storing calibration registers to flash. The first byte UART data is an ASCII character that represents the command, and each command has a specific protocol. Each command ends with the ASCII character “X”.

4.1.1 Command Description

The first byte of the data (byte 0) is an ASCII character E, L, S, W and R.

• E – Echo All Data Received (ECHO)

• L – Load Calibration Registers from Flash (LOAD)

• S – Store Calibration Registers (STORE)

• W – Write Bytes (WRITE)

• R – Read Bytes (READ) The last data byte is always an 'X' character. All commands will result in the same

command being returned. The exception is the 'R' (read) command which will return additional data in lieu of the number of bytes.

MCP3901 AND PIC18F65J90

ENERGY METER

REFERENCE DESIGN

4.1.1.1 “E” ECHO: - ECHO ALL DATA RECEIVED Example: 'EABCDEFGHIJKLMNOPQRSTUVWYZ1234567890X'.

Returns: 'EABCDEFGHIJKLMNOPQRSTUVWYZ1234567890X'.

4.1.1.2 “L” LOAD: LOAD CALIBRATION REGISTERS FROM FLASH. Example: 'LX'.

Returns: 'LX'.

This command is used to verify that the calibration values were actually written into flash (or E EPROM) . Once the so f twa re exe cut es a 'SX' comman d, it shou ld v erif y th at the values were stored by issuing an 'LX' command and then reading the calibration values with a 'R' command.

4.1.1.3 “S” STORE: STORE CALIBRATION REGISTERS INTO FLASH

Note that the store command will write all calibration values to internal EEPROM, and this function takes some time. During that time, the meter is not functional. The store command should only be used after calibrating the meter, and not while it is in actual use.

Example: 'SX'. Returns: 'SX'.

Page 32

MCP3901 and PIC18F65J90 Energy Meter Reference De sign

4.1.1.4 “W” WRITE: WRITE STARTING AT SPECIFIED ADDRESS Write specified bytes.

Example: 'W030000102030405060708090A0B0C0D0E0FX'. Returns: 'W030000102030405060708090A0B0C0D0E0FX'.

Note: If the number of data characters is odd, the last character (the one just prior

to the 'X') will be ignored.

Command Byte

76543210

ASCII Data

76543210

6543210

TABLE 4-1: WRITE COMMAND EXAMPLES

Description Command ASCII Command Hex

WRITE of 255d to PHA_W_OFF Register

“W 170 00 F F X” 57 31 37 30 30 30 46 46 58

FIGURE 4-1: WRITE Command Protocol.

4.1.1.5 “R” READ: READ STARTING AT SPECIFIED ADDRESS Example: 'R03010X' (read 16 bytes starting at address 30h).

Returns: 'R030000102030405060708090A0B0C0D0E0FX'

Note: For 16 bytes, there are 32 ASCII characters returned, or two characters per

byte.

3 Address Bytes (ASCII)

543210

“X” (ASCII)

76543210

7654321076543210

Command Byte

76543210

# Bytes to Read (2 Bytes ASCII)

76543210

3 Address Bytes (ASCII)

76543210 76543210

“X” (ASCII)

76543210

TABLE 4-2: READ COMMAND EXAMPLES

DESCRIPTION COMMAND ASCII COMMAND HEX

READ on ENERGY_ACT_L_RAW Register “R 0D4 06 X” 52 00 44 34 30 36 58

FIGURE 4-2: Read Command Protocol.

Page 33

Appendix A. Schematic and Layouts

A.1 INTRODUCTION

This appendix contains the following schematics and layouts for the MCP3901 and PIC18F65J90 Energy Meter Reference Design:

• Board – ADC Schematic

• Board – MCU Schematic

• Board – LCD and USB Schematic

• Board – Top Silk and Pads

• Board – Top Copper

• Board – Bottom Copper

• Board – Bottom Silk and Pads

• Board – Top 3D

• Board – Bottom 3D

MCP3901 AND PIC18F65J90

ENERGY METER

REFERENCE DESIGN

A.2 SCHEMATICS AND PCB LAYOUT

The layer order is shown in Figure A-1.

FIGURE A-1: Layer Order.

Top Layer Bottom Layer

Page 34

MCP3901 and PIC18F65J90 Energy Meter Reference De sign

A.3 BOARD – ADC SCHEMATIC

TP5

(LOW)

TP3

TP1

TP2

MPU_SDO

MPU_SCK

AFE_F0/CS

TP6

TP4

TP7

MPU_SDI

AFE_SYNC

AFE_CLKIN

GNDA

!!! DANGER!!!

AND SHOCK HAZARD

EQUIPMENT DAMAGE

MAY CAUSE EXTERNAL

CONNECTING TO J1, P1 or TP5

+3.3V

CAP-SMT-ELECTRO

C10

10uF

GNDB

C15

100nF

GNDB

OUT

GND

GNDB

MCP1700T-3302E/TT

+5V

AFE_CLKIN

AFE_DR

141516

OSC2

OSC1/CLKI

CH1+

CH1-

CH0-

NPO

100nF

NONE

CP2

MDAT1

MDAT0

AGND

REFIN/OUT+

GNDA

100nF

GNDA

GNDB

DGND

REFIN

GNDA

SSOP20

MCP3901

GNDAGNDA

GNDA

332K

300mA/150

100nF

NPO

100nF

R10

GNDB

C14

100nF

+5V +5V

C13

10UF

GNDB

C12

100nF

GNDB

OUT

GNDA

MCP1703

GND

GNDA

150

GNDB

GNDA

C11

470UF

MRA4005T3G

POWER

GNDA

+9V IN

LOW

RAPC722

MRA4005T3G

R11

100

GNDA

150 0.47uF

GNDB

BZG03C15G

GNDB

MOV1

HIGH

275VAC

CP4

CP5

GNDB

MPU_SCK

MPU_SDO

MPU_SDI

AFE_F0/CS

SDI

SDO

SCK

CH0+

RESET

DVDD

AVDD

12345

AFE_SYNC

100nF

GNDB

GNDA

100nF

1K TF

300mA/150

GNDA

NONE

CP1

CP3

Shunt GND

LINE_SHUNT2

LINE_SHUNT1

HIGH

Page 35

A.4 BOARD – MCU SCHEMATIC

Schematic and Layouts

GNDB

+3.3V

100NF

47NF

R12

R17

+3.3V

HDR6X1

C20

GNDB

C19

GNDB

C18

GNDB

C17

GNDB

LCD_4A/4F/4E/4D

LCD_4B/4G/4C/4P

LCD_3A/3F/3E/3D

LCD_1A/1F/1E/1D

LCD_2B/2G/2C/2P

LCD_2A/2F/2E/2D

LCD_3B/3G/3C/3P

GNDB

+3.3V

LCD_1B/1G/1C/1P

LCD_V/K2/R/H2

LCD_COM4

LCD_COM3

LCD_COM2

LCD_COM1

C16

NONE

10K

VSS

MPU_MCLR

GNDB

+3.3V

234

484746

RD7/SEG7

RD6/SEG6

RD5/SEG5

RD4/SEG4

RD3/SEG3

RD2/SEG2

RD1/SEG1

RD0/SEG0

/SEG31

(1)

RE6/COM3

RE5/COM2

RE4/COM1

RE3/COM0

LCDBIAS3

C21

47NF

MPU_PGD

MPU_PGC

ICD

PIC18F65J90

AFE_DR

LCD_5A/5F/RE/5D

LCD_5B/5G/5C/NC

LCD_6B/6G/6C/NC

454443

RB2/INT2/SEG9

RB1/INT1/SEG8

RB0/INT0/SEG30

RB3/INT3/SEG10

RE7/CCP2

RG1/TX2/CK2

RG0/LCDBIAS0

RE1/LCDBIAS2

RE0/LCDBIAS1

C22

47NF

C23

MPU_RG1

47NF

GNDB

SW1

+3.3V

B3S-1002P

R13

4.7K R14

100NF

MPU_RG4

4MHz

GNDB

MPU_PGC

LCD_7B/7G/7C/NC

LCD_6A/6F/6E/6D

424140

RB6/KBI2/PGC

RB4/KBI0/SEG11

RB5/KBI1/SEG29

OSC2/CLKO/RA6

PIC18F6XJ90-64TQFP

VDDCORE/VCAP

RG4/SEG26

MCLR

RG2/RX2/DT2/VLCAP1

RG3/VLCAP2

MPU_RG4

MPU_MCLR

GNDB

10UF

C26

47NF C24

MOM-NC

PUSH=HI

+3.3V

GNDB

R15

4.7K

C25

27pF

C28

GNDB

C27

27pF

MPU_SDO

MPU_SDI

MPU_PGD

+3.3V

383736

353433

VDD

RB7/KBI3/PGD

OSC1/CLKI/RA7

RC5/SDO/SEG12

RC4/SDI/SDA/SEG16

RF6/AN11/SEG24

RF4/AN9/SEG22

RF5/AN10/CVREF/SEG23

RF7/AN5/SS/SEG25

LCD_9A/0F/9E/9D

GNDB

LCD_9B/9F/9E/NC

LCD_10A/10F/10E/10D

LCD_10B/10G/AOC/NC

GNDB

MOM-NC

PUSH=HI

SW2

B3S-1002P

GNDB

C29

R16

100NF

MPU_RG1

MPU_SCK

AFE_CLKIN

RC2/CCP1/SEG13

RC3/SCK/SCL/SEG17

RF3/AN8/SEG21

RF2/AN7/C1OUT/SEG20

LCD_8A/8F/8E/8D

LCD_8B/8G/8C/NC

IR_TX

698

R20

REF

+3.3V

100NF

+3.3V

GNDB

GP1US301XP

GL100MN1MP1

RC7/RX1/DT1/SEG28

RC6/TX1/CK1/SEG27

RC0/T1OSO/T13CKI

RC1/T1OSI/CCP2/SEG12

RA4/T0CKI/SEG14

RA5/AN4/SEG15

VDD

RA0/AN0

RA1/AN1/SEG18

RA2/AN2//V

RA3/AN3/VREF+

AVSS

ENVREG

RF1/AN6/C2OUT/SEG19

MPU_RX1

MPU_TX1

IR_TX

IR_RX

+3.3V

GNDB

+3.3V

AFE_F0/CS

AFE_SYNC

MEM_CS

GNDB

C32

IR_RX

GNDB

LCD_V/K1/H1/A/W

CF_REACTIVE

CF_ACTIVE

LCD_7A/7F/7E/7D

GNDB

DNP

PC365N

698

R19

R18

1.2k

CF_ACTIVE

GNDB

SW3

B3S-1002P

MCP130

MCP130T-270/TT

+3.3V

VCC

25LC256-I/SM

MEM_CS

+3.3V

HDR2X1

GNDB

RED

GM1JR35200AE

GNDB

ACTIVE PWR

MPU_MCLR

C31

VSS

OUT

VDD

+3.3V

MPU_SCK

+3.3V

SCK

HOLD

+3.3V

MPU_SDI

C30

100NF

R22

CF_REACTIVE

100NF

MPU_SDO

VSS

GNDB

PC365N

698

R21

1.2k

GNDB

DNP

HDR2X1

GNDB

RED

GM1JR35200AE

GNDB

REACTIVE PWR

Page 36

MCP3901 and PIC18F65J90 Energy Meter Reference De sign

A.5 BOARD – LCD AND USB SCHEMATIC

LCD

LCD_3B/3G/3C/3P

LCD_3A/3F/3E/3D

LCD_4B/4G/4C/4P

LCD_4A/4F/4E/4D

LCD_5B/5G/5C/NC

LCD_5A/5F/RE/5D

LCD_6B/6G/6C/NC

LCD_6A/6F/6E/6D

LCD_7B/7G/7C/NC

LCD_7A/7F/7E/7D

LCD_8B/8G/8C/NC

LCD_8A/8F/8E/8D

LCD_9B/9F/9E/NC

LCD_9A/0F/9E/9D

LCD_10B/10G/AOC/NC

LCD_10A/10F/10E/10D

LCD_11B/11G/11C/NC

LCD_11A/AAF/11E/11D

LCD_V/K2/R/H2

LCD_V/K1/H1/A/W

3B/3G/3C/3P

3A/3F/3E/3D

4B/4G/4C/4P

4A/4F/4E/4D

5A/5F/5E/5D

6A/6F/6E/6D

7A/7F/7E/7D

8A/8F/8E/8D

9A/9F/9E/9D

V/K2/r/h2

K1h1/A/W

5B/5G/5C/NC

6B/6G/6C/NC

7B/7G/7C/NC

8B/8G/8C/NC

9B/9G/9C/NC

10B/10G/10C/NC

10A/10F/10E/10D

11B/11G/11C/NC

11A/11F/11E/11D

2A/2F/2E/2D

2B/2G/2C/2P

1A/1F/1E/1D

1B/1G/1C/1P

COM1

COM2

COM3

COM4

LCD_2A/2F/2E/2D

LCD_2B/2G/2C/2P

LCD_1A/1F/1E/1D

LCD_1B/1G/1C/1P

LCD_COM1

LCD_COM2

LCD_COM3

LCD_COM4

USB_+5V

C33

D-

0.1uF

D+

470

R23

GND

!!! DANGER !!!

AND SHOCK HAZARD

EQUIPMENT DAMAGE

MAY CAUSE EXTERNAL

CONNECTING TO J1, P1, J2 OR TP1

USB_MINIB_VERTICAL

GND

D+

D-

VSS

U10

VDD

OSC1

OSC2

GND

C34

0.1uF

VUSB

GP0/SSPND

GP1/USBCFG

RST

GP7/TxLED

GP6/RxLED

+3.3V

U11

GP2

GP5

MPU_TX1

VDD2VDD1

CTS

GP4

GP3

MPU_RX1

VIA

VOB

GND2

VOA

GND1

ADUM1201

VIB

MCP2200_RX

MCP2200_TX

RTS

MCP2200_SSOP20

R25

470

R24

GNDB

GND

+3.3V

100NF

RED

GREEN

C35

GNDB

USB_+5V

LCD1

INDIA LCD

RESONATOR-CSTCE

12 MHz

GND

Page 37

A.6 BOARD – TOP SILK AND PADS

Schematic and Layouts

Page 38

MCP3901 and PIC18F65J90 Energy Meter Reference De sign

A.7 BOARD – TOP COPPER

Page 39

A.8 BOARD – BOTTOM COPPER

Schematic and Layouts

Page 40

MCP3901 and PIC18F65J90 Energy Meter Reference De sign

A.9 BOARD – BOTTOM SILK AND PADS

Page 41

A.10 BOARD – TOP 3D

Schematic and Layouts

Page 42

MCP3901 and PIC18F65J90 Energy Meter Reference De sign

A.11 BOARD – BOTTOM 3D

Page 43

MCP3901 AND PIC18F65J90

ENERGY METER

REFERENCE DESIGN

Appendix B. Bill of Materials (BOM)

TABLE B-1: BILL OF MATERIALS (BOM)

Qty Refe rence Description Manufac turer Part Number

20 C1, C2, C5, C6

C7, C8, C12, C14, C15, C17, C18, C19, C20, C25, C29, C30, C31, C33, C34,

C35 2 C3, C4 CAP CER .1UF 25V X7R 1206 FO KEMET 1 C9 CAP .47UF 305VAC Lead Spacing 22.5

1 C10 CAP 10UF 16V ELECT FC SMD Panasonic 1 C11 CAP 470UF 25V ELECT FC SMD Panasonic - ECG EEE-FC1E471P 2 C13, C26 CAP CER 10UF 6.3V X5R 0603 Murata Electronics GRM188R60J106ME47D 5 C16, C21, C22,

C23, C24 2 C27, C28 CAP CER 27PF 50V 5% C0G 0603 TDK Corporation C1608C0G1H270J 2 D1, D2 DIODE SCHOTTKY 40V 1A SMB ON

1 D3 DIODE ZENER 15V 1.5W SMA ON Semiconductor B ZG03C15G 2 D4, D6 LED 1.6X0.8MM 625NM RED CLR SMD Kingbright Corp. APT1608EC 1 D7 LED 2X1.2MM RD/GN WTR CLR SMD Kingbright Corp. APHBM2012SURKCGKC 1 J1 CONN POWERJACK MINI R/A T/H CUI Inc. PJ-102B 3 L1, L2, L3 FERRITE 300MA 150 OHM 1806 SMD Laird-Signal

2 L4, L5 FERRITE 300MA 150 OHM 1806 SMD Laird-Signal

1 LCD1 Energy Meter LCD Display Deepakshi

1 MOV 1 VARISTOR 275V RMS 20MM RADIAL EPCOS Inc. S20K275E2 1 P1 6 X 1 Header 2.54 mm on center 6 mm/2.5 mmSamtec TSW-106-07-G-S

CAP CER .1UF 25V 10% X7R 0603 Murata

Electronics

EPCOS Inc. B32933B3474K000

mm, WxHxL = 10.5 x 16.5 x 26.5

CAP CER 47000PF 25V 10% X7R 0603 Murata Electronics GRM188R71473KA01D

Semiconductor

Integrity Products

Display Devices

- ECG EEE-FC1C100R

GRM188R71E104KA01D

C1206F104K3RACTU

MBRS140T3G

LI1806C151R-10

DP-093

1 PCB RoHS Compliant Bare PCB, MCP3901

PIC18F65J90 Shunt Meter Ref Des

1 Q1 IC REG LDO 3.3V 250MA SOT23-3 Microchip

Technology Inc. 2 R1, R2 RES 10.0 OHM 1/10W 1% 0603 SMD Panasonic - ECG ERJ-3EKF10R0V 4 R4, R5, R7,

R10

2 R8, R9 RES 332K OHM 1/4 1% 1206 SMD YAGEO Corp. RC1206FR-07332KL

RES 1.00K OHM 1/8W 1% 0805 SMD Panasonic - ECG ERJ-6ENF1001V

— 104-00342

MCP1700T-3302E/TT

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.

Page 44

MCP3901 and PIC18F65J90 Energy Meter Reference De sign

TABLE B-1: BILL OF MATERIALS (BOM) (CONTINUED)

Qty Reference Description Manufacturer Part Number

1 R11 RES 100 OHM 1W 5% 2512 SMD Panasonic - ECG ERJ-1TNF1000U 2 R13, R15 RES 4.70K OHM 1/10W 1% 0603 SMD Panasonic - ECG ERJ-3EKF4701V 2 R14, R16 RES 1.00K OHM 1/10W 1% 0603 SMD Panasonic - ECG ERJ-3EKF1001V 1 R17 RES 10.0K OHM 1/10W 1% 0603 SMD Panasonic - ECG ERJ-3EKF1002V 2 R18, R21 RES 100 OHM 1/10W 1% 0603 SMD Panasonic - ECG ERJ-3EKF1000V 2 R19, R22 RES 698 OHM 1/10W 1% 0603 SMD Rohm

Semiconductor 3 R23, R24, R25 RES 470 OHM 1/10W 1% 0603 SMD Panasonic - ECG ERJ-3EKF4700V 3SW1, SW2,

SW3

1 TP5 Wire Test Point 0.3” Length Component

1 U1 IC ENERGY METER SSOP-20 Microchip

1 U2 IC REG LDO 5V 250MA SOT-223-3 Microchip

1 U3 64/80-Pin, High-Performance Microcon-

1 U4 256K SPI Bus Serial EEPROM SOIC-8 Microchip

2 U6, U7 PHOTOCOUPLER DARL OUT 4-SMD Sharp®

1 U9 CONN RUGGED USB RCPT VERT MINI B Amphenol

1 U10 IC USB TO UART SSOP-20 Microchip

1 U11 IC ISOLATOR DIGITAL DUAL 8-SOIC Analog Devices

1 X1 CRYSTAL 4.000 MHZ 18PF SMD Abracon

1 X2 CER RESONATOR 12.0MHZ SMD Murata Electronics CSTCE12M0G55-R0

SWITCH TACT 6MM 230GF H=4.3MM Omron Electronics B3S-1002P

Corporation

Technology Inc.

Microchip

trollers with LCD Driver and nanoWatt Technology TQFP-64

Technology Inc.

Electronic Corp.

Commercial

Technology Inc.

Inc.

Corporation

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.

MCR03EZPFX6980

PJ-202-30

MCP3901AO-I/SS

MCP1703-5002E/DB

PIC18F65J90-I/PTY

25LC256-I/SN

PC36NJ0000F

MUSBB55104

MCP2200-I/SS

ADUM1201CRZ-RL7

ABLS-4.000MHZ-B4-T

TABLE B-2: BILL OF MATERIALS (COMPONENTS NOT INSTALLED)

Qty Reference Description Manufacturer Part Number

1 C32 CAP CER .1UF 25V 10% X7R 0603 — — 1 D5 DO NOT INSTALL — — 2 J2, J3 DO NOT INSTALL — — 2 R3, R6 DO NOT INSTALL — — 1 R12 DO NOT INSTALL — — 1 R20 RES 698 OHM 1/10W 0603 SMD — — 1 U5 Microcontroller Supervisory Circuit

with Open Drain Output SOT23-3

1 C32 CAP CER .1UF 25V 10% X7R 0603 — —

——

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

Page 45

Page 46

Worldwide Sales and Service

AMERICAS

Corporate Office

2355 West Chandler Blvd. Chandler, AZ 85224-6199 Tel: 480-792-7200 Fax: 480-792-7277 Technical Support:

http://www.microchip.com/ support

Web Address:

www.microchip.com

Atlanta

Duluth, GA Tel: 678-957-9614 Fax: 678-957-1455

Boston

Westborough, MA Tel: 774-760-0087 Fax: 774-760-0088

Chicago

Itasca, IL Tel: 630-285-0071 Fax: 630-285-0075

Cleveland

Independence, OH Tel: 216-447-0464 Fax: 216-447-0643

Dallas

Addison, TX Tel: 972-818-7423 Fax: 972-818-2924

Detroit

Farmington Hills, MI Tel: 248-538-2250 Fax: 248-538-2260

Indianapolis

Noblesville, IN Tel: 317-773-8323 Fax: 317-773-5453

Los Angeles

Mission Viejo, CA Tel: 949-462-9523 Fax: 949-462-9608

Santa Clara

Santa Clara, CA Tel: 408-961-6444 Fax: 408-961-6445

Toronto

Mississauga, Ontario, Canada Tel: 905-673-0699 Fax: 905-673-6509

ASIA/PACIFIC

Asia Pacific Office

Suites 3707-14, 37th Floor Tower 6, The Gateway Harbour City, Kowloon Hong Kong Tel: 852-2401-1200 Fax: 852-2401-3431

Australia - Sydney

Tel: 61-2-9868-6733 Fax: 61-2-9868-6755

China - Beijing

Tel: 86-10-8569-7000 Fax: 86-10-8528-2104

China - Chengdu

Tel: 86-28-8665-5511 Fax: 86-28-8665-7889

China - Chongqing

Tel: 86-23-8980-9588 Fax: 86-23-8980-9500

China - Hangzhou

Tel: 86-571-2819-3187 Fax: 86-571-2819-3189

China - Hong Kong SAR

Tel: 852-2401-1200 Fax: 852-2401-3431

China - Nanjing

Tel: 86-25-8473-2460 Fax: 86-25-8473-2470

China - Qingdao

Tel: 86-532-8502-7355 Fax: 86-532-8502-7205

China - Shanghai

Tel: 86-21-5407-5533 Fax: 86-21-5407-5066

China - Shenyang

Tel: 86-24-2334-2829 Fax: 86-24-2334-2393

China - Shenzhen

Tel: 86-755-8203-2660 Fax: 86-755-8203-1760

China - Wuhan

Tel: 86-27-5980-5300 Fax: 86-27-5980-5118

China - Xian

Tel: 86-29-8833-7252 Fax: 86-29-8833-7256

China - Xiamen

Tel: 86-592-2388138 Fax: 86-592-2388130

China - Zhuhai

Tel: 86-756-3210040 Fax: 86-756-3210049

ASIA/PACIFIC

India - Bangalore

Tel: 91-80-3090-4444 Fax: 91-80-3090-4123

India - New Delhi

Tel: 91-11-4160-8631 Fax: 91-11-4160-8632

India - Pune

Tel: 91-20-2566-1512 Fax: 91-20-2566-1513

Japan - Osaka

Tel: 81-66-152-7160 Fax: 81-66-152-9310

Japan - Yokohama

Tel: 81-45-471- 6166 Fax: 81-45-471-6122

Korea - Daegu

Tel: 82-53-744-4301 Fax: 82-53-744-4302

Korea - Seoul

Tel: 82-2-554-7200 Fax: 82-2-558-5932 or 82-2-558-5934

Malaysia - Kuala Lumpur

Tel: 60-3-6201-9857 Fax: 60-3-6201-9859

Malaysia - Penang

Tel: 60-4-227-8870 Fax: 60-4-227-4068

Philippines - Manila

Tel: 63-2-634-9065 Fax: 63-2-634-9069

Singapore

Tel: 65-6334-8870 Fax: 65-6334-8850

Tai wan - Hsin Chu

Tel: 886-3-5778-366 Fax: 886-3-5770-955

Taiwan - Kaohsiung

Tel: 886-7-536-4818 Fax: 886-7-330-9305

Taiwan - Taipei

Tel: 886-2-2500-6610 Fax: 886-2-2508-0102

Thailand - Bangkok

Tel: 66-2-694-1351 Fax: 66-2-694-1350

EUROPE

Austria - Wels

Tel: 43-7242-2244-39 Fax: 43-7242-2244-393

Denmark - Copenhagen

Tel: 45-4450-2828 Fax: 45-4485-2829

France - Paris

Tel: 33-1-69-53-63-20 Fax: 33-1-69-30-90-79

Germany - Munich

Tel: 49-89-627-144-0 Fax: 49-89-627-144-44

Italy - Milan

Tel: 39-0331-742611 Fax: 39-0331-466781

Netherlands - Drunen

Tel: 31-416-690399 Fax: 31-416-690340

Spain - Madrid

Tel: 34-91-708-08-90 Fax: 34-91-708-08-91

UK - Wokingham

Tel: 44-118-921-5869 Fax: 44-118-921-5820

11/29/11

Page 47

Mouser Electronics

Authorized Distributor

Click to View Pricing, Inventory, Delivery & Lifecycle Information:

Microchip: ARD00342

Microchip Technology MCP3901, PIC18F65J90 User Manual

Trademarks

Table of Contents

Preface

DOCUMENT REVISION HISTORY

Chapter 1. Product Overview

1.1 INTRODUCTION

1.2 WHAT THE MCP3901 AND PIC18F65J90 ENERGY METER REFERENCE DESIGN KIT INCLUDES

1.3 GETTING STARTED

2.1 OVERVIEW

Chapter 2. Hardware

2.2 INPUT AND ANALOG FRONT END

Chapter 3. Calculation Engine and Register Description

3.1 CALCULATION ENGINE SIGNAL FLOW SUMMARY

3.2 REGISTER LIST

3.3 MODE

3.4 STATUS

3.5 CAL_CONTROL

3.6 LINE_CYC

3.7 LINE_CYC_CNT

3.8 RAW2_I_RMS

3.9 RAW_I_RMS

3.10 I_RMS

3.11 RAW2_V_RMS

3.12 RAW_V_RMS

3.13 V_RMS

3.14 LINE_FREQUENCY

3.15 RAW_POWER_ACT

3.16 POWER_ACT

3.17 POWER_APP

3.18 RAW_POWER_REACT

3.19 POWER_REACT

3.20 PERIOD

3.21 ENERGY_ACT

3.22 ENERGY_APP

3.23 I_ABS_MAX

3.24 V_ABS_MAX

3.25 ENERGY_REACT

3.26 PHASE_COMPENSATION

3.27 OFFSET_I_RMS

3.28 OFFSET_V_RMS

3.29 GAIN_I_RMS

3.30 GAIN_V_RMS

3.31 OFFSET_POWER_ACT

3.32 GAIN_POWER_ACT

3.33 OFFSET_POWER_REACT

3.34 GAIN_POWER_REACT

3.35 GAIN_ENERGY_ACT

3.36 GAIN_ENERGY_APP

3.37 GAIN_ENERGY_REACT

3.38 CF_PULSE_WIDTH

3.39 GAIN_DENR_ENERGY_ACT

3.40 GAIN_NUMR_ENERGY_ACT

3.41 MODE1_DEF

3.42 CAL_STATUS

3.43 MAXIMUM CURRENT

3.44 CALIBRATION_VOLTAGE

3.45 CALIBRATION_CURRENT

3.46 CALIBRATION_FREQUENCY

3.47 METER_CONSTANT

3.48 CALIBRATION_LINE_CYCLE

3.49 GAIN_DENR_ENERGY_REACT

3.50 GAIN_NUMR_ENERGY_REACT

3.51 PHASE_COMPENSATION_90

3.52 CREEP_THRSHOLD_MINUTE

3.53 CREEP_THRSHOLD_SECOND

Chapter 4. Meter Protocol and Timings

4.1 PROTOCOL

Appendix A. Schematic and Layouts

A.1 INTRODUCTION

A.2 SCHEMATICS AND PCB LAYOUT

A.3 BOARD – ADC SCHEMATIC

A.4 BOARD – MCU SCHEMATIC

A.5 BOARD – LCD AND USB SCHEMATIC

A.6 BOARD – TOP SILK AND PADS

A.7 BOARD – TOP COPPER

A.8 BOARD – BOTTOM COPPER

A.9 BOARD – BOTTOM SILK AND PADS

A.10 BOARD – TOP 3D

A.11 BOARD – BOTTOM 3D