Feb 2007 Microsolutions Microchip

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www.microchip.com Microcontrollers • Digital Signal Controllers • Analog • Serial EEPROMs

IN THIS ISSUE

PAGE 1

Introducing the New Microchip

Advanced Product Selector

Software

PAGE 2

Join Microchip at ESC!

PAGE 3

Software configurable CRC on the

PIC24 Devices

PAGE 4

Microchip Achieves ZigBee™

Compliant Platform Designation

PAGE 5 Discover the Digital

Potentiometers Design Guide

PAGE 6

New 25XX320A Serial EEPROMs

PAGE 7

EDN’s Hot 100 Products List

Features Three Microchip Devices

PAGE 8

Get Started with Two New PICkit™

Development Tools

PAGE 9

Bit Bashing: Build a Switcher

Out of Peripherals Built Into a

Microcontroller

PAGE 11

Production Programming throughmicrochipDIRECT

Microchip’s Regional Training

Centers

PAGE 12

Microchip Around Town

PAGE 13

What’s New in Microchip

Literature?

PAGE 14

Web Site Highlights

Introducing the Microchip Advanced Product Selector

(MAPS) Version 2.0 Software

What is MAPS? Why use it? The new Microchip Advanced Product Selector (MAPS) Version2.0 has debuted online, providing a comprehensive selectiontool for Microchip’s complete product portfolio including analog,memory, microcontrollers and digital signal controllers. MAPS isavailable at the Microchip web site and can be downloaded in

electronic form.MAPS makes it even easier to find the right Microchip productfor your design requirements. This online database incorporatesan interactive GUI, allowing online parametric searches and easynavigation through Microchip’s product portfolio with the use oftabs, filters and search features.

The tool provides side-by-side comparison of products as well.

It also provides invaluable cross references to competitiveinformation and pricing on designated product families – with theability to obtain the most up-to-date collateral and information

with online access. Visit the MAPS web site at www.microchip.com/MAPS

for more information!

ENTER TO WIN!Check out our new

Digital Power Contest!

http://www.microchip.com/


http://www.surveymonkey.com/Users/93010988/Surveys/817373032707/36FF39ED-7703-46DE-BDF0-C03F3B77F331.asp?U=817373032707&DO_NOT_COPY_THIS_LINK



http://www.microchip.com/MAPS

http://www.microchip.com/MAPS






MICROCHIP TECHNOLOGY’S microSOLUTIONS eNEWSLETTER - February 2007

www.microchip.com Microcontrollers • Digital Signal Controllers • Analog • Serial EEPROMs 2

RETURN TO FRONT PAGETo register for our training sessions, please visit www.microchip.com/ESC

Introduction to Digital Power Converter Design Using the dsPIC® DigitalSignal Controller Family for SMPS: This class introduces the design andimplementation of a digital mode synchronous buck DC/DC converter

using the dsPIC DSC family for SMPS. The SMPS PWM, ADC, and analogcomparator modules, combined with the dsPIC DSC processor, enablesthe creation of power conversion circuits utilizing digital control loops. Thisclass discusses the SMPS peripherals and their use in an actual circuit,along with their integration with the control loop software.

MPLAB® REAL ICE™ In-Circuit Emulator Demonstration: This classdemonstrates the features and advantages of Microchip’s next generationhigh speed emulation system, the MPLAB REAL ICE. The MPLAB REAL ICEfeatures real-time, full speed emulation and fast programming of MicrochipFlash MCU and DSC devices. Real-time variable watch and trace analysisare just two of the many features, all for under $500.

LeCroy Solutions for Debugging and Validating USB and Ethernet Designs: LeCroy oscilloscopes and protocol analyzers enable engineers to design, testand validate high-performance electronic systems faster and more efficiently.This class focuses on LeCroy solutions for debugging and validating USBand Ethernet designs. Come see the equipment utilized by Microchip in theirRegional Training Center classes.

Mechatronics Defined: As technology advances, designs that were oncepurely mechanical are now best done with electronics or a combination ofboth. This class explores what mechatronics is, the role PIC®microcontrollersare playing and the benefits of mechatronic designs verses mechanicaldesigns. Mechatronics is broken down at the system level so that you can

study the components necessary for your design.

ZigBee™ and MiWi™ Protocols: Discussion of ZigBee™ protocol andMicrochip stack capabilities as well as an introduction to Microchip’s ownwireless MiWi™ protocol. The MiWi protocol is available free of charge and

is ideal for users not needing full protocol interoperability.Ethernet Solutions from Microchip: Ethernet’s capabilities and ubiquitousdeployment make it unrivaled among communications standards. This classpresents Microchip’s cost-effective and easy-to-use Ethernet products,software and development tools including our 28-pin stand-alone Ethernetcontroller, our family of PIC18F microcontrollers with Ethernet peripheral andfree TCP/IP stack. Learn how to add Ethernet capability to your embeddeddesign.

16 bit Microcontroller and Digital Signal Controller Product FamilyOverview: If you’re an embedded designer looking for high-performanceproducts coupled with a solid migration strategy, this class shows you

the benefits of using one software development environment to programeverything from your simplest 6-pin, 8-bit microcontroller to the industry’shighest performing 16-bit microcontrollers and digital signal controllers.Technical experts will showcase the architectural and peripheral features ofMicrochip’s new 16-bit microcontroller and digital signal controller families.

Analog Sensor Conditioning in Embedded Systems: Most sensor circuitsrequire some analog signal conditioning before conversion to digital. Thisclass provides background information on several types of sensors andsensor conditioning circuits, including active filters. Three common sensors,thermistor (temperature), photodiode (light) and capacitance (humidity) andtheir conditioning circuits, are detailed. A demonstration of filter designsgenerated by Microchip’s FilterLab®software is included.

Microchip is excited to be back at ESC this year with a variety of training sessionsavailable daily at the Microchip booth. For a complete class schedule, please visit our web site.






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The ability to ensure that data is communicated correctly between and within today’s systemsis becoming more important as the number, speed and complexity of communication optionsincreases. While many of the more sophisticated communications peripherals have implementedsome form of check sum calculations, Microchip has implemented a software-configurable CyclicRedundancy Check (CRC) on the PIC24F microcontrollers. The CRC is used by a programmer

to calculate an extremely robust checksum that can be attached to a data string or comparedto the checksum attached to a data string. If the checksums match, the data is assumed to becorrect.

A checksum calculation can be as simple as adding the data together but simple methods areoften less robust than a designer would require. The Microchip Cyclic Redundancy Check is asoftware-configurable CRC that uses two polynomials, one derived from the data and a secondselected by the user as a generator or divisor to produce a robust and unique checksum. TheCRC process is iterative and would consume considerable CPU power. The PIC24F CRC requiresvery little CPU support for the checksum calculation.

Features and Benefits of the PIC24F Cyclic Redundancy Check:

• Programmable CRC generator polynomial * Allows designer to select the generator polynomial best suited to their data.• Programmable polynomial length

* Sets Checksum Length• Interrupt Output * Indicates when checksum complete * Allows CPU to continue operation while checksum is being calculated• 8 Word/16 Byte FIFO * Allows small block of data to be preloaded * Allows large (unlimited) block checksums to be calculated

The CRC on the PIC24F is implemented as a stand alone peripheral. This allows the peripheral to be used for any purpose desired by the programmer. The CRCincludes an 8 word or 16 Byte FIFO. This allows the PIC24F to load small blocks of data into the FIFO, initiate the conversion, and read the checksum whenthe interrupt is tripped. Larger blocks of data can be processed by polling the CRC Control register and writing additional data when space is available in theFIFO.

Potential uses for CRC

• Used with SPI, UART and I²C™ to determine if received data is correct• Used with block of memory to determine if a value has been corrupted• Used with UART to ensure IrDA®protocol and X-modem communications are correct

Check out the Software-Configurable Cyclic Redundancy Check (CRC) on the PIC24F

For more information, please visit our www.microchip.com/PIC24





RETURN TO FRONT PAGEFor more information, please visit our Wireless Networking Design Center at www.microchip.com/ZigBee

Microchip Technology Achieves ZigBee™ Compliant Platform Status for the Combination

of its MRF24J40 IEEE 802.15.4 Radio and PIC18 MCUs

Microchip has achieved the ZigBeeCompliant Platform designation fromthe National Testing Service and theZigBee Alliance, for the combination

of its MRF24J40 IEEE 802.15.4 RFtransceiver and the PIC18 family ofhigh-end 8-bit Flash microcontrollers.Additionally, Microchip offerscompliant development tools andcompliant source code for its royalty-free, no-cost license, ZigBee protocolstack. The ZigBee Compliant Platformdesignation means that you can useMicrochip’s semiconductors to buildproducts that inter-operate over a

ZigBee protocol wireless network.According to In-Stat, the market for

IEEE 802.15.4 wireless Personal Area Networking via the ZigBee specificationnetwork layer and other proprietary protocols could grow 200% by 2009 – withannual shipments surpassing 150 million units in 2009. Microchip addressesthe needs of this market with the only zero-cost-license and royalty-freeZigBee protocol stack, which provides a source-code format that allows youto customize your product utilizing Microchip’s broad portfolio of compliantPIC18 microcontrollers, which offer a wide range of options – with 32 Kbytesto 128 Kbytes of Flash program memory in 28- to 100-pin packages.

Microchip’s MRF24J40 transceiver is a highly integrated RF transceiver. Thisradio also offers low power consumption and performance that exceeds allIEEE 802.15.4 specifications, with full Media Access Controller (MAC) supportand an Advanced Encryption Standard (AES) hardware encryption engine.In addition to supporting the ZigBee protocol, this transceiver supportsMicrochip’s free MiWi™ protocol – a small-footprint protocol developed byMicrochip for customers who do not need ZigBee protocol interoperability.

Microchip’s IEEE 802.15.4 wireless networking development

Microchip’s complete

ZigBee Compliant Platform

includes free stack with

source code, development

tools, 2.4 GHz IEEE

802.15.4 transceiver and

high-end 8-bit MCUs.

tools have been upgraded to ensure ZigBee protocol

compliance.

Available tools include the ZENA™ Wireless Network Analyzer (part #DM183023), which uses a simple graphicalinterface to configure the free MicrochipZigBee and MiWi protocol stacks. Thisenables customers to reduce the code sizeof the stacks by removing optional features;cuts development time by simplifying theinteractions with the stacks; and allowscustomization of the stack to fit a particularneed. Consisting of both hardware and

software, the ZENA wireless network analyzer is an IEEE 802.15.4 protocolanalyzer that is capable of decoding ZigBee and MiWi protocol packets – from

the lowest layers to the top of the stack (including the security modules). Thenetwork-configuration display window allows users to see the traffic in realtime, as it travels from one node to another. A session can also be saved toa file, to allow further analysis of all the network traffic.

The ZENA tool can be purchased separately, or as part of the PICDEM™ Z

2.4 GHz Demonstration Kit (part # DM163027-4). The PICDEM Z is an easy-to-use evaluation and development platformfor IEEE 802.15.4 application designers.The kit includes all of the hardware,software source code and printed circuitboard (PCB) layout files needed to rapidlyprototype wireless products. Additionally,an instructional application note is available

from Microchip’s online Connectivity Design Center.






Looking for Design Ideas for Your Digital Potentiometer Application?

Check out our new Digital Potentiometers Design Guide for design

ideas supporting digital potentiometer applications, including:

mechanical potentiometer replacement, amplifiers with offset

and trimming, band pass filtering with offset and gain trimming,

programmable filter, Whetstone bridge trimming and generalembedded system design techniques.

Microchip offers a range of devices that allow you to select a product thatbest fits your application. Some of the selection options include:

• A wide range of resistor values: RAB resistance (typical) from 2.1 kΩto 100 kΩ

• Step resolution: 6/8-bit• Serial Interfaces: Up/Down/SPI• Memory Types: Volatile/Non-volatile• Resistor Network Configurations: Potentiometer (Resistor divider)/

Rheostat (Variable resistor)• Single/Dual Potentiometer Options• Package Options• Special Features: Shutdown Mode/WiperLock™ Technology

• Low Voltage, Low Power Options

Resistor sizes and resolutions allow the designer to select the step resistanceand number of steps. For the device with the resistance (RAB) equal to2.1 kΩ, there are 64 steps (63 resistors), so the step resistance (RS) equalsRAB/63 (or 33.33Ω). Now at the other end of the spectrum, for the devicewith the resistance (RAB) equal to 50 kΩ, there are 64 steps (63 resistors),so the step resistance (RS) equals RAB/63 (or 793.65Ω).

The serial interface options allow you to easily integrate the device into theapplication. For some applications the simple Up/Down interface will beadequate, while for other applications the SPI interface will better meet yoursystem requirements.

The availability of both volatile and non-volatile devices gives you flexibilityin optimizing the application. Some applications may use the digitalpotentiometer as a replacement for a mechanical potentiometer. In this case,a non-volatile device with the serial interface connecting to the test hardwareinterface allows a low cost device with low cost manufacturing.

Resistor Network configurations allow the package size/cost to be minimizedfor the desired functionality. If a variable resistor (rheostat) with one terminal

tied to ground is desired, then only one resistor terminal (the wiper) needsto be implemented. In the MCP402X family, this configuration is shown inthe MCP4024 and allows the functionality to be achieved in the low-costSOT-23-5 package. The potentiometer pinout with all terminals availablerequires an 8-pin package.

Dual potentiometer options allow you to have potentiometers/variableresistors that are closely matched in the system, since the two devices areon the same device die.

Packaging options help you to address your system requirement trade-offsincluding device cost, board area and manufacturing sites (surface mount vs.

thru-hole). Packages include tiny 3x3 SOT-23 and 3x2 DFN packages.Microchip offers several boards that support the demonstration and evaluationof the digital potentiometer devices. These boards fall into two categories:populated boards to demonstrate/evaluate the specific device(s) and blankprinted circuit boards (PCBs). The blank PCBs allow you to populate the deviceand supporting circuit to best evaluate the performance and characteristicsof the desired device configuration. To see which boards are available, pleasevisit the Microchip web site at: www.microchip.com/analogtools.

To download this design guide, please visit

ww1.microchip.com/downloads/en/DeviceDoc/22017a.pdf

http://ww1.microchip.com/downloads/en/DeviceDoc/22017a.pdf

http://ww1.microchip.com/downloads/en/DeviceDoc/22017a.pdf






Microchip’s 25AA320A and 25LC320A

(25XX320A) devices are capable of speedsup to 10 MHz and enable you to easily upgrade32 Kbit designs to 10 MHz, while enjoyingMicrochip’s high endurance, quality, on-time

delivery and short lead times.The 25XX320A SPI serial EEPROMs providefast byte- and page-level erase and writeoperations, as well as rapid data-access times.

They are built on Microchip’s proprietary PMOSElectrically Erasable Cell (PEEC) architecture,which enables high-density devices to beplaced in small packages, while maintaininghigh endurance (1 million erase/write cycles),industry-leading retention time (200 years) and

the ability to operate at high speeds even in harsh environments. Examples of such environmentsinclude the high temperatures found in automotive applications.

The new devices fit easily into existing sockets and provide an instant upgrade path,as well as an excellent second source for customers wanting more speed at the32 Kbit memory density level.

The same development tools that support all of Microchip’s memory products can be used with the25LC320A and 25AA320A devices. These include the SEEVAL® 32 Serial EEPROM Designer’s Kit (Part # DV243002), which enables quick and easy development of robust, reliable serial EEPROM-based applications. The kit is available today for just $99.99 and includes:• Microchip’s Total Endurance™ software model

• SEEVAL 32 developer board and user-interface software• Serial cable and power supply • Serial EEPROM sample pack• SEEVAL 32 Quick Start Guide

Total Endurance software is a powerful and easy-to-use tool for modeling and designing serial EEPROMapplications. The software takes the guesswork out of determining the life of a serial EEPROM devicein an embedded design. Design trade-off analysis that formerly consumed days or weeks can now beaccomplished in minutes, with a level of accuracy that delivers a truly robust design.

The 25XX320A serial EEPROMs are offered in 8-pin PDIP, SOIC, MSOP packages, as well as standardand non-standard (rotated) TSSOP package pinouts. This helps you easily upgrade from past versions,

or drop the new devices into existing sockets designed for other 32 Kbit SPI devices without boardchanges.

Microchip Expands Its 32 Kbit SPI Serial EEPROM Family with High-speed, 10 MHz Devices

For more information about Microchip’s

serial EEPROM offering, take a look at

the Serial EEPROM Cross Reference

Guide available online at http://ww1.

microchip.com/downloads/en/DeviceDoc/21621d.pdf .

Microchip’s serial EEPROM products are compatible with threestandard serial bus types and support densities that range

from 128 bits up to 1 Mbits. These bus types include the I²C™,

Microwire and SPI, which are the most commonly used busesfor this product type. As Microchip’s EEPROMs are compatible

with the de facto industry standards, they can be used asdrop-in replacements for competitor devices in most cases. Bysupporting a wide operating voltage range from 1.8 volts up to

5.5 volts, most applications are supported. For new designs,Microchip’s value-added features include smaller footprints,lower power consumption, lower voltage levels, faster bus

rates and higher endurance levels than many other commoditydevices.

For more information about Microchip’s serial EEPROM

devices, please visit www.microchip.com/memory.

http://ww1.microchip.com/downloads/en/DeviceDoc/21621d.pdf












EDN magazine has named the MCP6G01 and MCP6G02 gain-selectable amplifiers,

the dsPIC3OF1010/202X family of digital-signal controllers and the PIC18F97J60 8-bitmicrocontrollers to this year’s list of winners in

its annual Hot 100 Products issue. EDN’s staff

of technical editors analyzes and comparesthe industry’s product introductions and makes its selections at the end of each

year. Read about all the products in EDN’s December 15, 2006 issue and atwww.edn.com/2006hot100 .

Products that appear in EDN’s annual Hot 100 Products issue are chosen by itseditors from the hundreds of newsworthy items that grace the pages of EDN, whether

they appeared in EDN’s New Products section, a feature story or an online exclusive.The list encompasses a range of architectures and technologies and a plethora ofcategories – from analog ICs to multimedia to test-and-measurement tools. Microchip’s

products appear in the analog ICs power and processors categories.

The MCP6G01 and MCP6G02 gain-selectable amplifiers

use one pin to select a gain of one, 10 or 50, resulting inbandwidths of 900 kHz, 350 kHz and 250 kHz, respectively.

The gain pin can be floated, yielding the third gain settingand gain selection adjusts internal compensation. Quiescentcurrent is 110 μA. The internal gain-setting resistors also give

a gain accuracy of better than 1%. CMOS-process technologylimits the maximum operating voltage to 5.5V, but the partoperates on 1.8V for mobile-system and other low-voltage

applications.

Microchip’s dsPIC30F1010/202X family relies on the company’s digital signal controlengine to deliver a complete digital-power-control loop

with 1 ns PWM resolution and 2 Msps performance fromits built-in 10-bit ADC. Unlike digital power controllersthat rely on a dedicated hardware PID controller, thechips do not adhere to any one control algorithm or

topology. In addition, direct communication between theADC, the PWM and the analog comparators in the formof a configurable control fabric allows you to configure

their intercommunication upon start-up. The partsalso have multiple analog comparators that allow you

to select from a variety

of input references tomodify the behavior ofthe PWM generators –

Three of Microchip’s Products Named to EDN’s Hot 100 Products of 2006

for example, to assert the output of the PWMgenerator for feed-forward compensation.

The PIC18F97J60 family of processors

reduces the board space and bill-of-materialscosts for 8-bit embedded-system applicationsneeding Ethernet connectivity by reducing

extra chips for the Ethernet MAC (media-access-control) and PHY) layers. This familyof 8-bit microcontrollers includes a complete

IEEE 802.3-compliant Ethernet controllerthat comprises a MAC, a PHY, an 8 Kbytetransmitter/receiver-RAM buffer and a free

TCP/IP (Transfer Control Protocol/Internet Protocol) software stack in a singlepackage. The nine members of the processor family target industrial and buildingautomation, as well as commercial and home-control applications. The PIC18F97J60

devices are available now at prices starting at $4.24 (10,000) in 64-, 8- and 100-pinRoHS-compliant TQFPs.

In addition to the PIC18 microcontroller core and on-chip 10-BaseT MAC and PHYwith an Ethernet buffer, key features of these devices include 128 Kbytes of Flash; 4

kbytes of SRAM; a 16-channel, 10-bit ADC; five 10-bit PWMs; two comparators; twoLIN (Local Interconnect Network) UARTs; and two I²C™/SPI peripherals. The Ethernetcontroller supports programmable pattern-match, filtering and wake-up. These devices

are available for the industrial-temperature range of -40 to +185°C. These devicessupport seamless migration to add Ethernet support to PIC18 designs.

The TCP/IP stack is a royalty-free, no-cost license that is portable to all PIC18microcontrollers and is available as a download from Microchip. It has a code footprint

of approximately 25 Kbytes and the MPLAB® C18 and HI-TECH Compilers fromMicrochip and HI-TECH Software, respectively,

support the stack. Microchip offers the AN833and AN870 application notes for the TCP/IPstack and SNMP (Simple Network ManagementProtocol) agent, respectively. The PICDEM.net™

2 Demonstration Board (DM163024) is availablenow for $165. The demonstration board enablesdevelopers to evaluate the new PIC18F97J60

devices as well as the discrete-componentconfiguration of a PIC18 microcontroller with theENC28J60 Ethernet controller.

ENTER TO WIN!

Check out our newDigital Power Contest!










The PICkit Serial Analyzer isa low-cost tool with an easy-

to-use interface which performscommunication between aPC-controlled USB port and variousserial ports. This is useful forcommunicating with circuits thatare embedded deep within systems electrically or mechanically with onlyserial port access. It is also useful for emulating serial circuitry capable of

communicating with a PIC®microcontroller. The PICkit Serial Analyzer hardwaresupports I2C™, SMBus, SPI and USART protocols.

The PICkit Serial Analyzer comes complete with a development boardthat contains Microchip’s 28-pin PIC16F886 Flash microcontroller. Thismicrocontroller contains firmware to emulate several functions typically foundin serial systems. The PICkit Serial Analyzer can be used to exercise thesefunctions and display the data.

The PICkit Serial Analyzer also includes software that allows communicationbetween a Windows® PC and the serial protocol of the device under test.Scripts can be created and saved, and custom templates can be created tocustomize the software to the functionality of the device. A special page inthe software is customized for the 28-pin demonstration board included in thekit. The software DLL can also be accessed by any software that needs thepower of serial communication through the USB port. The software offers thefollowing features and functionality:

• Reading and writing in four protocols: I²C, SMBus, SPI & USART

• Script building

• Template customization

• Demo board testing

• DLL, which can be used in custom applications

PICkit™ Serial Analyzer

For more information, please visit www.microchip.com/DevelopmentTools

Microchip’s PICDEM™ System

Management Kit is a low-costdemonstration and training

tool designed for individualsinterested in system integrationand design of a variety ofapplications. System integrationrefers to the consolidation ofmultiple systems into a singlesystem.

In conjunction with the PICkit™

Serial Analyzer (included in the kit), communication to the emulated deviceson the bus can be managed and monitored. The PICkit Serial Analyzer is a

low-cost development tool that allows communication between a PC and theserial protocol of the system under test.

The PICDEM System Management Board provides an I²C™ communicationsbus typically found in applications, such as personal computers or rack mountservers. The bus connects to multiple devices used to monitor and record thehealth and status of a computer system. The board integrates the functionsof a dedicated Real-Time Clock (RTC), serial EEPROM, thermal managementcontroller and analog-to-digital converter into a single PIC® microcontroller.The board is populated with Microchip’s Mid-Range PIC16F886 device, whichsupports the following components or functions:

• MCLR and switch, interrupt pushbutton switches

• 4 LEDs

• I²C communications(SDA & SCL)

• USART communications(TX & RX)

• In-Circuit Serial Programming™(ICSP™) programming pins

PICkit™ System Management Kit

• PWM output fan control• Fan tachometer input line

• Heating element control line

• Temperature sensor input line from

MCP9700

• 32.768 kHz crystal clock(T1OSO & T1OSI)

• 3V lithium battery backup

C h e c k o u t t h e s e n e w d e v t o o l s !






In model aircraft parlance, kit bashing is defined as the practice of

using the materials from a kit for one aircraft to build a similar, butdifferent, aircraft. So, bit bashing is the process of using the featuresof one or more simple peripherals to build a more complex custom

peripheral.

This month’s Bit Bash:

I need another supply Other than VDD

I have a CCP, Makes it easy as ABCWritten by: Keith Curtis, Principal Applications Engineer

In many applications, the power supply voltage is often dictated by an

external design constraint such as battery voltage, bus-powered USB orsomething as mundane as a single-output, low-cost wall wart. Unfortunately,these are also the applications that usually have a requirement for anadditional supply that is not compatible with VDD. If the additional supply islower, then an LDO solves the problem, but if it is higher, we have to go to aswitcher.

While Microchip does make a line of switching regulators which fill this needquite nicely, there are some applications in which it is preferable to build theswitcher out of peripherals built into the microcontroller. Over the course ofthe next few issues of microSOLUTIONS, we will examine how some of theon-chip peripherals can be used to create an impromptu switching regulator.

For our first example, we will take a look at a simple hysteresis-feedbackboost circuit using a comparator and the PWM function in the CCP. Theboost topology is used to generate a higher output voltage than the sourcevoltage – so in this example, we are generating a supply voltage greaterthan VDD.

To build a switching regulator, you need a few things: a power switch, aninductor, a capacitor, a gated pulse generator, a voltage reference anda feedback path. In this example, the CCP will be our pulse generator,the 0.6V comparator reference will be our voltage reference, and thecomparator will be our feedback. Figure 1 shows the circuit for our switching

power supply, using the comparator and the CCP in PWM mode. The CCPgenerates the switching pulse, which turns on/off the switch Q1. D1 acts

Bit Bashing; The practice of combining peripherals, external components and rmwareto create a new function, feature or peripheral (slang)

as the second half of the switch, connecting the inductor to the outputduring the discharge portion of the cycle. C1 accumulates the current flowfrom the inductor, smoothing out the pulses into a DC level. R1, R2, thecomparator and the 0.6V reference form the feedback path. When thedivided output voltage is less than 0.6V, then the comparator allows pulses

from the CCP through the resistor to turn Q1 on. If the divided output isgreater than, or equal to, the 0.6V reference, the comparator shorts out thepulses by grounding the gate through a diode, and preventing the systemfrom generating too high an output voltage. Figure 1 shows the waveformsgenerated both when the system has a low output, and when the system isat the desired voltage.

Note: the pull down resistor on the gate of the MOSFET is to hold thetransistor off until the microcontroller configures the CCP and comparator.

Figure 1 Boost Topology Schematic

Continued on next page.

MICROCHIP TECHNOLOGY’S i SOLUTIONS NEWSLETTER F b 2007






Note: if the CCP has the auto-shutdown feature, the resistor on theoutput of the CCP and the diode on the output of the comparator arenot required, and the output of the comparator is connected to the CCPinternally.

Now, given that we have the circuit, we have to calculate a few componentvalues. The first is the duty cycle of the boost circuit, which is determinedby the source and output voltages. Equation 1 determines the minimum

duty cycle required. Note: the duty cycle can be, and should be, a littlelarger than the value determined by Equation 1. The process of skippingpulses, based on the feedback, will reduce the average duty cycle to theoptimal value when the system is running.

Equation 1 DutyCycle >= 1 – (VDD / VOUT)

The next value to determine is the inductance of the inductor; to simplifythe calculation, we will first determine IRIPPLE, and then the size of theinductor. Equation 2 determines the necessary ripple current to keep theinductor current discontinuous (the inductor current goes to zero duringthe pulse cycle).

Equation 2 IRIPPLE = (2 x IOUT-MAX) / (1 – DutyCycle)

Given IRIPPLE, Equation 3 determines the necessary inductor value giventhe input voltage, the desired output voltage, the desired output current,and the switching frequency. One thing to note about the switchingfrequency (F SWITCH), it should be above 30 kHz to keep it inaudible andbelow 250 kHz to give a reasonable resolution for the PWM duty cycle (<=6.25%, assuming Fosc = 4 MHz)

Equation 3 Inductor = (VDD x DutyCycle) / (IRIPPLE x F SWITCH)

The inductor chosen for the design should also have a saturation current

at least two times IRIPPLE to prevent saturation and the violent failure ofthe MOSFET transistor.

The third value is the capacitance of the output capacitor C1. Thiscapacitor acts as a filter, smoothing the pulse currents delivered fromthe inductor, into a DC voltage. To calculate the value, we need to knowthe maximum allowable output voltage ripple for the circuit. As this isdetermined by the load, the value must be supplied by the designer. Usingthis value, Equation 4 will determine the minimum capacitance required.

Equation 4 C1 >= (IRIPPLE x VRIPPLE) / (2 x PI x F SWITCH)

One note on C1, while electrolytic capacitors are less expensive than

Tantalum capacitors, electrolytic capacitors begin to act inductive above50 to 100 kHz. If the switching frequency is much above 30 to 50 kHz,

the added cost of the tantalum is often necessary to reduce switchingnoise in the output.

Three final choices must be made in the design; the minimum ratings forQ1 and D1, and the two resistors R1 / R2.

Q1 should be rated for 2 x IRIPPLE and the gate charge QTOT should be keptas small as possible. If it is over 20-50 nC, or the source voltage to theboost circuit is greater than VDD, it will be necessary to use a MOSFET

driver to boost the gate drive current/voltage. Note: low gate drive willresult in the MOSFET transistor spending a large portion of each cyclein its linear region and that will drop efficiency and heat the transistor.Likewise, the current rating for the diode should be rated for 2 x IRIPPLE.

R1 and R2 form a voltage divider, and are chosen to produce a feedbackvoltage of 0.6V when the output voltage of the circuit is at the desiredvoltage. See Equation 5.

Equation 5 R2 = ((VOUT – 0.6V) x R1) / 0.6V

So, with a little math, a few components, and a spare peripheral or two, itis possible to generate a supply voltage greater than VDD.

Bit Bashing: Continued from previous page.

For more information, please visit the Intelligent Power Supply Design Center at

www.microchip.com/power.







How much are you paying to program your PIC® microcontroller?

Come to

microchipDIRECT

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can do for youtoday!

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S a m p l e P r i c i n g

Example Device Package Type Quantity Programmed microchipDIRECT

Programming Charge

PIC10F202-I/OT 6-Lead SOT-23 5001+ $0.02 each

PIC16F630-E/SL 14-Lead SOIC 5001+ $0.08 each

PIC16F627A-I/SS 20-Lead SSOP 5001+ $0.10 each

PIC16F57-I/SP 28-Lead PDIP 5001+ $0.12 each

PIC18F4520-I/ML 44-Lead QFN 5001+ $0.20 each

PIC18F8722-I/PT 80-Lead TQFP 5001+ $0.23 each

Stay Ahead of the Competitionwith Technical Training fromMicrochip! Throughout the Company’s history,Microchip has focused on offeringsuperior technical support. We haveachieved this through a number ofdifferent programs and initiatives. Oneof those has been the establishment of34 Regional Training Centers, which arenow operational worldwide to providemore customized training for engineerson a continual basis worldwide.

Regional Training Centers, or RTCs, are conveniently located high-techengineering labs equipped with the most current embedded controltools, techniques and instructors. The RTCs conduct hands-on beginner,intermediate and advanced classes on Microchip’s product lines to helpcustomers speed up their development time and lower their total systemcost.

The RTCs offer classes on a variety of highly targeted design topics thatcan help engineers add functionality to their current applications and takefull advantage of new or unfamiliar device peripherals. These classes canhelp them keep current in the competitive world of embedded controland stay ahead of industry trends and design techniques. The smallclass sizes allow plenty of time for one-on-one interaction with the expertinstructors. In the words of a recent attendee, “It was an enjoyable andinformative series of seminars, all well done, and I really appreciated thewillingness of the staff to adapt the material to our interests.”

The RTC team can also provide on-site group training. They can customizeany curriculum to meet the groups’ specific needs and arrive with allpresentation materials and equipment.

All of these efforts by the worldwide Microchip RTC team are part of ourrelentless commitment to provide our customers with the best and mosttimely technical training.

www.microchip.com/RTC


https://www.microchipdirect.com/programming/default.aspx























http://www.microchipdirect.com/






Microchip Around TownMicrochip is also participating in thefollowing events:

Applied Power Electronics Conference (APEC)

February 25 – March 1, 2007 • Disneyland® Hotel, Anaheim, CA

http://www.apec-conf.org

Keith Curtis is scheduled to present a hands-on seminar entitled “Designing Intelligent PowerSupplies” on Feb. 26 from 8:30 AM to noon. Attend this session to find out what a microcontrollercan do for you and your power-supply design. To cover important information concerning thedesign process, software design methods will also be presented. These methods include codereuse to shorten development times, hardware abstraction for more readable and maintainablecode, a systematic methodology for easier design and testing, and a simple technique forbuilding software that multitasks without the expense of an operating system.

Join panelist Sean Strickler in a discussion about “Doing Business On-line” on February 28,2007 from 8:30 to 10:15 AM.

Battery Power 2007 June 6 – 7, 2007 • Denver, CO

http://www.batterypoweronline.com/bp07_program.htm

Keith Curtis presents “Super Capacitors – The Next Rechargeable Battery?” This presentationexplains the use of super capacitors as an energy-storage medium, using a solar-basedemergency power reference design as an example. The goal of the system is to providecontinuous power to the emergency system during both day and night hours. The design willshow how super-capacitor-based storage will be tasked with automatically charging when energyis available, providing power when energy is not available from the solar panels and providingshort-term, panel support in times of high current draw.

Microchip will host a half-day pre-conference workshop on June 5, 2007. Terry Cleveland, StaffEngineer for Microchip’s Analog & Interface Products Division is scheduled to present a four-hour seminar that explains the development of linear- and switching-charger designs.

2007 American Society for Engineering Education (ASEE) Annual Conference & Exposition

June 24 – 26, 2007 • Honolulu, HI

http://www.asee.org/conferences/annual/2007/index.cfm

John Magrane and Professor Lakshmi Munukutla from Arizona State University are scheduledto present a paper that demonstrates how industry and academia can develop programs toassist universities in attracting students and ensure a pipeline of highly skilled business-readygraduates. Not only will these programs help academia and industr y, but also provide studentswith a superior education and improved employment prospects.

Principal Application Engineer Keith Curtis is scheduled to present “Embedded Software DesignMethodology to Help Students Succeed in the Real World,” and Microchip’s Carol Popovichwill co-present a paper with Professor Lakshmi Munukutla of ASU entitled “Universities andIndustry Can Partner to Create Engineering Entrepreneurs.

Managing Power, Ground, Noise in Microcontroller/Analog ApplicationsThursday (April 5, 2007) 2:00pm – 3:30pm

Salon 1 & 2/Marriott

https://www.cmpevents.com/ESCw07/a.asp?option=C&V=11&SessID=4377

Join Microchip’s Keith Curtis and learn guidelines for sign, component selection and PWB

layout for combining fast logic, power and sensitive analog in a common design. Microcontroller

applications often have low-level sensor signals and moderate power-drive circuitry. Peaceful

coexistence among these three extremes requires a careful power and ground distribution

design. This paper will discuss sources of noise and the paths by which it travels, the theory

behind good layout practices and their impact on noise and the proper selection and placement

of noise-isolating and limiting components. Designers wanting to keep digital and power noise

out of sensitive input circuits will find this paper useful.

Designing Embedded Systems that Use Shared Modules

Thursday (April 5, 2007) 11:00am – 12:30pm

Almaden Ballroom 2/Hilton


Microchip’s Senior Embedded Software Engineer, Sean Justice, will show you how to identify, place

and use shared modules in a multi-application embedded system. Many embedded syste ms

have multiple applications, such as a system that contains a boot loader to place itself in a

known safe state, while at the same time uploading the system’s main application. This paper

will discuss how multi-application embedded systems can utilize shared modules to decrease

the amount of system resources used. How to identify shareable modules and where to place

them will be discussed, as well as how to make shared modules accessible by all applications.

High-Quality Speech Compression Without RoyaltiesThursday (April 5, 2007) 11:00am – 12:30pm

Salon 1 & 2/Marriott


Priyabrata Sinha, Senior Applications Engineer at Microchip, will help you gain familiarity with

some key royalty-free speech compression techniques that are suitable for implementation on

low-cost embedded systems such as Digital Signal Controllers (DSCs).His paper describes an

inexpensive speech compression technique using the open-source “Speex” algorithm, based on

a variant of the Codebook Excited Linear Prediction (CELP) compression technique. The paper will

discuss A-law and µ-law commanding as specified by the ITU G.711 standard and ADPCM-based

compression based on the ITU G.726A standard. Design examples showing implementation of

these techniques using dsPIC®digital signal controllers will be presented, and an overview of

applications requiring speech compression and decompression will be provided.

Join Microchip

in the following

technical sessions

at ESC!

MICROCHIP TECHNOLOGY’S microSOLUTIONS eNEWSLETTER February 2007




















What’s New in Microchip Literature?Visit our Technical Documentation page onwww.microchip.com to view the documents.

Type ofDocument

Title of Document DS# Location

ApplicationNotes:

Fixed-Point Trigonometry Using CORDIC MathFunctions Application Note 01061A Web

IR Remote Control Application Note 01064A Web

DataSheets:

dsPIC33FJ12GP201/202 Data Sheet 70264A Web

PIC18F87J11 Family Data Sheet 39778A Web

PIC18F1220/1320 Data Sheet 39605E Web

PIC18F4321 Family Data Sheet 39689D Web

PIC18F2220/2320/4220/4320 Data Sheet 39599E Web

PIC18F2450/4450 Data Sheet 39760B Web

PIC18F2X1X/4X1X Data Sheet 39636C Web

PIC18F2585/2680/4585/4680 Data Sheet 39625C Web

PIC18F2682/2685/4682/4685 Data Sheet 39761B Web

24XX1025 Data Sheet 21941D Web

24C01 Data Sheet 21201F Web

24AA01/LC01B Data Sheet 21711F WebPIC12F629/675 Data Sheet 41190D Web

ProductBriefs

PIC16F72X Product Brief 41308A Web

Erratas:

dsPIC30F1010/202X Rev. A1 Silicon Errata 80290D Web

PIC18F2480/2580/4480/4580 Rev. A1 Silicon 80219B Web

PIC18F2585/2680/4585/4680 Rev. A1 Silicon 80202D Web

PIC18F6625/6621/8525/8621 Rev. A1 SiliconErrata 80163D Web

PIC18F6585/8585/6680/8680 Rev. A1 SiliconErrata 80162D Web

PIC16F87/88 Rev. C0 Silicon Errata 80301A Web

PIC18F2420/2520/4420/4520 Rev. B2 SiliconErrata 80288D Web

Timer1 Module Silicon Errata 80233C Web

PIC16F6XX Rev. A Silicon Data Sheet Errata 80243G Web

PIC16F610/616/16HV610/616 Data SheetErrata 80296B Web

PIC16F506 Rev. B Silicon Data Sheet Errata 80300A Web

TechnicalBriefs:

Interfacing Micro Crystal MS1V-T1K Tuning ForkCrystal Tech. Brief 91097A Web

User Guides

PICkit™ Serial Analyzer User Guide 51647A Web

MCP9800 Temperature Data Logger Demo Board

2 User Guide 22027A Web

Type ofDocument

Title of Document DS# Location

Misc.Documents:

dsPIC33F Family Reference Manual - Sect. 6:Interrupts 70184A Web

PIC24H Family Reference Manual - Sect. 22:Direct Memory Access (DMA) 70223A Web

dsPIC33F Family Reference Manual - Sect. 7:Oscillator 70186A Web

dsPIC33F Family Reference Manual - Sect. 16:Analog-to-Digital Converter (ADC) 70183A Web

dsPIC33F Family Reference Manual - Sect. 21:ECAN 70185A Web

Packaging Outlines and Dimensions 00049AL Web

PIC24F Family Reference Manual, Sect. 4:Program Memory 39715A Web

PIC24F Family Reference Manual, Sect. 33:Programming and Diagnostics 39716A Web

PIC24F Family Reference Manual, Sect. 3: DataMemory 39717A Web

PIC24F Family Reference Manual, Sect. 1:Introduction 39718A Web

PIC24F Family Reference Manual, Sect. 32: High-Level Device Integration 39719A Web

Parallel VID Code to Serial VID Code TranslationImplementation on PIC16F506 White Paper 41309A Web

Collateral

Low-Cost Tools Solutions Brochure 51560D Print/Web

Development Tools IDE Brochure 51549C Print/Web

PICDEM™ System Management Kit ProductOverview

51625A Print/Web

PICkit™ Serial Analyzer Product Overview 51629A Print/Web

MPLAB®REAL ICE™ Product Overview 51630A Print/Web

PIC18F Development Tools Product Over view 39673C Print/Web

Automotive Analog Products Design Guide 01005B Print/Web

Operational Amplifiers Product Overview 21691C Print/Web

Stand-Alone Analog and Interface SolutionsBrochure

21060K Print/Web

Analog and Interface Tech. Documentation CD 51205H CD

PGA, Op Amps and Comparators Design Guide 21861C Print/Web

Digital Potentiometer Design Guide 22017A Web

Purchasing HDCP Compliant EEPROM WafersBrochure

22000A Print/Web

8-bit Baseline and Mid-Range PIC®MCU Map 41271B Print/Web

High-Performance PIC24 MCU Family Brochure 39754B Print/Web

K EELOQ®CD 40038D CDRETURN TO FRONT PAGE

MICROCHIP TECHNOLOGY’S microSOLUTIONS eNEWSLETTER February 2007

http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=84














web site HIGHLIGHTS

Save Shipping Costs

By DownloadingDevelopment Software from

microchipDIRECTmicrochipDIRECT now provides a “software for sale” download capability. You canpurchase Microchip’s embedded-development software quickly and easily from

www.microchipdirect.com. The first Microchip products being offered throughthis service are the popular MPLAB® C18 and MPLAB C30 C Compilers. Thesecompilers are full-featured and ANSI compliant, and download with extensive libraries

for embedded-development applications using

Microchip’s PIC18 high-end 8-bit and PIC24 16-bitfamilies of microcontrollers, as well as the dsPIC®

digital signal controllers. More software products areexpected to be added in the future. Microchip alsointends to work with third-party software vendors to

offer their software tools and libraries for downloadon microchipDIRECT.

MPLAB C18 and MPLAB C30 C compilers are fullyintegrated with Microchip’s free MPLAB Integrated

Development Environment (IDE). Both compilersgenerate relocatable object modules, which can

be linked with assembly modules or in-line assembly code to generate reusable codemodules for any embedded application. The MPLAB IDE provides a comprehensivegraphical front end to leverage code development with the MPLAB C18 and MPLABC30 compilers via a project manager, a programmer’s text editor and a rich suite of

robust debugging tools. Extensive multi-pass optimizations generate compact, robustcode that can be directly downloaded to Microchip’s microcontrollers using Microchip’sprogrammers, in-circuit debuggers and in-circuit emulators. Both compilers generate

re-entrant code and support third-party tools, such as Real-Time Operating Systems(RTOSs) and application-specific libraries.

A free Student Edition of each compiler is also available for evaluation download

from the Microchip web site at www.microchip.com/c30 and www.microchip.

com/c18, respectively. For additional information, contact any Microchip salesrepresentative or authorized worldwide distributor, or visit Microchip’s main web site at

www.microchipdirect.com.

With no shippingcosts involved,downloading software from microchipDIRECTcan also be aconvenient way tosave money on yourtoolkit.

Did you know?That Microchip offers many code examples for digital signalcontroller products?? Visit www.microchip.com/code to

view the list.

Need Technical Support TODAY? If you need quick answersto your technical questions,then please contact our 24/7Technical Support site at:

http://support.microchip.com.

In addition, Microchip is hiringadditional field applicationsresources in your area, who canwork with you on your individualneeds. Contact your local Microchipsales office for more details.

The Microchip name and logo, the Microchip logo, Accuron, dsPIC, K EELOQ, microID, MPLAB, PIC, PICmicro, PICSTART, PRO MATE, PowerSmart, rfPIC and SmartShunt

are registered trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. AmpLab, FilterLab, Migratable Memory, MXDEV, MXLAB,

SEEVAL, SmartSensor and The Embedded Control Solutions Company are registered trademarks of Microchip Technology Incorporated in the U.S.A. Analog-for-

the-Digital Age, Application Maestro, CodeGuard, dsPICDEM, dsPICDEM.net, dsPICworks, ECAN, ECONOMONITOR, FanSense, FlexROM, fuzzyLAB, In-Circuit Serial

Programmi ng, ICSP, ICEPIC, Linear Active Thermisto r, Mindi, MiWi, MPASM, MPLIB, MPLINK, PICkit, PICDEM, PICDEM.net, PICLAB, PICtail , PowerCal, PowerInfo,

PowerMate, PowerTool, REAL ICE, rfLAB, rfPICDEM, Select Mode, Smart Serial, SmartTel, Total Endurance, UNI/O, WiperLock and ZENA are trademarks of Microchip

Technology Incorporated in the U.S.A. and other countries. SQTP is a service mark of Microchip Technology Incorporated in the U.S.A. All other trademarks

mentioned herein are property of their respective companies. ©2007, Microchip Technology Inc.





Feb 2007 Microsolutions Microchip

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