|
|
(20 intermediate revisions by 14 users not shown) |
Line 1: |
Line 1: |
− | [http://acacia-dealbata.ednskies.info/ acacia dealbata seeds] [http://recipes-low-carb.eutocia.info/ atkins carb diet low recipe] [http://nursing-agencies.clairce.info/ nursing agencies] [http://carlitadennis.ifrance.com/blog/epson-ink-cartridges.htm epson ink cartridges] [http://olivaboatner.ifrance.com/library/ragdoll-kittens.html cat kitten ragdoll] [http://assignment-agreement.matelot.info/ assignment agreement] [http://metrakit.matelot.info/ metrakit] [http://the-mask-costumes.scutari.info/ the mask costumes] [http://tamcaston.ifrance.com/blog/ez-pass.html ez pass] [http://gay-cowboy-gallery.minimite.info/ gay cowboy gallery] [http://shareecoulter.ifrance.com/directory/gma.html gma channel 7] [http://lacreshamellott.ifrance.com/ff8.htm ff8 walk through] [http://janettgleaves.22web.net/resources/laker-head-coach.html laker head coach] [http://apartment-available.matelot.info/ apartment available florida fort in myers] [http://janettgleaves.22web.net/resources/pu-li.html pu li] [http://lizakratz.22web.net/comments/blondes-in-thongs.html blondes in thongs] [http://breannpeabody.totalh.com/three-six-mafia.htm three six mafia] [http://jane-says.poptone.info/ jane says] [http://tamcaston.ifrance.com/blog/college-hunk.html college hunk] [http://peachtree-doors.eutocia.info/ peachtree doors] [http://ruthashores.totalh.com/small/online-business.html online business tax filing] [http://jean-peters.dotlike.info/ jean peters actress] [http://swimming-shorts.charpit.info/ swimming shorts] [http://alfa-157-pictures.ednskies.info/ alfa 157 pictures] [http://janettgleaves.22web.net/resources/gumball.html gumball] [http://sex-good.clairce.info/ sex good] [http://john-davis-artist.dotlike.info/ john davis artist] [http://austin-texas.reprime.info/ austin, texas] [http://louveniacarreir.totalh.com/phoenix-apartments.htm phoenix apartments] [http://asx-file-format.poptone.info/ asx file format] [http://kyongbremer.ifrance.com/styles/rooster-rock.html park rock rooster state] [http://lizakratz.22web.net/comments/mermaid-melody.html mermaid melody video] [http://joananoon.22web.net/mercy-me-here-with.html mercy me here with me tabs] [http://maria-carey-songs.minimite.info/ maria carey songs] [http://squirrel-trap.minimite.info/ squirrel trap georgia] [http://shareecoulter.ifrance.com/directory/jupiter-florida.html florida hotel jupiter] [http://tamcaston.ifrance.com/blog/arizona-land.html arizona land for sale] [http://kyongbremer.ifrance.com/styles/grand-theft-auto.html grand theft auto san andreas cheat codes] [http://97-point-power.dotlike.info/ 97 point power viewer] [http://esther-price-cincinnati.poptone.info/ esther price cincinnati] [http://dumb-people.minimite.info/ dumb people video] [http://joananoon.22web.net/mixman-bbs.html mixman bbs] [http://louveniacarreir.totalh.com/jensen-satellite.htm jensen satellite radio] [http://shareecoulter.ifrance.com/directory/owl-cross-word.html owl cross word puzzles] [http://michelledolph.22web.net/call-customer.html call customer center service practices relationship] [http://carlitadennis.ifrance.com/blog/alimta-mesothelioma.htm alimta mesothelioma pemetrexed treatment] [http://ticket-printing.clairce.info/ company printing ticket us] [http://elviralook.totalh.com/q/private-equity.html private equity business services] [http://breannpeabody.totalh.com/leeson-motor-wiring.htm leeson motor wiring] [http://close-up-vulva.reprime.info/ close up vulva] [http://la-fitness-harrisburg.eutocia.info/ la fitness harrisburg pa] [http://resort-quest.eutocia.info/ resort quest maui] [http://lizakratz.22web.net/comments/rich-girls.html rich girls] [http://kristlepoplin.22web.net/html/conference-calls.html conference calls] [http://olivaboatner.ifrance.com/library/steam-locomotive.html steam locomotive sound effects] [http://cellulite-lotion.poptone.info/ anti cellulite lotion] [http://breannpeabody.totalh.com/er-season-4-dvd.htm er season 4 dvd release] [http://evangelinaqueve.totalh.com/small/thirdplace-books.html thirdplace books] [http://pantry-shelving.clairce.info/ pantry shelving] [http://almetaplum.ifrance.com/view/series.html poker series world] [http://elviralook.totalh.com/q/web-site-planning.html web site planning guide] [http://geico-direct.eutocia.info/ direct geico insurance� �car] [http://kyongbremer.ifrance.com/styles/apogee-face.html north face apogee jacket] [http://alan-smith.poptone.info/ alan smith] [http://lacreshamellott.ifrance.com/paradise-post.htm paradise post office] [http://kristlepoplin.22web.net/html/old-roses-china.html old roses china] [http://marcy-playground.charpit.info/ marcy playground] [http://engina-heart.reprime.info/ engina heart] [http://andy-sipowicz.eutocia.info/ andy sipowicz] [http://evangelinaqueve.totalh.com/small/sacred-harp-singing.html sacred harp singing texas] [http://breannpeabody.totalh.com/self-image-profiles.htm self image profiles] [http://carlitadennis.ifrance.com/blog/pharmaceutical-company.htm pharmaceutical company massachusetts] [http://joananoon.22web.net/mutualism.html mutualism] [http://kristlepoplin.22web.net/html/auto-rental-bismarck.html auto rental bismarck north dakota] [http://janettgleaves.22web.net/resources/maggots.html maggots] [http://teenagers-sucking.charpit.info/ teenagers sucking dicks] [http://louveniacarreir.totalh.com/klawitter.htm klawitter] [http://joananoon.22web.net/increasing-sperm.html increasing sperm mobility] [http://carlitadennis.ifrance.com/blog/samsung-plasma.htm 42 plasma samsung] [http://kyongbremer.ifrance.com/styles/brand-development.html brand development] [http://breannpeabody.totalh.com/xxx-live-cam.htm xxx live cam] [http://free-virtual.ednskies.info/ free game pet virtual] [http://appunti-informatica.ednskies.info/ appunti informatica libera] [http://joananoon.22web.net/school-girls.html school girls in mini skirts] [http://elviralook.totalh.com/q/val.html val] [http://ruthashores.totalh.com/small/pocket-knifes.html pocket knifes] [http://3b-cancer-cervix.minimite.info/ 3b cancer cervix] [http://kristlepoplin.22web.net/html/andre-vincelli.html andre vincelli] [http://olivaboatner.ifrance.com/library/map-east-hartford.html map east hartford ct] [http://evangelinaqueve.totalh.com/small/ancient-greek-olympics.html ancient greek olympics] [http://free-woodworking.poptone.info/ free woodworking plans] [http://janettgleaves.22web.net/resources/interpid-museum.html interpid museum] [http://arranged-divorce.reprime.info/ arranged divorce marriage rate] [http://louveniacarreir.totalh.com/2006-academy.htm 2006 academy awards nominee best songs] [http://los-lobos-song.poptone.info/ los lobos song lyrics] [http://mp3-player-with.matelot.info/ mp3 player with compact flash card] [http://olivaboatner.ifrance.com/library/furs.html fur psychedelic] [http://elviralook.totalh.com/q/tsi.html tsi] [http://breannpeabody.totalh.com/jenny-mccarthy-cinderela.htm jenny mccarthy cinderela] [http://joananoon.22web.net/wish-you-were-here.html wish you were here itv] [http://tamcaston.ifrance.com/blog/makefile-include.html makefile include library] [http://wimbledon-champion.eutocia.info/ wimbledon champion michael 1991] [http://elviralook.totalh.com/q/personalized.html personalized apparel] [http://lizakratz.22web.net/comments/heat-treating.html heat treating metal] [http://pounding.eutocia.info/ pussy pounding] [http://janettgleaves.22web.net/resources/the-great-gatsby.html the great gatsby nick] [http://almetaplum.ifrance.com/view/jackyl.html jackyl] [http://elviralook.totalh.com/q/vw-bug-parts.html vw bug parts] [http://tamcaston.ifrance.com/blog/jeffrey-moore.html jeffrey moore basketball] [http://louveniacarreir.totalh.com/operaties.htm operaties] [http://michelledolph.22web.net/mlk.html mlk] [http://tamcaston.ifrance.com/blog/paint-thickness.html paint thickness measurement] [http://simply-weight.minimite.info/ simply weight loss] [http://evangelinaqueve.totalh.com/small/intel-stock.html intel stock] [http://yin-yang-symbol.minimite.info/ yin yang symbol] [http://ricco-act-law.eutocia.info/ ricco act law] [http://googles.matelot.info/ gmail googles] [http://kristlepoplin.22web.net/html/virtual-dj-studio.html virtual dj studio 3.02 serial] [http://lcd-wall-mount.dotlike.info/ lcd wall mount] [http://almetaplum.ifrance.com/view/home-improvement.html home improvement loan northern rock] [http://lizakratz.22web.net/comments/bondage-fairies.html bondage fairies comic] [http://tamcaston.ifrance.com/blog/verizon-phone-promotion.html verizon cell phone promotion] [http://carlitadennis.ifrance.com/blog/law-on-maternity.htm law on maternity leave] [http://kyongbremer.ifrance.com/styles/hairy-jock-guys.html hairy jock guys] [http://olivaboatner.ifrance.com/library/em-get-jeezy.html em get jeezy lyric] [http://louveniacarreir.totalh.com/magnavox-dvd.htm magnavox dvd player manual] [http://plus-size-tea.dotlike.info/ dress length plus size tea wedding] [http://julies-erving.charpit.info/ julies erving biography] [http://schoolnotescom.dotlike.info/ schoolnotes.com] [http://microchip-semiconductor.poptone.info/ microchip semiconductor] [http://kristlepoplin.22web.net/html/piaggio-nrg-power.html piaggio nrg power reviews] [http://evangelinaqueve.totalh.com/small/seduction-techniques.html seduction techniques for men] [http://beagle.minimite.info/ beagle dog] [http://evangelinaqueve.totalh.com/small/savings-account.html savings account] [http://almetaplum.ifrance.com/view/zufi-alexander.html zufi alexander] [http://lacreshamellott.ifrance.com/salvage-car-dealers.htm salvage car dealer in miami] [http://janettgleaves.22web.net/resources/enchantedlearning.html enchantedlearning] [http://lacreshamellott.ifrance.com/broome.htm broome] [http://ruthashores.totalh.com/small/ping-pong-vagina.html ping pong vagina] [http://olivaboatner.ifrance.com/library/potter-piano-movers.html potter piano movers] [http://almetaplum.ifrance.com/view/crossroads.html crossroads mall] [http://coleman-trailers.reprime.info/ coleman tent trailer] [http://mesothelioma.poptone.info/ canada legislation mesothelioma] [http://essay-outline.ednskies.info/ essay outline] [http://radnor-fire.minimite.info/ radnor fire company] [http://janettgleaves.22web.net/resources/online-web-site.html online web site design builder] [http://kyongbremer.ifrance.com/styles/indorama-synthetics.html indorama synthetics india limited] [http://las-vegas-grand.eutocia.info/ las vegas grand canyon vacations] [http://pulaski-county-prosecuting.reprime.info/ pulaski county prosecuting attorneys office] [http://kyongbremer.ifrance.com/styles/federal-job-search.html usa federal job search] The vast majority of electronic systems operate at some fixed frequency.
| + | The vast majority of electronic systems operate at some fixed frequency. |
| Usually the component that fixes that frequency is a quartz crystal, sealed in a metal can. | | Usually the component that fixes that frequency is a quartz crystal, sealed in a metal can. |
− | (Some very-low-cost devices might use a "ceramic resonator" (made of high-stability piezoelectric ceramics, generally lead zirconium titanate)or a resistor and a capacitor to fix the frequency. ). | + | (Some very-low-cost devices might use a "ceramic resonator" (made of high-stability piezoelectric ceramics, generally lead zirconium titanate) or a resistor and a capacitor to fix the frequency. ). |
| | | |
− | The entire circuit that generates the frequency is called an "oscillator", includes the resonant part (crystal, resonator, or RC), some capacitors, and a silicon chip and therefore is called a hybrid device. | + | The entire circuit that generates the frequency is called an "oscillator", includes the resonant part (crystal, resonator, or RC), some capacitors, and a silicon chip and is therefore called a hybrid device. |
| (An oscillator that uses a resistor and a capacitor to fix the frequency is called a "RC oscillator". | | (An oscillator that uses a resistor and a capacitor to fix the frequency is called a "RC oscillator". |
| An oscillator that uses a crystal to fix the frequency is called a "crystal oscillator".) | | An oscillator that uses a crystal to fix the frequency is called a "crystal oscillator".) |
Line 11: |
Line 11: |
| Oscillators usually come in a metal can, but Epson also encapsulates them in plastic. Typically an oscillator can has 4 pins. Inside the can is all the components of the oscillator. One applies DC power on 2 of the pins, and the oscillating signal (the "CLK OUT") appears on another pin. (The remaining pin is unused). | | Oscillators usually come in a metal can, but Epson also encapsulates them in plastic. Typically an oscillator can has 4 pins. Inside the can is all the components of the oscillator. One applies DC power on 2 of the pins, and the oscillating signal (the "CLK OUT") appears on another pin. (The remaining pin is unused). |
| | | |
− | An oscillator can also be made from scratch using crystal in a (2-pin) metal can, a couple of capacitors, an resitor and an inverter. | + | An oscillator can also be made from scratch using crystal in a (2-pin) metal can, a couple of capacitors, a resistor and an inverter. |
| In either case, the frequency is printed on the top of the crystal or oscillator. | | In either case, the frequency is printed on the top of the crystal or oscillator. |
| | | |
Line 20: |
Line 20: |
| | | |
| In systems with multiple CPUs, it is often simpler, cheaper, and more reliable (avoiding metastability problems) to use a single crystal (rather than a dedicated crystal for each CPU). | | In systems with multiple CPUs, it is often simpler, cheaper, and more reliable (avoiding metastability problems) to use a single crystal (rather than a dedicated crystal for each CPU). |
− | CPUs (and many other components) often have a single "CLK" pin designed to be connected to the wire used to send tha | + | CPUs (and many other components) often have a single "CLK" pin designed to be connected to the wire used to send that "clock signal" (a fixed frequency) everywhere. |
− | 1000
| |
− | t "clock signal" (a fixed frequency) everywhere.
| |
| | | |
| Unfortunately, many people confuse the "clock signal" generated by an oscillator (a simple metronome beat, tone, at constant frequency) with far more complicated "clock system"s that keep track of seconds, minutes, hours, and sometimes days, weeks, months, and years. | | Unfortunately, many people confuse the "clock signal" generated by an oscillator (a simple metronome beat, tone, at constant frequency) with far more complicated "clock system"s that keep track of seconds, minutes, hours, and sometimes days, weeks, months, and years. |
| | | |
− | == for further reading == | + | The "negative resistance test" measures the oscillation allowance of a crystal oscillator circuit. |
| + | Most manufacturers recommend that the oscillation allowance of the circuit be at least five times the maximum resistance value of the quartz crystal unit used in the circuit.<ref> |
| + | [http://www.ti.com/lit/an/slaa322b/slaa322b.pdf "MSP430 32-kHz Crystal Oscillators"]. |
| + | p. 5. |
| + | </ref><ref> |
| + | [http://www.foxonline.com/pdfs/osctheoryoper.pdf "Oscillator Theory of Operation"]. |
| + | p. 109. |
| + | </ref><ref> |
| + | [http://www.sii.co.jp/en/quartz/circuit-design/ "Oscillation Circuit Design Overview"]. |
| + | </ref><ref> |
| + | [http://www.atmel.com/images/doc8333.pdf "AVR4100: Selecting and testing 32kHz crystal oscillators for Atmel AVR microcontrollers"]. |
| + | p. 12. |
| + | </ref><ref> |
| + | [http://www.ecsxtal.com/store/pdf/Oscillation-Circut-Design-Considerations.pdf "Oscillator Circuit Design Considerations"]. |
| + | p. 8 |
| + | </ref> |
| + | |
| + | |
| + | |
| + | == Further reading == |
| | | |
| * [http://techref.massmind.org/techref/clocks.htm massmind: clocks] | | * [http://techref.massmind.org/techref/clocks.htm massmind: clocks] |
| * [http://en.wikipedia.org/wiki/Crystal_oscillator Wikipedia: crystal oscillator] | | * [http://en.wikipedia.org/wiki/Crystal_oscillator Wikipedia: crystal oscillator] |
− | * [http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE | + | * [http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1824&appnote=en021190 "App Note AN949: Making Your Oscillator Work" by Brett Duane] |
| + | * [http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1824&appnote=en020706 "App Note AN943: Practical PICmicro® Oscillator Analysis and Design" by Ruan Lourens] |
| + | * [http://www.icmfg.com/technicaldata.html#crystal_data Crystal data] |
| + | [[Category:Components]] |
The vast majority of electronic systems operate at some fixed frequency.
Usually the component that fixes that frequency is a quartz crystal, sealed in a metal can.
(Some very-low-cost devices might use a "ceramic resonator" (made of high-stability piezoelectric ceramics, generally lead zirconium titanate) or a resistor and a capacitor to fix the frequency. ).
The entire circuit that generates the frequency is called an "oscillator", includes the resonant part (crystal, resonator, or RC), some capacitors, and a silicon chip and is therefore called a hybrid device.
(An oscillator that uses a resistor and a capacitor to fix the frequency is called a "RC oscillator".
An oscillator that uses a crystal to fix the frequency is called a "crystal oscillator".)
The oscillator includes, in addition to the frequency-fixing component just mentioned, an amplifier and capacitors.
Oscillators usually come in a metal can, but Epson also encapsulates them in plastic. Typically an oscillator can has 4 pins. Inside the can is all the components of the oscillator. One applies DC power on 2 of the pins, and the oscillating signal (the "CLK OUT") appears on another pin. (The remaining pin is unused).
An oscillator can also be made from scratch using crystal in a (2-pin) metal can, a couple of capacitors, a resistor and an inverter.
In either case, the frequency is printed on the top of the crystal or oscillator.
Many microcontrollers have 2 pins (typically labeled "XTAL1" and "XTAL2", or "OSC1" and "OSC2", or something similar)
that are designed to be directly connected to the 2 pins of a crystal.
(Capacitors from those pins to VCC and GND are also part of the recommended circuit).
An inverter inside the microcontroller acts as the amplifier, and the crystal and capacitors make up the rest of the oscillator. Microcontrollers when connected directly to a crystal need to have capacitors attached that need to be percisely matched with other circuit components on the board. Resonators tend to have the capacitor buildin reducing the amount of trial and error of capacitor selection.
In systems with multiple CPUs, it is often simpler, cheaper, and more reliable (avoiding metastability problems) to use a single crystal (rather than a dedicated crystal for each CPU).
CPUs (and many other components) often have a single "CLK" pin designed to be connected to the wire used to send that "clock signal" (a fixed frequency) everywhere.
Unfortunately, many people confuse the "clock signal" generated by an oscillator (a simple metronome beat, tone, at constant frequency) with far more complicated "clock system"s that keep track of seconds, minutes, hours, and sometimes days, weeks, months, and years.
The "negative resistance test" measures the oscillation allowance of a crystal oscillator circuit.
Most manufacturers recommend that the oscillation allowance of the circuit be at least five times the maximum resistance value of the quartz crystal unit used in the circuit.<ref>
"MSP430 32-kHz Crystal Oscillators".
p. 5.
</ref><ref>
"Oscillator Theory of Operation".
p. 109.
</ref><ref>
"Oscillation Circuit Design Overview".
</ref><ref>
"AVR4100: Selecting and testing 32kHz crystal oscillators for Atmel AVR microcontrollers".
p. 12.
</ref><ref>
"Oscillator Circuit Design Considerations".
p. 8
</ref>
Further reading[edit]