JYE Tech DSO112A User manual

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JYE Tech-1-www.jyetech.com
DSO112ADigital Oscilloscope
UserManual
ApplicableModels:11201A,11202A, 11203A
ApplicableFirmwareVersion:113-11201-211orlater(forU1)
Before FirstTime Use...................................................................................................................3
Introduction...........................................................................................................................................3
PackingContents...................................................................................................................................3
Switchon Battery..................................................................................................................................3
ChargeBattery.......................................................................................................................................4
AutoPower-off......................................................................................................................................4
Paneland Connectors....................................................................................................................4
MainWorkingScreen............................................................................................................................4
Connectors.............................................................................................................................................5
PowerButton.........................................................................................................................................6
BasicOperations...........................................................................................................................6
PowerOn/Off........................................................................................................................................6
ProbeaSignal........................................................................................................................................6
StateNavigation....................................................................................................................................7
BootingSequence..................................................................................................................................7
AdjustSensitivityand Couple...............................................................................................................8
AdjustTimebase....................................................................................................................................8
SetupTrigger.........................................................................................................................................8
ExternalTrigger...................................................................................................................................10
TriggerLevel.......................................................................................................................................10
AdjustVerticalPosition.......................................................................................................................10
AdjustHorizontalPosition...................................................................................................................10
HoldState............................................................................................................................................10
SelectRecordLength...........................................................................................................................10
TestSignalOutput...............................................................................................................................10
Advanced Operations..................................................................................................................11
VPosAlignment...................................................................................................................................11
SaveWaveform....................................................................................................................................11
Recall Waveform.................................................................................................................................11
SendWaveformData...........................................................................................................................12
RestoreFactoryDefault.......................................................................................................................15
Save/Recall Presets..............................................................................................................................15
Rename Presets....................................................................................................................................16
EnterDashboard..................................................................................................................................16
SelectTestSignalFrequency...............................................................................................................16
TCursors...........................................................................................................................................17
VCursors..........................................................................................................................................17
FrequencyMeasurement......................................................................................................................17
VoltageMeasurements.........................................................................................................................17
ChangeAuto-offTime.........................................................................................................................17
SerialInterface (SI).....................................................................................................................18
Introduction.........................................................................................................................................18
OutputofCapturedData......................................................................................................................19
OutputofMeasurements......................................................................................................................20
CommandsandTheir Returns.............................................................................................................21
CSVWaveformFileFormat................................................................................................................27
Use asIntegration Module..........................................................................................................29
Connectors...........................................................................................................................................29
Dimensions..........................................................................................................................................30
Maintenance................................................................................................................................31
ChargeBattery.....................................................................................................................................31

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TouchPanelCalibration.......................................................................................................................31
FirmwareUpgrade...............................................................................................................................32
Troubleshooting..........................................................................................................................35
OscilloscopeDoes Not TurnOn..........................................................................................................35
WhiteScreen.......................................................................................................................................35
TouchPanelNoReaction....................................................................................................................35
Specifications..............................................................................................................................35
AppendixA:Coded ValuesofOscilloscope Parameters.............................................................36
1)ValuesofTimebase.............................................................................................................36
2)ValuesofTriggerMode......................................................................................................36
3)ValuesofTriggerSlope.......................................................................................................36
4)ValuesofCouple.................................................................................................................37
5)ValuesofVerticalSensitivity..............................................................................................37
Revision History..................................................................................................................................37

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BeforeFirstTimeUse
Introduction DSO112Aisbasedon DSO112withre-designed schematicand
PCB.Whilekeepingall functionsandperformance ofits
predecessorit exhibitssignificantlyhigherverticalsensitivityand
ultralowbackgroundnoises.Asasmall,light,accurate, and
batteryoperated oscilloscope DSO112Aisbestforportableor
field use.
Packing Contents Checkpackingcontentsbased on skunumberand the
followingtable.
11201A 11202A
DSO112A
Oscilloscope 1 1
MCX-Clip
Probe2 2
USBCable 1 1
Battery 1
Switch on Battery Fortransportationsafetythe batterywasdisconnected bya
switchpriortoshipping.Thisswitch mustbe turnedon before
thebatterycanbeused. Theswitchlocatesinside theenclosure
closetothe top-leftcorner(seethe nexttwophotos).Itcan be
turned onbyslideittowardsthe USBconnectorwithasmall
stickthroughtheslotattop-left corneroftheenclosure. Please
referto the photo below.

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Charge Battery The batteryinnewoscilloscope isusuallydepleted orhasonly
weakpower.Itisnecessarytohaveit charged beforefirsttime
use. Tochargethe batteryyou need toconnectthe device toa
USBpowerwiththe providedUSBcable.Beforeconnecting
USBcableremembertoclosethe batteryswitch asstateabove.
ALEDon PCB boardwilllightup when chargeisundergoing
(photobelow). TheLEDcanbe seenfromoutside ofenclosure.
Aftercharge iscompleted the LEDwillturn off.
AutoPower-off To avoid wasteofbatterypowerDSO112Aiswithautomatic
shut-down feature. When the unitisrunningon battery and
there isno touch activitydetected fora certainperiod oftime
the oscilloscope will shutsdown itself.Thisauto-power-off
time issetto 2minutes bydefault.You maylike to change it to
longerto avoid un-wanted quickshutdown. Please see
description of “ChangeAuto-offTime”section.
Paneland Connectors
Main Working Screen
Thedrawingbelowexplainsthemajordisplayelementsofthe
main workingscreen.

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Mostelementsareself-explainedinthefigure. The following
are some furtherexplanationsforsome elements.
VerticalPosition Indicator
Indicatingthe0Vsignallevel.
HorizontalPosition Indicator
Thisconsistsofagreen bracketand awhiterectangleinside
thebracket.The green bracketrepresentscapturebuffersize
and the whilerectanglerepresentstheviewed portion of
capturebuffer.
TriggerLevelIndicator
Indicatingtriggerlevelwith reference tosignallevel.
TriggerPosition Indicator
Indicating triggerposition inside capturebufferwhich is
represented bythe green brackets.
Connectors Thefollowing figureshowsthe functionsandtypesofDSO112A
connectors.Pleasenotethatthe TestSignalOutputconnectoris
dualfunctional.Itbecomesexternaltriggerinputwhenexternal
triggerisselected. The testsignaloutputisdisabledaccordingly.
Testsignaloutputwill restore when externaltriggerisdeselected.
MaximumVoltage Range
The maximuminputsignalvoltage is50Vpk.
The maximumexternaltriggervoltage is15Vpk.

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Power Button The PowerButton ismulti-functional.
ØWhen oscilloscope isoff short press ofpowerbutton will
turnthe device on if batteryorUSBpowerhasbeen
connected.
ØUnderanystatepress andholdthisbutton for3seconds
will bring up power-off dialog box, inwhich you can select
to poweroff ornot.
ØAtthe power-up screen wherefirmwareversionsareshown
press thisbutton willmake the device enter Setup State
whereFactoryDefault Restore and TouchPanelCalibration
can be performed.
ØUnderanystateholding downpowerbutton formorethat
15 secondswill force the oscilloscope shutdown.
BasicOperations
Power On/Off To PowerOn
Pressthe PowerButton when batteryorUSBpowerhas
been connected.
To PowerOff
DSO112Acan be powered offin three ways:
ØInthe mainworkingscreentouch the “Menu”button at
top-left cornerand select “PwrOff”button.
ØUnderanystatepress and holdpowerbuttonfor3
secondstobring uppower-off dialog box. Then choose
“Yes”orholdthe powerbutton againfor3seconds.The
laterisusefulwhen touch panelisnotworking.
ØUnderanystatecontinuouslyholdthe powerbutton for
15 secondswillforcethe device poweroff.
Probea Signal Once theoscilloscopeentersnormalworkingstatewherethe
main workingscreen isshown you are readyto probe signals.
Toprobe asignalplugone oftheMCX-Clipprobe tothe signal
inputconnector.Connectthe blackcliptothereference point
(usuallycalled GROUND)ofthe circuityou wanttoprobe.
Connectthe red cliptothe signalofinterest.

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State Navigation The followingdiagramshowsthe relationship ofmajorworking
states.
Tip: DSO112AusesresistiveLCDpanel.Itwill havebetter
effectstooperatewithfingernail instead offingerbelly
asinoperatinga cellularphone.
Booting Sequence When powerbuttonispressed theoscilloscope ispowered up.
The maincontroller(MCU)will firstenterthe Bootloader,
whereitwaitsabout2secondsforpossiblefirmwareupgrade
requestfromserial(USB)port.Ifsuch requestisreceived
MCU willstayinBootloadertoperformfirmwareupgrade. If
no requestisreceived the MCU willbootintothe main
firmware ofthe oscilloscope.
Themainfirmwarewillfirstdisplaythestart-up screen at
which informationaboutfirmwareandmanufacturerisshown.
Thisscreen willstayforabout2seconds.Duringthistimeif
the powerbutton ispressed theunitwillenterSetup State,
whereyou canchoosetodo factorydefaultrestoreortouch
panelcalibration. Ifpowerbutton hasnotbeen pressed during
thattimeMCU willthendisplaythe dashboard,atwhichuser
can quicklyputthe oscilloscope intopre-saved setup. The
dashboardwillstayforabout8seconds.Afterthatthe
oscilloscope will enternormalstatewiththe mainworking
screen displayed. You can start normaluseofthe oscilloscope
now.

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Adjust Sensitivity and
Couple Toadjustsensitivityorcoupletouch the lower-left cornerof
screen wherecurrentsensitivityand couplesettingsareshown.
Thiswillbringup “SelectSensitivityandCouple”screen.
Touchthesensitivityand couplesettingsyou wantand then
touch the “Done”button. The newselectionswill takeeffect
immediatelyand oscilloscope isbacktonormalworkingstate.
Ifthe sensitivitysettingyou needisnotdisplayed use “<<”and
“>>”buttonsto navigate.
Adjust Timebase Toadjusttimebasetouch the areawherecurrenttimebaseis
displayed. Thiswillbringup “SelectTimebase”screen. Select
the timebaseyou wantandtouch “Done”button togobackto
normalworkingstate.Thenewtimebasesettingwilltakeeffect
immediately.Ifthe timebasesettingyou need isnotdisplayed
use “<<”and “>>”buttonsto navigate.
Setup Trigger Tosetup triggertouch the area wherecurrenttriggermode and
triggerslope settingsareshown. Thiswillbringup “Select
Triggermode, slope, pos,and src”screen. Selectthesettings
you need bytouchingthe correspondingbuttons. Touch “Done”
button tofinish. Newsettingswill takeeffectimmediatelyand
the scope isbackto normalworkingstate.
TriggerModes
ØAUTO Underthismode the oscilloscope willperform
capturingregardlesstriggerisvalidornot.Whentriggeris
validthewaveformdisplay will synchronizetotriggerand
be stable. Whentriggerisnotvalidtheoscilloscopewill
displaycapturedwaveformrandomlyand waveformdisplay
maybe unstable. Underthismode you will alwaysbeable
to see displayrefreshesregardlesstrigger.
ØNORM Thisiscalled NORMALmode. Underthismode
the oscilloscopewill performcaptureand updatedisplay
when and onlywhen triggerisvalid. Asresult,the
waveformdisplaywillappearfrozen if no triggerisvalid.
You needtoadjustsignaloroscilloscope parametersto
maketriggerhappen inordertosee waveformrefresh.This
mode isusefulforcapturingsparsesignals.Thetemporary
frozen effectmakessparsewaveformstayon screen instead
ofjustflashacross.

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ØSING ThisiscalledSINGLE mode. Itworksverymuch the
sameasNORMALmode. Theonlydifferentisthatonce a
validtriggerisdetectedtheoscilloscopeperformscapture
and updatesdisplay.Itthen enters HOLDstateand stops
furthercapture.ItwillstayinHOLDstateuntilbereleased
manually.Thismode isusuallyused tocapturenon-repeat
signals.
Note:Triggerisignored when timebaseissetto 5us/Div or
faster.ThisisbecauseMCUistoo busyto handle
triggeratthesetimebase settings.
TriggerSlope
Triggerslope isthesignalslope thatischosen tocomparewith
triggerlevel.When the selected signalslopeintersectswith
triggerlevelavalidtriggerisdetected. Themomentwhen the
intersection happensisused asreference pointforwaveform
display.
Triggerslope can be selected asrising, wheresignalisfromlow
tohigh(alsoknownasPositive),orfalling,wheresignalis
fromhigh to low(also known asNegative).
TriggerPosition
Triggerposition isareference pointincapturebufferthatyou
choosetoalignitwithtriggermoments.Iftriggerpositionis
selected toclosethestartofcapturebufferyou willsee more
waveformaftertrigger. Viceversa,you willseemore waveform
beforetrigger.ForDSO112Atriggerpositioncan be chosen to
1/8, 1/4, 1/2, 3/4, or7/8 ofcapturebuffer.
TriggerSource
Triggersource isthe signalthatischosen tocomparewith
triggerlevel.ForDSO112Atriggersourcecan be internal,i.e.
the signalfromscope inputconnector,orexternal,which is
signalfromthe testsignalconnector.

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ExternalTrigger Externaltriggermeansusing adifferentsignalastriggersignal.
Itisusefulinsituationswhereyou wantoscilloscopecaptures
be synchronized byaspecificsignal.Touseexternaltrigger
you need feedthe synchronoussignalintothetestsignal
connectorofDSO112Aandselect “Ext”attriggersetup screen.
Pleasenotethatthemaximumallowedvoltageforexternal
triggersignalis0 –15V.
Trigger Level TriggerlevelisaDC levelthatisused tocomparewithtrigger
signaltodetectintersections.Itisindicated byapinktriangle at
screen rightborder.Triggerlevelcan beadjusted bytouching
anywhereintherighthalf screenand scrollvertically.To
producevalidtriggerthelevelneedstofallinsidethe range
between maximumand minimumsignalamplitude.
Adjust Vertical
Position Toadjustverticalpositiontouch anywhereintheleft half
screen and scrollvertically.
Adjust Horizontal
Position Toadjusthorizontalpositiontouch anywhereofthe screenand
scroll horizontally.
Hold State Capturecanbe temporarilystoppedbyputtingitinHOLD
state. OnceinHOLDstatethe screenrefreshwill bestopped
and the lastcaptured waveformwill remainon displaywhich
can be viewwithoutrush.
ToenterHOLDstate(i.e. frozen awaveform)touch the
top-rightcornerofscreen whereagreen “Running”isshown.
Alternatively,pressthe powerbutton will alsoenterHOLD
state. InHOLDstatethegreen “Running”willturnintoared
“Stop”.
ToexitHOLDstatetouchthetop-rightcorner(orpress power
button)again.
When triggermode issettoSINGHOLDstatewill beentered
automaticallyif validtriggerisdetected.
SelectRecord Length ForDSO112Arecordlengthcan be setto512 or1024points.
Tochangerecordlengthenter “SelectTimebase”screenas
stated in “AdjustTimebase”section and use “>>”button to
navigatetotheendpage.Selectwanted recordlengthand touch
“Done”to finish.
Test SignalOutput ThetestsignalofDSO112Aisforprobecheckingand
calibrationpurpose.Itisnotageneralsignalsource. The
nominalamplitude ofthe testsignalis3.3Vwith5%tolerance.
Theoutputimpedanceis1Kohm.Testsignalfrequencycan
selected fromseveralpresetvalues(see instructionsbelow).
Once externaltriggerisselected thetestsignaloutputwillbe
disabled automatically.Itrestoresassoon asinternaltriggeris
chosen.

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AdvancedOperations
VPosAlignment Sometimesthe verticalposition indicatoratscreen leftborderis
notaligned with0Vleveltrace. Thiscan be fixedby
performingVPosAlignment.Todo thistouch “Menu”at
top-left screen cornertobringup menu pageand selectthe
button “VPosCal”.
Save Waveform Captured waveformcan besaved toin-chipEEPROMsoasit
isretained afterpowerdownand can be recalled atalatertime
forreviewing.Todo thisenterMenu and touch the button
“SaveWF”.The mostrecentlycaptured anddisplayed
waveformbeforeenteringMenu willbe saved. Theassociated
scope parameters arealso saved atthe same time.
Inordertomakesurethe rightwaveformissaved it is
suggested to holda waveformbeforesavingit.
Pleasenotethatsavingawaveformwill overwritethe data
alreadyinEEPROMwithoutwarning.Thatistosay,the
previouslysaved waveformwill be lostwhen anewwaveform
issaved.
Recall Waveform Saved waveformcan berecalled and displayed on screen
withoutanychange. Todo thisenterMenu and touchthe button
“Recall WF”.Recalled waveformisalwaysdisplayed inHOLD
state.

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Send WaveformData Waveformdatacan betransferred throughthe serialport toa
differentdevice (usuallyaPC)asCSVfileforstorageor
furtherprocessing. In orderto complete the transferyou need:
ØAcorrectlysetup serialconnection, and
ØApieceofcommunicationsoftwarethatrunsonPC
and supportsXModemprotocol.We will useTeraTerm
hereasdemonstration.
Thesearethe stepsto performwaveformdata transfer.
Setup SerialConnections
1) ConnectDSO112Aoscilloscope to an USBporton PC.
2) DSO112AcontainsaUart-USBbridgeCP2102.You need
installdriveron the PCforthischipif you arethe first
timeusingthePCforDSO112A.PleasegotoSilicone
Lab website www.silabs.com todownload the appropriate
driverforyoursystemand install itcorrectly.
3) Install communication software. Here we useTeraTermas
example. TeraTermisforWindowsonly. ForotherOS
you need toinstall similarsoftware. TeraTermcan be
downloaded at
http://www.jyetech.com/Support/Drivers&Tools.php.
4) Setup communication software. Start TeraTerm. Click on
the menu “Setup ->Serialport”tobring up serialport setup
window(see figuresbelow).

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SelecttheportthatiscorrespondingtoDSO112A(you can
identifyit bygoingtoWindowshardwaremanagerand
connecting/disconnectingthe USBcable).Setparameters
asshowninthe figureabove.
5) Preparedatatobetransferred. Capturethewaveformyou
need andputDSO112AinHOLDstatesothatthe
captured datawill notchange. Ifwaveformhasbeen
pre-saved toEEPROMuserecall function tobringit to
screen. Pleasenotethatonlythewaveformthatis
displayed before enteringMenu istransferred.
6) Starttransfer.Tostart transferenterMenu and touchthe
“Send Data”button. DSO112Awillentersendingstate
waitingforrequestfromPC.Thiswaitingperiod isabout
45 seconds.AtTeraTerm select “File->Transfer->
XMODEM->Receiver”(see figurebelow).Thiswill
open adialogthatallowsyou toselectfilenameand folder
forthecomingindata. Remembertonamethefilewith
“CSV”extension. Ifyou forgettodo soatthismoment
you can renameit aftertransferisfinished. Selectthe
option “Checksum”or “CRC”atbottomand keep
“Binary”checked. Clickthe “Open”button. Ifconnection
isgood you should see transferfinishesinseconds.

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7) Verify.Gotothefolderwherereceived filewasstoredand
open itwith Excelora textreader.
Forthe formatofwaveformdatafilepleaseseedetailed
description inSection 5 later.

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Restore Factory
Default Torestorefactorydefault settingsenterMenu and touch the
button “Default”.Alternatively,you can doforcedfactory
defaultrestoreatpower-up byenteringSetup state.Pleasesee
the subsection “BootingSequence”in Basic Operations.
Factorydefaultsettingvalues
Parameter FactoryDefaultValue
Sensitivity 0.5V/Div
Couple DC
Vertical Position 0
Horizontal Position 80
Timebase 1ms/Div
Trigger Mode Auto
Trigger Slope Falling
Trigger Position 1/2
Trigger Level 0V
Trigger Source Internal
Record Length 512 points
VPosCorrection 0
Measurements All off
TestSignal Frequency 1KHz
AutoPower-off Time 2minutes
Save/Recall Presets Presetsaregroupsofoscilloscopesettingsthatarepre-saved in
EEPROM.Thesesettingscan be recalled toreplace existing
settingstosavesetup time. Upto24 presetscanbe saved. This
isveryusefulforfrequentlyperformed measurements.
TosaveorrecallapresetenterMenu andtouch the “Preset”
button. Thepresetscreenshows(seefigurebelow).Each row
representsamemorylocation. Thereare24 locationsavailable
infourpages.Use “<<”and “>>”buttonstonavigatethrough
the pages.When alocationcontainspresetthesummaryofthe
presetisdisplayed. An emptylocationisindicated with “---“.
Touch arowtoselectthe location whereyou wantpresetsbe
saved toorrecalledfrom.Theselectedrowwillbehighlighted.
Touch “Save”button tosavecurrentoscilloscope settingstothe
location. Pleasenotethatthe previouslysaved settingsinthe
selected location willbe overwritten withoutwarning.Touch
“Load”button torecallthesettingsthathavebeenpreviously
saved inthe selected location. Therecalledsettingswill take

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placeofcurrentsettingsand takeeffectimmediately.Ifthe
selected location isemptythe recallrequestwillbe ignored.
Rename Presets The titlesofpresetscan be renamed foreasyrememberand
identifying.Todo thisselectapresetand touch the button
“Rename”attop ofscreen. Thecharacterkeypad willshow(see
below).Type inpresetnameand finishwiththe “Done”button.
Maximumtitlestringsizeis8characters.Use “BS”(Back
Space)button tocorrecterrors.
Enter Dashboard Touchthebutton “DashBrd”tobringup dashboard. Thisisan
alternative wayforquickpresetaccess.
SelectTest Signal
Frequency Bydefaultthetestsignalis1KHzsquaresignalwith3.3V
amplitude and 50%dutycycle. Thefrequencycan be selected
tobe afewpre-setvaluesincluding1Hz,10Hz,100Hz,1KHz,
10KHz,100KHz,1MHz, and440Hz.Toselectdifferent
frequencyenterMenuandtouch the “TestSig.”button. The
TestSignalFrequencyscreen shows.Selectthefrequency
wanted and touch “Done”button tofinish.

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TCursors Tcursorscan beturnedonoroffbyenteringMenu and touch
the button “T”.When thecursors areon thetimedifference
betweenthetwocursorsisdisplayed atthescreentop-left
corner.Thisreadoutchangesascursorposition changes.
Tochangecursorpositionfirstselectthe cursoryou wantto
movebytouchingit soasit ishighlighted. Then touch any
whereinscreen andscrollhorizontally.You shouldsee the
selected cursorshifts.De-selectthe cursorbytouching it again
orbyselectingthe othercursor.
Pleasenotethatthe unit for Treadoutisthe sameasthatof
currenttimebase.
VCursors Vcursorscan be turnedon oroffbyenteringMenuand
touchthebutton “V”.Whenthecursorsareonthe voltage
difference between the twocursorsisdisplayed atthe screen
top-left corner.Thisreadoutchangesascursorposition
changes.
Tochangecursorpositionfirstselectthe cursoryou wantto
movebytouchingit soasit ishighlighted. Then touch any
whereinscreenand scroll vertically.You shouldsee the
selected cursorshifts.De-selectthe cursorbytouching it again
orbyselectingthe othercursor.
Pleasenotethattheunitfor Vreadoutisthesameasthatof
currentsensitivity.
Frequency
Measurement Frequencymeasurementcan beturnedon oroffbyentering
Menu and touch the button “Freq”.Frequencyreadoutis
displayed atthescreen lower-rightcorner.Pleasenotethat
frequencymeasurementisdisabled whentimebaseissetto
50ms/Divorslowerbecauseitwillcausewaveformsampling
errordue tolimited MCU capability.
Voltage
Measurements Voltagemeasurementscanbe turned onoroffby entering
Menu and touch the button “V”.Voltagemeasurementsinclude
Vmax, Vmin, Vpp, Vavr,and Vrms(trueRMS)ofcaptured
waveform.The readoutsaredisplayed atthescreen lower-left
corner.Pleasenotethatvoltagemeasurementsaredisabled
when timebaseissetto50ms/Divorslowerbecauseit will
causewaveformsamplingerrordue tolimitedMCU capability.
Change Auto-offTime
Tochangeautopower-offtimeenterMenu and touch
“More>>”atscreen top-rightcornerand thentouchthe button
“AutoOff”.Thisbringsupthe “AutoPower-offTime”screen.
Autopower-offtimecan be setto2, 5, 15, 30, 60 minutesor
Never.Ifthereisnoscreentouch activitydetected withinthe
timeperiodtheoscilloscopewill shutdownitself.However,if
externalpowersupply(USB)isused the autopower-offtiming
isdisabled.The unit willnevershutdown itself inthiscase.

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SerialInterface (SI)
Introduction TheSerialInterface (SI)ofDSO112Aisaserialconnection that
can outputcaptured data/waveformmeasurementsand take
commandsto operate the oscilloscope remotely. The connection
can be avirtualCOMporton USBorLVTTLUarttoanother
controller.ForthelatterpleaserefertotheSection “Useasan
Integration Module”formore details.
The bitstreamformatforthe SIis 115200 baudrate, 8data
bits,1stop bit,and no parity.Thisisfixedand cannotbe
changed.
TheUSBconnection isbased on aCP2102 Uart-USBbridge
inside DSO112A.You needinstalldriverforthisbridgeon PC
if itisthe first timetoconnecttoDSO112A.Pleasegoto
SiliconeLab websitetodownload the appropriatedriverfor
yoursystemand install it correctly.The web page linkis:
http://www.silabs.com/products/mcu/pages/usbtouartbridgevcp
drivers.aspx
Datatransferred throughthe SIareinframes.Allframesare
withthe generalformatgiven inthe tablebelow.
Thisformatobservesthree rules.
1) FrameIDmustnotbesame asthe Sync character(0xFE).
2) Ifabytehasthe value of0xFEa0x00 bytemustbe
inserted rightafterit in transmission.
3) All multi-bytedatafieldsaretransferredinlittleendian
orderunlessotherwisestated.
OffsetField Name Size Value
-1 Sync character 1 0xFE
0 FrameID 1
1 Frame Size 2
3 Payload startsVariable

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OutputofCaptured
Data DSO112Ahastwoworkingmodes.Normallyit worksin
StandaloneMode wherecaptured dataaredisplayed on LCD
panelaswaveform.Insituation wherecaptured dataarewanted
DSO112Acanbeset USBScope Mode. UnderUSBScope
mode waveformdisplayon panelwillbe disabled. All captured
dataareoutputthrough the SI.
Tomakethe oscilloscope enterorexitUSBScope mode certain
commandsarerequired. Thesecommandsmustbe senttothe
oscilloscope viatheSI.Allavailablecommandsaredescribed
in detailsinthe section “Commandsand Their Returns”below.
InUSBScope mode the oscilloscopepanelwilllooklikethe
photobelow.Touch the “Exit”button toreturntostandalone
mode.
When timebaseissetto20ms/divorfastertheoscilloscope will
outputcaptured datainblocksofsamples.Each blockcontains
the wholebufferofdata. The formatofoutputisshowninthe
table below.
Becauserecordlengthcan havedifferentvaluesthe framesize
isvariable.
When timebaseissettoslowerthan 20ms/dic(i.e. 50ms/divor
slower) oscilloscopewill outputdatainsinglesample. Each
frame containsonlyone sample. The formatisshownbelow.
OffsetField Name Size Value
-1 Sync character 1 0xFE
0 FrameID 1 0xC0
1 Frame Size 2 Recordlength+ 8
3 DataType 1 0x32
4 Captured dataRecord
length Each bytefor one sample
RL+ 4 Reserved 4
OffsetField Name Size Value
-1 Sync character 1 0xFE
0 FrameID 1 0xC0
1 Frame Size 2 8
3 DataType 1 0x33
4 One sample 1
5 Reserved 3

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Outputof
Measurements Measurementsinclude thevoltages(includingVmax, Vmin,
Vpp, Vavr,Vrms) andfrequencyofcapturedsignal.
Measurementoutputfromthe SIcan be enabled ordisabledby
aspecificcommand. Thiscommand isdescribed indetailsin
the section “CommandsandTheir Returns”below.
Measurementoutputframe iswiththe followingformat.
All voltagesare expressed in 16-bit signed integer. Frequencyis
expressed in32-bit unsigned integer.
HowtoDetermine True Voltage
Pleasenotethatthebyteatoffset4iscalled “VoltageBaseUnit
(VBU)”.ItisaconstantnumberinunitofuVand thevalue is
20, representing20uV.The half-wordatoffset6iscalled
VoltageResolution (VR),representingvoltageperLSBinthe
voltagemeasurements.Thevalue ofvoltageresolutiondepends
on sensitivitythatwasused tocapturethe data.Tocalculate
truevoltage the followingformula can be used:
V= Measurement* VR* 20 (uV)
Forexample, when sensitivityissetto2mV/Divthe
correspondingVRis4. IfVmax =100 thismeanstrue
maximumvoltage is
100 * 4 * 20 = 8000 (uV)=8mV
Ifsensitivityisset0.5V/Divthe correspondingVRis1000. The
samemeasurementvalue (i.e. 100)represents
100 * 1000* 20 = 2000000(uV)= 2V
OffsetField Name Size Value
-1 Sync character 1 0xFE
0 FrameID 1 0xC0
1 Frame Size 2 0x1E(30)
3 Datatype 1 0x34
4 Voltage base
unit (VBU)in
uV
1 0x14 (20 )
5 Reserved 1 0x00
6 Voltage
resolution in
VBU
2 Sensitivity
dependant
8 Vmax 2
10 Vmin 2
12 Vpp 2
14 Vavr 2
16 Vrms 2
18 Reserved 2
20 Frequency 4
24 Reserved 6