you often need in MCU debug-ging. On the other hand, logic ana-lyzers can handle these newerchips, of course, but they can’talways handle the analog signalsand they usually offer more powerthan you really need for mostC500/166–based designs.

The best of both worldsA new type of instrument, themixed signal oscilloscope (MSO),closes the gap in MCU debuggingtools. The HP 54645D fromHewlett-Packard (see inside backcover) combines two analogscope channels with 16 digital log-ic channels, so you can monitoranalog and digital lines at thesame time. This MSO offers morepowerful triggering than a scope,including the ability to define pat-tern triggers across both analogand digital lines. Of course, youcan also trigger it from your emu-lator if you need to synchronizecode and signal analysis. Deepmemory is another key feature inthis new instrument, giving youup to a million samples on eachchannel.

Digital signals from an analog perspectiveAs MCU clock speeds increase,the analog nature of your digitalsignals becomes increasinglyimportant. Is the output thresholdof the serial interface or the CANbus high enough? Is the timing ofthe digital outputs correct? TheMSO delivers reliable answers tothese and many other questions,including such problems as elec-tromagnetic radiation, capacitiveloading and power supply faults.

Whether you use an MSO by itselfor in conjunction with an emula-tor, you’ll find it offers a newdimension of MCU debuggingpower.

Filling the gap in MCU debugging tools

Klaus Hommann

Klaus Hommann is a technical

consultant and sales advisor for

Willert Software Tools, a supplier

of Siemens MCU development

tools in Bueckeburg, Germany.

The steadily decreasing size andsteadily increasing speed andcapability of advanced microcon-trollers, such as the SiemensC500/166 family of MCUs, givedesigners some impressiveoptions for designing new prod-ucts. On the downside, these newMCUs also give designers someadvanced headaches during test-ing and system integration.

Traditional tools aren’t always up to the taskTo complicate matters, the debug-ging tools most designers have attheir disposal aren’t providingenough support. Emulators andROM monitors won’t work unlessthe MCU is up and running, sothey’re not much help if you’restruggling with power lines, clocksignals, drivers, missing pull-upresistors and other common prototype problems.

And even when you can operatethem, emulators and ROM moni-tors can’t address many MCUdebugging problems, includinginterference between analog anddigital signal lines on the printedcircuit board and on most any-thing involving analog I/O signals.

Many engineers have relied onoscilloscopes for debugging MCU-based designs, but the move from4-bit to 8- and 16-bit MCUs is leav-ing scopes behind. Plus, scopescan’t offer the complex triggering

Introduction

ContentsHint 1: Verifying PWM dead time inmotor controllers. Using mixed analogand digital channels to verify proper sig-nal timing in a Siemens C504-based sys-tem. Technical Staff, Microcontroller Group,Siemens Semiconductor

Hint 2: Debugging external interruptsin Siemens C500 MCUs. Capturing atroublesome scenario in which the LCALLinstruction gets blocked, effectively dis-abling external interrupts. David Bordui,QXI

Hint 3: Testing a C167–based PWM solenoid circuit. Analyzing and debug-ging the closely coupled analog and digi-tal signals in a solenoid control circuit.Mark Fabiny, Siemens Microelectronics

Hint 4: Evaluating high-precision ser-vo drives. Using mixed-signal measure-ments to help synchronize comparators,ADCs and other components. Frank Stolleand Jörg Droßmann, SICAN Braunschweig

Hint 5: Using deep memory to mea-sure transceiver disable time. Using manualtriggering techniques to capture longdata streams for post-measurementinvestigation. Patrick Pettibon, SiemensMicroelectronics

Hint 6: Verifying A/D conversion in a C164 single-chip system. Linking anMSO with an emulator to correlate pro-gram execution with hardware operation.Thomas Hammerschmidt and WolfgangSchmitt, Hitex Development Tools

Hint 7: Using propagation delay tomeasure CAN cable lengths. Using anMSO to make sure CAN cable lengths arewithin acceptable operating limits. IngoPohle and Renate Schultes, MicroConsult

Hint 8: Accessing fine-pitch I/O pinson Siemens MCUs. Taking advantageof the new HP Wedge to gain secure,nondestructive access to the 0.5- and0.65-mm pins on high-density packages.Johnnie Hancock, Hewlett-Packard

a better choice because you canmeasure multiple analog and digi-tal waveforms simultaneously andset up complex logic triggers.

Figure 2 verifies that the pro-grammed dead time is sufficientfor safe PWM switching. Thiszoomed-in display shows the

HINT

1Verifying PWM dead time in motor controllersTechnical staff, Microcontroller Group, Siemens Semiconductors www.sci.siemens.com

Generating pulse width modulated(PWM) signals with an MCU is a common way to control ACmotors with sine-wave shaped currents. A typical application for an 8-bit MCU is controlling athree-phase induction drive withvariable speed in an open-loopconfiguration.

However, the MCU can’t drive aninduction motor directly, so youneed to amplify the three-phasesignals first. Instead of using ana-log amplifiers, a more efficientway is to digitally amplify thePWM outputs with power switch-es, such as MOSFETs or IGBTs.The three-phase inverter shown in Figure 1 accomplishes this function.

The hardware for each phase ofthe inverter consists of two powerswitches (high side and low side)in a push-pull configuration. Thiscreates a potential problem,though, if the control signals forthe switches are exact comple-ments of each other. During PWMswitching, both power switchesmight momentarily conduct simul-taneously due to different transis-tor turn-on and turn-off latencies.This can create a high-currentshort circuit and may destroy theinverter. It’s therefore importantto use an MCU optimized formotor control, such as theSiemens C504 (an 8051 derivative)or C164 (16-bit architecture). Bothcan be programmed to insert“dead time” in the PWM outputsby hardware without any softwareoverhead. The dead time ensuresthat the two switches never con-duct at the same time.

After programming the microcon-troller to create the PWM outputsignals with dead time, the nextstep is testing the wave shape andtiming. A four-channel scope cando the basic measurement, but ifone is available, a mixed signalscope such as the HP 54645D is

SiemensC504MCU

HP 54645DMixed signaloscilloscope

Three-phaseinverter

Userinterface

(PC)

Three-phasemotor

Threephases

PWMsignals

Asynchronousserial link

Figure 1: Block diagram of

an open-loop configuration

for generating safe PWM

signals to drive a three-

phase motor.

impact of the dead timeon the analog gate-source voltage of thepower switch MOSFETs.The scope’s cursors sim-plify the correct timingmeasurement and helpcharacterize the circuitprecisely.

With combined digital and analog measure-ment channels, you caneasily monitor all sixPWM signals and thephase currents. Figure 3shows the two phasecurrents and corre-sponding digital PWMpattern. The time-quali-fied trigger mode letsyou synchronize thescope’s display to anadjustable pulse widthcorresponding to a well-defined phase angle.

Figure 3: Monitoring all six PWM signals and the phase

currents on the high-side and low-side switches.

Figure 2: Verifying the dead time between the high-side and

low-side PWM outputs.

FET switches off

FET switches on

The potential for trouble existswhenever the MCU is set to edge-sensitive interrupt mode and the

peripheral requires theMCU to reset its inter-rupt line. Commonculprits include multi-channel USARTdevices that randomlyinterrupt the MCUupon reception of seri-al data from a periph-eral. The MCU canmiss the interrupt edgeand therefore fail toreset the interrupt line.Once this happens, theperipheral appears tobe locked up.

The trouble starts when the LCALLinstruction gets blocked, whichcan happen in several different sit-uations with C500 devices (two ofwhich are particularly hard to diag-nose because all the relevant actionhappens inside the CPU core).

A close look at the CPU timing dia-grams in the C5xx databook helpsexplain the problem. C5xx devicesdivide the external oscillator by 12to form a single instruction cycle,and each cycle is divided into 6

Figure 1: The CPU timing diagram

shows why LCALL gets blocked after the

RETI command is generated.

Figure 2: In this HP 54645D screen shot,

a closer inspection of the external interrupt

edge (analog line A2) relative to the RETI

fetch (digital lines 0-7) and oscillator

segment and phase reveals the offending

condition.

Cycle 2 Cycle 3 Cycle 4S6S5P2

Cycle 1 Interrupts polled LCALL generated

Interrupts latched

INT×

XTAL1

PSENALE

Data bus

Trigger point:ALE=HighXTAL1=HighD7-D0=32hex (LLHH LLHL)INT×= (falling edge)

David Bordui a Field Applica-

tion Engineer with QXI, a Siemens

representative in Longwood,

Florida, USA.

Is a peripheral in your systemscreaming for attention? Under cer-tain conditions, the Siemens C500and derivatives (as well as other8051-based microcontrollers fromother manufacturers) can missinterrupt requests from peripherals.

segments (S1-S6) with 2 phases ofthe oscillator in each (P1 and P2).An address latch enable (ALE)always occurs on the S1P2..S2P1and S4P2..S5P1 time intervals, andALE transitions indicate a fetch ofthe next opcode. The interruptreset instruction RETI is a 1-byte,2-cycle instruction, which meansthe next three opcodes are discard-ed while the interrupts remainlatched (Figure 1).

To isolate this problem, I connect-ed digital channels from an HP 54645D mixed signal oscillo-scope (MSO) to ALE, PSEN anddata lines D0-D7. To avoid exces-sive loading on the oscillator, Iused the two analog high-imped-ance channels to capture and dis-play the oscillator (XTAL1) and theexternal interrupt signal (INTx).

The MSO’s pattern trigger made iteasy to capture the problem sce-nario by watching for a “high” onALE, an 0X32HEX (RETI instruc-tion) on the data bus, a “high” onthe oscillator input, and an activefalling edge on INTx. This makes itsimple: if the scope triggers, theproblem is there (Figure 2).

Switching to level-sensitive inter-rupts will avoid the problem when-ever that's an option. When it isn’t,a simple hardware fix will do thetrick. Connect the ALE line (orPSEN) to one input of an OR gateand the interrupt output from theexternal USART to the other input,then connect the OR output toINT×. The USART’s interrupt linewill gate the pulsing ALE line,thereby creating multiple edges forthe MCU. (For rising edge inter-rupts, use an AND gate.)

Of course, it’s always a good ideato use software checks to makesure each interrupt event is ser-viced only once, and it's particular-ly important in this case sinceyou’re generating multiple inter-rupt signals.

Debugging external interrupts in Siemens C500 MCUsBy David Bordui www.qxi.com

HINT

2

Figure 2: Four key signals

from Figure 1. SOLEN is an

analog signal from the low

side of the solenoid; the zener

diode clamps inductive

spikes at 40 V. SENSE, mea-

sured across a 0.1Ω resistor,

peaks around 380 mV, which

corresponds to 3.8 A PWM

drives the power transistor.

The initial 300 µs pulse is the

time required to achieve peak

current. COMPAR triggers at

380 mV across the sense

resistor and is fed into cap-

com channel 8 to signal the

MCU to enter hold mode until

the solenoid is turned off.

Testing a C167–based PWM solenoid circuitBy Mark Fabiny www.sci.siemens.com

driver to modify the holding cur-rent. Also, the MSO’s 16 digitalchannels make it possible to viewall 16 solenoids at once—-particu-larly useful when integrating theentire system because the sole-noids are actuated in specificsequences that must be verified.

Mark Fabiny is a Microcontroller

Applications Specialist for

Siemens Microelectronics in

Dallas, Texas, USA.

Microcontrollers provide a level ofprogrammability and functionalitythat makes them a viable alterna-tive to application-specific semi-conductors such as pulse widthmodulation controllers. However,this increased capability can pre-sent new challenges for testingand integrating new designs.

The example presented herecomes from a customer’s need todrive sixteen solenoids in a med-ical analyzer. Previous designsused three complex programma-ble logic devices driving discretepower drivers in saturation mode.The new design required that thesolenoids also be driven with a“peak-and-hold” driver to limitcurrent draw and to prevent damage if a low-impedance solenoid is accidentally installed.

The customer investigated variousPWM controllers and drivers butthis approach did not satisfy thecost or functionality requirements.We proposed a new design basedon an MCU. As shown in Figure 1,the SABC167SR MCU has 32 cap-ture/compare (capcom) channelsand 16 analog inputs. The func-tionality and I/O capabilities of theC167 let the customer use just oneMCU to drive 16 solenoids whileaccomplishing all of the designgoals.

The HP 54645D mixed signal oscilloscope (MSO) permits simul-taneous analysis and completedebugging of the closely coupledanalog and digital signals in thecircuit (Figure 2). The MSO’s deepmemory captures several cycles ofthe solenoid, which aids in debug-ging the section that uses pulsewidth modulation of the power

Figure 1: The capcom channels

are individually programmed

for “input capture” and “output

compare” functions, which drive

each solenoid and sense the peak

current threshold, respectively.

Capcom channel 0 drives a pow-

er transistor; the sense resistor

at the emitter leg is for current

monitoring. The op-amp condi-

tions this signal and provides

feedback to Analog Input 0,

which monitors the holding cur-

rent. The comparator signals

when peak current is reached.

HINT

3Currentmonitor

Gain stage

Vtrig

Comparator

5 V

Vcompar 0.1 Ω

Vsolen

40 V Zener

Vsense

Solenoid

12 Vdc

Vpwm

One of 16 solenoid circuitsSiemensSABC167SR

16-bitMCU

Analog input 0

Capcom Ch. 8

Capcom Ch. 0

Filter Op amp

Circuits of this nature can be diffi-cult to examine because the PWMportion requires a time base that ismuch faster (less than 50 µs) thanthe overall solenoid on-time(greater than 1 s). The events sur-rounding the transition from peakmode to hold mode are the mostcritical, and the MSO’s glitch trig-gering is a convenient and reliableway to capture these signals.

Frank Stolle and Jörg Droßmann

are Project Managers with SICAN

Braunschweig GmbH, Braun-

schweig, Germany.

Our servo positioning systems typically use incremental encodersfor precise position control. Theseencoders generate two sine wavesoffset by 90 degrees, then we usecomparators to derive square-shaped position counter signals

Evaluating high-precision servo drivesBy Frank Stolle and Jörg Droßmann www.sican.com

Figure 2: In this HP 54645D

screen shot, signals AD 11

and A1 LAT give conflicting

information about the sam-

pled signal.

Figure 3: The cause uncov-

ered: the sampling edge

occurred immediately

after the zero crossing.

HINT

4Figure 1: Block diagram

of a high-precision posi-

tion controller.

from the sine waves. Every squarewave edge increments or decre-ments a position counter, with rota-tion direction indicated by the edgedirection and the level of theencoder signals. For maximum pre-cision, we also sample and digitizethe sine waves.

Figure 1 shows a servo system thatincludes a Siemens C167CR MCUand a digital Smart Motion

Controller (dSMC) from SICAN.The C167CR manages communica-tion interfaces and high-level con-trol tasks. The dSMC contains aPWM unit, a position counter, ADCinterfaces and an embedded DSPthat performs torque, speed andposition control.

Figure 2 highlights a problem werecently encountered. At the beginning of every control loop, the dSMC (see the SAMPLE sig-nal) latches the position counter values and the encoder signals.Simultaneously, the encoder sinu-soids are sampled. After conversion(11 µs later), the signal AD11 (MSBof the ADC output) goes low, indi-cating that the digitized analog sig-nal had a positive polarity whensampled (SAMPLE). However, thesynchronous comparator output(labeled A1 DIG) remains low, indi-cating a negative polarity.

Figure 3 explains the inconsistency.The sampling edge occurred imme-diately after the rising sine signalcrossed zero. However, the com-parator output (A1 DIG) had not yetchanged, possibly due to hysteresisor a zero offset difference in theADC's level. The dSMC chip cansolve this problem by recognizingsuch inconsistencies and correctingthe reading of the position counter.

Examining behavior such as this isnearly impossible with a conven-tional oscilloscope. The MSO’s deepmemory also let us trigger on theinconsistent ADC result and thenexplore the related signals.

CANinterface

HostC167CR

dSMC101

Inverter

Switchsignals

Errors & protection

Serial link (USCI)

Encodersignals

AC machine

Analog front end

AD [11...0]

A 1_DIG

12

Encoder interface

Track A

Track BA D S&H

A D S&H

®

the transceiver from my PC, thenquickly pressed Run/Stop on thescope. After several tries, I wasable to capture the disable event(Figure 2). At 10 ms/div, I lackedsufficient visual resolution to mea-sure the event, but HP MegaZoomlet me zoom in to 2 µs/div (Figure3), providing more than enoughresolution. In other words, usingmy finger as the trigger source, I was able to capture a transientevent only 2 µs long.

You can capture simi-lar events using othermanual triggers suchas push buttons, seri-al commands ortimer interrupts. WithHP MegaZoom’s onemillion samples andsimple pan andzoom, you just needto trigger somewherenear the signal to see it. Figure 1: Measuring the

transceiver disable time.

Figure 2: The long data

stream captured in

HP MegaZoom memory.

Figure 3: By panning

and zooming, I found the

trigger disable time—an

event only 2 µs long.

HINT

5Patrick Pettibon is a Field

Applications Engineer with

Siemens Microelectronics in

Dallas, Texas, USA.

Even the most powerful scope trig-gering features aren’t much help ifyou can’t access the signals you’dlike to use as trigger events. Ifyou’ve ever probed dense circuitboards or the fine-pitch leads ofsmall but powerful chips such asthe Siemens C166 MCU family, youunderstand the problem.

On a recent project, I encountereda transceiver controlled by a C161 MCU; a PC controlled theentire system through its serialport (Figure 1). I wanted to mea-sure the disable time of the trans-ceiver. Sounds easy enough: justtrigger on the chip select and writestrobe signals to the peripheral.

While my HP 54645D mixed signaloscilloscope (MSO) could certain-ly trigger on such a combination,the software running on the C161was confusing the issue by writingto the peripheral for more thanone purpose. I needed to qualifythe trigger with an address, but Ididn’t have a test clip for theMCU’s tiny MQFP package, leavingme without access to thedata/address bus.

With a firmware change, I could’vefound a way to cycle the trans-ceiver’s state, but the MSO’sMegaZoom feature saved me thetrouble. By entering a disable com-mand on the PC and then pressingthe Run/Stop key on the scope, Iwas able to capture the event man-ually. Even though the interestingpart of the signal lasted only a fewmicroseconds, HP MegaZoom cap-tured enough samples to see theresults in great detail.

I first set the time base to 10 ms/divin order to capture 100 ms of thetransceiver signal. Next, I disabled

Using deep memory to measuretransceiver disable timeBy Patrick Pettibon www.sci.siemens.com

HP 54645DMixed signaloscilloscope

PC to controltarget board

Target boardwith C16 1 MCU

Analogtransceiver

(could be C16peripheral also)

RunDisable thetransceiver

Port

5

A/DPEC

RTC

Port 4

ASCO

Analysissoftware

Protocolsoftware

Internal RAM

SiemensC164C1MCU

Timer

Analogsignals

Controlhardware

PC

Figure 1: Block diagram of the C164CI

automotive application.

HINT

6

Figure 3: Correlation

between analog and

digital channels.

Figure 2: Hitex DProbe167

emulator screen with display

of PEC transfers and register

values.

Thomas Hammerschmidt and

Wolfgang Schmitt are with Hitex

Development Tools in Eching,

Germany.

We recently deployed a SiemensC164CI MCU in an automotiveapplication (Figure 1) to moni-tor and respond to a variety ofoperating parameters, includingpressure, temperature and

Verifying A/D conversion in aC164 single-chip systemBy Thomas Hammerschmidt and Wolfgang Schmitt www.hitex.com

transferred to internal memory via a DMA method known asperipheral event control (PEC).ROM-based analysis softwarewatches for failures and mis-matches among the various signalsand controls the outputs of Port 4depending on the detected failure.Failures are reported to the on-chip RAM along with the real timeclock value and can be monitoredvia a serial link or CAN interface.

During design integration, weneeded to verify system behaviorwhen one of the analog channelsreported a failure, which requiredsimultaneous capture of the pro-gram flow and the external analog(Port 4) and digital (Port 5) signals.

To analyze the program flow, anin-circuit emulator with the abilityto debug and modify ROM codeproved indispensable (Figure 2).The enhanced trace and triggerfunctions, along with integratedperformance analysis, also madethe investigations much easier.

To measure the analog and digitalsignals, we used the HP 54645Dmixed signal oscilloscope (MSO),with the emulator providing a trigger (displayed as TRIGG inFigure 3) for the MSO. In additionto the simultaneous analog anddigital measurements, the MSO’sdeep memory helped us get a complete picture of the overallsystem behavior.

acceleration. Eightanalog signals are con-nected through Port 5to the analog-digitalconverter, which con-verts channels 0-3 con-tinuously (the otherchannels are convert-ed based on timerinputs). The results are

Figure 1: Signal propagation delay (TxD - RxD) through

one transceiver is 174 ns (87 ns in each direction).

Trigger signal

TransceiverSignal converter/amplifier

Optocoupler for isolation(optional)

Test setup: cable length approx. 100 m @ 400 kbits/s

Transceiver

Optocoupler

124 Ω

HP 54645DMixed signaloscilloscope

DigitalA1 A2CAN

End node #2

R D T DR D T D

124 Ω

CANEnd node #1

Continuouslyacknowledges

Continuouslysends frames

Ingo Pohle and Renate Schultes

are with MicroConsult, a training

center for microelectronics and

information technology in

Munich, Germany.

The maximum acceptable length ofan installed CAN cable is limitedby baud rate, propagation delaythrough each component and anyoffset between the oscillators sup-plying the baud rate clock. If youknow the delay through the trans-ceivers and the delay through theentire network, you can derive thedelay through the cable itself andfrom there, the actual cable length.Using an HP 54645D mixed signaloscilloscope (MSO), we first measure the transceiver delay(Figure 1).

Next, we measure the total delayfrom node to node, using a triggersignal from the master (CAN endnode #1) to start data acquisitionon the MSO (Figure 2).

The master starts to transmit aframe immediately after sendingthe trigger signal. Figure 3 showsthe trigger signal (on the MSO’sdigital channel 5) and the T×D andR×D signals on the MSO’s two ana-log channels. Using the MSO’s dis-play cursors, we then measure thelength of the 12-bit interval fromthe beginning of the acknowledgebit to the next following start bit.

At the 400 Kbps baud rate in thissystem, the nominal time intervalis 30 µs (12 bits × 2.5 µs/bit). The

Using propagation delay to measure CAN cable lengthsBy Ingo Pohle and Renate Schultes www.microconsult.com

Figure 2: Test system configura-

tion for cable length measure-

ment; a mixed signal oscilloscope

can measure both the analog and

digital signals in this point-to-

point CAN system. If the CAN

network also includes optocoup-

lers, we need to measure and

account for their delay as well.

Figure 3: The time interval for this 12-bit sequence is

29.1 µs from the acknowledge bit to the next start bit.

HINT

7900 ns difference between the nom-inal value and the measured inter-val shown in Figure 3 (∆ t = 29.1 µs)consists of the transceiver’s signaldelay and the signal propagationdelay along the cable. Knowing this,we can compute the delay throughthe cable:

Tcable = Ttotal – (4 × Ttransceiver)= 900 ns – (4 × 87 ns)= 552 ns

Next, we can compute the actualcable length:

Lcable = Tcable × 0.17 m/ns= 552 ns × 0.17 m/ns= 93.84 m

Knowing the exact length of theinstalled cable, we can confirmproper operation at the operatingbaud rate.

Figure 1: The HP Wedge inserts between

adjacent pairs of pins on a fine-pitch IC

package, providing secure, redundant,

mechanically noninvasive contact.

Johnnie Hancock is the worldwide

program manager for MCU debug-

ging tools at Hewlett-Packard in

Colorado Springs, Colorado, USA.

As Siemens chip designers packmore functions into their C500/166family of microcontrollers, pincounts of these powerful con-trollers have grown and the spacebetween pins has shrunk. Pin spac-ings of 0.5 mm and 0.65 mm are notat all uncommon for these devices.The power and added functionalityof these new MCUs is wonderful,to be sure, but troubleshootingdesigns based on these controllerscan be a chore because connectingscopes and logic analyzers hasbecome much more difficult andless dependable.

Engineers have tried a variety oftechniques to access the pins theyneed to test, but these probingtricks cause as many headaches asthey try to eliminate. For example,special fine-pitch IC clips can beboth expensive and fragile.Soldering lead extenders onto thepins of the microcontroller can

cause all kinds of problems, fromheat damage to the IC and shortsbetween adjacent pins, not to mention the chore of removing thekludge before you ship the fin-ished product. In addition, theadded inductance of the wireextenders can cause excessive dis-tortion in captured waveforms.

The HP Wedge probe adapter (seeback cover) is a handy new solu-tion to this problem. With thisdevice, you can probe up to 8 adja-cent I/O signals on Siemens MCUswith 0.5-mm and 0.65-mm pinspacing. All you have to do isinsert the HP Wedge between theIC pins you want to probe, whereeach compressible segment makessecure mechanical contactbetween a pair of pins (Figure 1).You then connect your scope orlogic analyzer to the other end ofthe HP Wedge. The HP Wedge alsoholds your probe in place, so it's ahands-free solution (Figure 2). It’seasy to use, cost effective, pro-vides excellent electrical perfor-mance, and doesn’t damage yourmicrocontroller.

Accessing fine-pitch I/O pins on Siemens MCUsBy Johnnie Hancock www.hp.com/go/bi

HINT

8HP Wedge

Figure 2: The HP Wedge holds your scope or logic analyzer probes in place, leaving your

hands free to run your system and your test equipment.

Electrical connectionbetween conductors

Two contactpoints oneach leg

HP Wedge

HP 54645D Mixed Signal Oscilloscope2 Scope channelsBandwidth 100 MHz

(75 MHz @ < 10 mV/div) Maximum sample rate 200 MSa/sMemory depth 1 M points/channelPeak detect 5 ns minimumInput impedance 1 MΩ, 13 pFMaximum input 400 V (dc + peak ac)Range 1 mV/div to 5 V/divResolution 8 bits

16 Logic channels Maximum sample rate 400 MSa/s one pod only;

200 MSa/s both pods activeMemory depth 2 M points/channel one pod

only; 1 M both pods activeInput R & C 100 kΩ, 8 pFInput level ±40 V max, 500 mVp-p minThreshold range ±6.0 volts in 50 mV incrementsPeak detect 5 ns minimum

TimebaseRange (main & delayed) 5 ns to 50 s/divAccuracy (non-vernier ranges)

Scope, same channel ±0.01% of reading ±0.2% of screen width ±40 ps

Scope, chan to chan ±0.01% of reading ±0.2% of screen width ±80 ps

Logic , same channel ±0.01% of reading ±0.2% of screen width ± (1 logic sample period, 2.5 or 5 ns)± chan-to-chan skew

Logic , chan to chan ±0.01% of reading ±0.2% of screen width ± (1 logic sample period, 2.5 or 5 ns) ± chan-to-chan skew

TriggeringSources All channels and lineLogic trigger modes Edge, pattern, glitch,

advanced pattern, TV Advanced pattern operators:

And, Or, Then, Entered, Exited, Duration time, Duration >, Duration <

Warranty 3 years

Ordering information and selected optionsHP 54645D Mixed signal oscilloscope

Includes two scope probes (HP 10074),one logic cable (HP 54620-61601), powercord and manual

HP 54645A 100 MHz 2-Channel oscilloscope with HP MegaZoom (analog-only versionof HP 54645D)

HP 54650A HP-IB Interface moduleHP 54652B RS-232/Parallel Interface module HP 54657A HP-IB Measurement/

Storage moduleHP 54659B RS-232/Parallel

Measurement/Storage moduleHP 1185A Carrying case106 HP BenchLink Scope software1CM 5062-7345 Rack mount kitW50 Additional 2-year warranty

• 2 scope channels and 16

logic channels

• Powerful triggering

• HP MegaZoom deep memory

View circuit operation in ways you’ve

never been able to see before.

No more guesswork and no morepoking around a few channels ata time.

Because the HP 54645D is builton a scope foundation, it looksand feels like a familiar scope—-not like a complicated logic analyzer. And the combination ofscope channels, logic timingchannels and HP MegaZoom deepmemory provides totally newways to debug mixed analog-digital and MCU–based designs.

HP 54645D Mixed Signal Oscilloscope

MCU DEBUGGING TOOLS

The HP 54645D mixed signal oscil-loscope combines the detailed sig-nal analysis of a scope with themultichannel timing measure-ments of a logic analyzer. Plus, itoffers the exclusive HP MegaZoomfor the benefits of deep memorywithout the usual drawbacks ofsluggish response and complexoperation.

By being able to see both the ana-log and digital sides of a problem,you can analyze the signals andrelationships that matter most.

The engineers at HP DIRECT canhelp you define the right solutionfor your MCU debugging needs.Call 1-800-452-4844.

Copyright ©1998

Hewlett-Packard Company

Printed in USA 11/98

5968-2498E

H

Although many accessories areavailable to connect scopes andlogic analyzers to fine-pitch ICs,some can cause as many problemsas they claim to solve. For exam-ple, typical spring-loaded alligatorclips fall off, they short adjacentpins, and they often lack the elec-trical performance to replicate thesignal faithfully. Specialized 0.5-mm clips are expensive and frag-ile. Poking around with a standard

scope probe risks damaging thechip, and soldering wires onto theIC certainly won't impress yourcustomers.

The HP Wedge provides accurate,mechanically noninvasive contactwith the pins of the IC under testby inserting compressible dualconductors into the space betweenadjacent pins. Its unique designdelivers secure, redundant contacton each pin, with no chance ofshorting adjacent pins or damagingthe DUT. Plus, the HP Wedgedoesn’t latch directly onto IC pins,so you can insert it while the boardis active. After you’ve established asolid connection, you can easilyattach the HP Wedge to scopes orlogic analyzers with the appropri-ate accessories.

Product IC pin spacing Number of Number of signals HP Wedges

HP E2613A 0.5 mm 3 1HP E2613B 0.5 mm 3 2HP E2614A 0.5 mm 8 1HP E2615A 0.65 mm 3 1HP E2615B 0.65 mm 3 2HP E2616A 0.65 mm 8 1

The HP Wedge probe tip adapter