Inter-Office MemorandumToDorado ProjectDateApril 18, 1980FromEd TaftLocationPARC/CSLSubjectDorado Board TesterFile[Ivy]BoardTester.pressXEROX The Dorado board tester is used for static testing of Dorado logic boards, either stuffed or unstuffed,to verify the continuity of all nets and the absence of shorts between nets. It also has a limitedability to detect stuffing errors (e.g., backward SIPs) and leaky gates.The tester operates by measuring the resistance between each pin of each IC and the power andground planes (which are shorted together). For ECL nets, this resistance can be predicted on thebasis of how many terminating resistors the net has. A discrepancy between measured and predictedresistance is an indication of an error. For example, a net that is broken will show higher resistancethan expected on some or all of its pins, while a net that is shorted to some other net will showlower resistance than expected (assuming the other net has at least one terminator).Physically, the board tester consists of a low chassis containing Dorado edge connectors into which aDorado board may be slid. The chassis contains a small quantity of electronics and a cable thatconnects to the Diablo printer port of an Alto I. Any of various probes may be plugged into thechassis, including 16- and 24-pin DIP probes, a QIT package probe, and a single probe for testingother types of packages. Finally, there is a button mounted on the side of the chassis and a footpedal, either of which may be used to advance from one IC or pin position to the next.A program called Resist exists (file [Ivy]Resist.run) for driving the board tester. It reads inthe wire list for the board being tested (e.g., ProcH-Rev-Ce.wl) and a data file containinginformation about what resistances to power and ground to expect at each pin of each IC (e.g.,ProcH-Rev-Ce.resist). It then interacts with the operator to test each IC position, and produces anoutput file describing any errors that are detected (e.g., ProcH-Rev-Ce-SN-0123-U.defects, where0123 is the board serial number and U indicates that it is unstuffed). This file may in turn be usedas input to the program, to assist in tracking down and correcting errors.Usual test procedureThis is a prototype procedure for testing a new Dorado board. Many variations are possible, andundoubtedly this procedure will be improved as experience is gained with it.1. Mount the boardSlide the board into the top slot of the tester and close the connector jaws. Make sure the contactsline upthere is a lot of slop in the connectors.If the board is not stuffed, plug SIPs into all terminator positions. For bare Multiwire boards, thereexist SIPs with special plugs on all their pins. Plug into the chassis the 16-pin DIP probe and theQIT probe with spring-loaded pins.]gpi c8q]rX -q5`r \q]r-q5`r VDq]r-q5`"Osr I52 HL FH CH B%?# @T ?!F = T <T 90] 7[ 6(L 4Y 3 H 12$ .e -3F +"< *+a (F '#U %J !tX .r)7 L uX  r32 1 F!  d " T>/ZDorado Board Tester2If the board is already stuffed, just plug in the 16-pin and 24-pin DIP clip probes.Plug the black cable into the Diablo printer port of an Alto I.Caution: Make sure the chassis does not contact ground. The chassis is part of the test circuit, so ifit is grounded the tester will not work.2. Obtain data files and start Resist programUse FTP to load the two required files, extensions .wl'' and .resist'', from the dump file for theboard you are testing. Make sure you use the correct technology (stitchweld or Multiwire) andrevision. For example, load files ProcH-mwRev-Ce.wl and ProcH-mwRev-Ce.resist from[Ivy]ProcH-mwRev-Ce.dm. (At present, for some boards the .resist'' file is storedseparately rather than as part of the dump file.) There is an optional .exceptions'' file (e.g., ProcH-mwRev-Ce-U.exceptions or ProcH-mwRev-Ce-S.exceptions, for unstuffed and stuffed boards,respectively); if one exists you should retrieve it also.Start the Resist program with the command:Resist filenamewhere filename is the name of the .resist file. (If you are testing a BaseBoard, or any other boardthat uses 40-pin ICs, you must supply the additional parameter 40/P'' in the command line.)Resist asks you to supply the board serial number (followed by RETURN), and also asks youwhether or not the board is stuffed. It then churns away for about a minute while it reads the inputfiles; most of the display is black during this time. When the main part of the display appears,Resist is ready for you to begin testing.3. Test the boardBelow the system window at the top of the screen, there is a window containing the current boardlocation and instructions about what to do next, another window showing the current reading of thesingle probe, and a large window showing the current readings of all the pins of the DIP probe,along with the pin numbers, expected resistances, and net names where known. (A net name of ?''indicates that the pin is not mentioned in the wire listeither it is trace-wired or it is not connectedto anything.)Resist tests ICs in the following order:1.All 16-pin and 14-pin packages2.All 24-pin DIP packages3.All QIT packages4.All other packagesWithin each group, ICs are tested in alphabetical order by board location.When you are at a 14-, 16-, or 24-pin DIP package or a QIT package, Resist asks you to install theappropriate probe on that package. The resistance measurements in the bottom window arecontinuously updated, and pins whose readings are out of spec are displayed with a blackbackground. When you have installed the probe correctly, all the black bars should go away; if theydon't, either the probe is installed incorrectly or there is a real problem with the board. When youare satisfied that the probe is installed correctly, press the button, the foot pedal, or the space bar onthe Alto keyboard to advance to the next IC. (The test results saved in the output file are sampledat the instant you press the button or whatever.)When Resist is testing an IC position with an oddball package, it asks you to put the single probeon each pin in turn and press the button. In this case, the DIP measurements in the bottomwindow are accumulated one pin at a time. When you have done this for all pins, Resist then waits frXG bT _9? \Ttr_ Z( WuX- T3rT R^ Q+S TI OZ N#28 L/C0 K9 H6*EQu BlrurG @M >#6 <=( :#> 9w) 5uX 2r` 1UG /_ .MM ,h +E (`( %| # "s   J &11 B P =' a N  22 1 M M =% U>/]4Dorado Board Tester3for you to press the button once more before advancing to the next IC.It may happen that Resist asks you to mount a DIP or QIT probe on an IC position for which thatis impossible (e.g., because it contains an IC with legs cut or wires soldered on). In this case, typeS'' to cause Resist to test this IC using the single probe rather than the DIP or QIT probe.The board tester contains an audible signal that may optionally be enabled by means of a switch onthe side of the chassis. If enabled, the signal will sound whenever one or more of the measuredresistances is out of spec. (While you are using one of the DIP or QIT probes, the signal is disableduntil you have lifted the probe from the previous IC position and placed it in contact with the newone.)4. Finishing upWhen you have tested all IC positions, Resist writes the .defects file and exits to the Alto Executive.The .defects file name includes the board serial number and unstuffed/stuffed indication; e.g.,ProcH-mwRev-Ce-SN-0123-U.defects for an unstuffed board or ProcH-mwRev-Ce-SN-0123-S.defectsfor a stuffed board. At this point, you may examine the .defects file using Bravo, print it usingEmpress, or whatever.At the end of the .defects file is a summary of errors found, organized by net. Each net thatexhibited any errors is shown, with the resistance measured at each pin. Within a net, the pins areshown in the order that they are wired on the board; however, only those pins that are mentioned inthe .resist file are shownedge pins, terminator pins, and the like are not shown. A measuredresistance of --'' means that the pin was not tested; this occurs only if you skipped over boardlocations or Quit'' before testing the entire board.You can also re-run Resist using the .defects file as input (instead of the .resist file). When you dothis, Resist tests only those IC positions for which errors were reported. This gives you anopportunity to eliminate any errors that might have been caused by operator error, bad contact withthe probe, etc. When Resist finishes this time, it writes the updated results on top of the input file,after saving the input file by appending $'' to its name (just like Bravo).When you are satisfied that all the errors reflect real board problems, then, for an unstuffedMultiwire board, you should print the .defects file and put it in the board log as a record of whatmodifications must be made to the board after it is stuffed. For a stuffed board, you shouldproceed to find and correct the problems.5. Other detailsIf a test is interrupted (either by the Alto failing or by your issuing the Quit'' command), you canrestart it simply by issuing the command Resist/R'', with no other parameters on the commandline. Resist will resume the test at the point of interruption. You must issue the Resist/R''command immediately after the interruption; if you start up Resist without the /R'' switch, you willlose the information required to restart the previous session.All pin numbers are counted on the package, not on the board. In particular:14-pin DIPs have pin numbers 1 through 7 up one side and 8 through 14 down the other.The Resist program tests 14-pin DIPs using the 16-pin DIP probe, which you must positionso that pin 1 of the probe contacts pin 1 of the 14-pin DIP.QIT packages have pins numbered 1 through 24, starting in the usual corner and proceedingcounterclockwise. However, Route (and therefore Resist) believes that a QIT package has26 pins, because that is the number of pins on the QIT platform (the last two pins are extragrounds). If you test a QIT package position using the single probe, you must hold theprobe on pin 24 while advancing the Resist program through pins 25 and 26. frXG bF _9A ]8/ \1F YL?# WD VD@& T(; S< OuX Lrg K#< I1* HY F C// B%[ @B! ?R =7+ <6 90g 7] 6(K 4h 3 M 0;2, .R -30- +) 'uX %rb #> " "? u r4 > M8990<KH8C\F ;J ?/[HDorado Board Tester4The board tester's resistance range is limited to about 150 ohms; resistances greater than that arereported as open''.The Resist program will optionally read an additional file, with extension .exceptions'', whichcontains exceptions to the .resist file. The .resist file may be incorrect due to the presence of analogcomponents, configuration jumpers, and other aberrations that Route was never told about. Toavoid having these show up as errors every time a particular board is tested, you can prepare an.exceptions file containing the corrected information for each affected IC position.The .exceptions file has the same format as the .resist file and should be created by editing eitherthe .resist file or a derived .defects file. (This procedure should be used in preference to editing the.resist file, since such edits would disappear whenever a rework was performed.) The name of the.exceptions file must be in the form ProcL-mwRev-Ce-U.exceptions or ProcL-mwRev-Ce-S.exceptions, where the board name and revision level match those of the .resist file, and the U or Sindicates that the file is applicable to unstuffed or stuffed boards. If a .exceptions file with theappropriate name exists on your disk, Resist will read it automatically when it starts up.Resist commandsThe following is a complete description of all commands and facilities available in the Resistprogram.Command lineThe general form of the command line for starting Resist is:Resist/global-switches parameter/switch parameter/switch ...The global-switches may include any one of the following:/RRestart an interrupted session. (If you specify this switch, you should not supplyany parameters on the command line.)/SThe board being tested is stuffed./UThe board being tested is unstuffed. If you don't specify either /S'' or /U'',Resist will ask you for this information right after it starts up. (If you are reading a.defects file rather than a .resist file, Resist extracts this switch from the name of thefile.)A parameter without a switch specifies the input file name; there must be at most one of these. (Ifyou don't specify one, Resist will ask you for it right after it starts up.) Other parameters are asfollows:number/SThe board serial number. (If you don't specify this, and Resist needs it, it will askyou for it right after it starts up. If you are reading a .defects file rather than a.resist file, Resist extracts the serial number from the name of the file.)number/PThe maximum number of pins permitted on any IC. The default is 26; you mustspecify 40 for a BaseBoard. (Increasing this number increases the size of thedisplay, which reduces the amount of memory available for storing the informationin the .resist and .wl files.)number/TThe error tolerance, as a percentage of the expected resistance. The default is 12.location/LThe location of the first IC to test. frXG bF ` ]5, \1R Z,1 Y)F WT TP S<V Q9( P4E$F/ NP M,S KZ GtX D7r*4 B >uX <r<90ururururu 6Krur& 3g I1ur ." ,D*G)>' $ur ur* #$\ ! urJ 7%1K ur+!J3+&B ]urK xur% V 1>/Y>Dorado Board Tester5An example of a fairly complex command line is:Resist/U ProcH-mwRev-Ce.resist 40/P 123/S 10/TInteractive operationAt any time when Resist is expecting you to press the button to advance to the next IC or pin, youmay type any of the following single-character commands:SingleTest the current IC using the single probe rather than the DIP probe. If you issuethis command when you are already using the single probe, you will reset Resist topin 1 of the current IC.DIPTest the current IC using the appropriate DIP or QIT probe rather than the singleprobe.Back upBack up one pin. This command is meaningful only when you are using the singleprobe.IgnoreIgnore this IC: that is, advance to the next IC, but do not write anything into the.defects file even if there are errors. Use this command when you know that anerror is benign (e.g., due to a component with legs cut for configuration purposes).LocationGo to a new board location, which you must then type in (preciselye03'', notE03'' or e3''). Resist proceeds to test ICs beginning at that location, withoutremembering about any locations you may have skipped over. You can only specifylocations that are mentioned in the input .resist (or .defects) file.QuitExit to the Executive. Resist will quit without putting anything into the .defectsfile; however, you can later restart using Resist/R'.Resist, Defects, and Exceptions file formatThe .resist, .defects, and .exceptions files are text files containing information about each IC. Textbetween a semicolon and a CR is a comment and is ignored by the Resist program. A .resist filecontains information about all ICs on the board (as well as some other component positions such asterminators and bypass capacitors, which are ignored by Resist). A .defects file contains the sameinformation, but only for those ICs for which errors were detected; following each IC description areone or more comments describing the error. An .exceptions file contains manually-preparedcorrections for specific ICs in the .resist file.An IC description is:location (package-type, number-of-pins, IC-type) resistance, resistance, ...The location is a board location in standard format (e.g., g13'' or #-1f13''). The package-type isone of DIP3 (.3-inch wide DIP), SIP, or OddPkg (anything besides a DIP3 or a SIP). The IC-typeis the full IC designation (e.g., MC10176''); in a .resist file (but not in a .defects file), someadditional information appears after a /''it is ignored by Resist.The remainder of the description consists of the expected resistance at each pin, from pin 1 to pinnumber-of-pins. A short is indicated by 0'' and an open circuit by $''. If the resistance at a pincannot be predicated, this is indicated by ?''. frXG b/_9. [uX XrK W8 ST3I R=Q+ MNFJL II-HY EEtACB Bl> ?0?/>9<'):E 78F 66 2tX+ /!r;, -P ,/3 *Q )C" '., & 1 #$ ?uru ru ruru ru r Zur6u r Su Rr22 E c eu r: 1 >/UqG TIMESROMAN  TIMESROMAN TIMESROMAN LOGO TIMESROMAN  TIMESROMAN   #+j/.,'hBoardTester.bravoTaftApril 18, 1980 11:45 AM