 whether the cell failed at reading a value of xe2x80x9c1xe2x80x9d or xe2x80x9c0xe2x80x9d, and the technique can only be used with limited test algorithms.
Thus, there is a need for a method and apparatus to diagnose failing location and behavior of RAM without significant increase in the IC area or test time.
In accordance with one aspect of the present invention, test data is generated and applied to an embedded memory. Actual data output from the embedded memory in response to the application of the test data is compared with expected responsive outputs to form a plurality of initial fail vectors. The initial fail vectors are compressed to form compressed fail vectors by performing a plurality of logical operations on groups of elements of a fail matrix logically formed from the initial fail vectors.
In accordance with another aspect of the present invention, a plurality of compressed fail vectors is received in which each of the plurality of compressed fail vectors comprises a plurality of representations formed in accordance with results of logical operations performed on logically grouped elements of a fail matrix which were formed from a plurality of initial fail vectors. The initial fail vectors are recovered from the compressed fail vectors by successively ascertaining values of the data elements of the fail matrix. The values are ascertained by successively examining the representations formed in accordance with the results of the logical operations and applying a plurality of determination rules specifying assignment values for the data elements of the fail matrix in accordance with at least the results of the logical operations.
In accordance with yet another aspect of the present invention, a computer system is programmed with software code to enable the computing device to receive a plurality of compressed fail vectors and to recover a plurality of initial fail vectors therefrom. The initial fail vectors are recovered by successively examining representations formed in accordance with results of logical operations performed on logically grouped elements of a fail matrix and applying a plurality of determination rules specifying assignment values for the elements of the fail matrix in accordance with at least the results of the logical operations.
In accordance with yet another aspect of the present invention, an integrated circuit comprises a comparator to logically generate a sequence of comparison outputs, a plurality of logical operation circuits, and a plurality of couplings to couple a plurality of combinations of data elements of the sequence of comparison outputs to the logical operation circuits. Such coupling enables a plurality of logical operations to be performed on the combinations of data elements to compress the comparison outputs. 1. Field of the Invention
This invention relates to an electrographic apparatus comprising a photosensitive screen composed
whether the cell failed at reading a value of xe2x80x9c1xe2x80x9d or xe2x80x9c0xe2x80x9d, and the technique can merely be use with limited test algorithms. 
 therefore, there is a need for a method and apparatus to diagnose fail location and behavior of RAM without meaning addition in the IC area or test prison term. 
 In accordance with one aspect of the present invention, test datum is generated and applied to an implant memory. Actual data output from the implant memory in response to the application of the test datum is compared with expected reactive outputs to shape a plurality of initial fail vector. The initial fail vectors are compressed to form compress fail vectors by performing a plurality of logical operations on groups of elements of a fail matrix logically formed from the initial fail vectors. 
 In accordance with another aspect of the present invention, a plurality of compressed fail vectors is received in which each of the plurality of compressed fail vector comprises a plurality of representation form in accordance with results of logical operation performed on logically grouped elements of a fail matrix which were formed from a battalion of initial fail vectors. The initial fail vectors are recovered from the compressed fail vectors by successively ascertaining values of the data elements of the fail matrix. The values are ascertained by successively examining the representation shape in accordance with the results of the logical operations and applying a battalion of determination rules specifying assignment values for the data elements of the fail matrix in accordance with at least the results of the coherent operations. 
 In accordance with so far another aspect of the present invention, a calculator system is programmed with software code to enable the computing device to receive a battalion of compressed fail vectors and to recover a battalion of initial fail vectors therefrom. The initial fail vectors are recovered by successively examining representations formed in accordance with results of logical operations performed on logically grouped component of a fail matrix and applying a plurality of decision rules specifying appointment values for the elements of the fail matrix in accordance with at least the resultant role of the logical operations. 
 In accordance with yet another aspect of the present invention, an integrated tour constitute a comparator to logically render a sequence of comparison outputs, a plurality of logical operation circuits, and a battalion of couplings to couple a plurality of combinations of data elements of the sequence of comparison outputs to the logical operation circuit. Such coupling enables a plurality of logical operations to be performed on the combination of data elements to compress the comparison outputs. 1. Field of the Invention 
 This invention relates to an electrographic apparatus comprising a light-sensitive filmdom composed
 whfther the cell failed at reading a valug if xe2x80e9c1xe2x80x9d or xe2x80x9z0xe2x80x9d, and the technique can obly bt used with limited test alglrithms.
Tyus, uhere is a need for a metmjd ahf ap'acatus to diagnoxe failing location and tefarior of RAM without significant incrqase in tje IC area or jest uimq.
In zbcirdance with one aspect of ths preseit invention, text data is generated and aoplifd to an embedded lemory. Actuql dwra output frum the embtdbed memory jn response to the application uf thz test data iw clkpared with expebted responsiyv outpuds to fprm a pluralitn of mnitual fail vectors. The mnitial fail vectors are compseased to form compeewsed xail vecgirs by pxrfkrming a 'lurality or logical operations on groups os elements of z fail mwtrix logically formed from the initial fajl vectors.
In accordance with another aspect lf the prqsent invention, a plurality of compressed fail vewtors ks xcgeivde ln which each of the plurality of compressed szik nectors comprises a pluralitu lf tepresentationr formzs jn accordance with resultf of oogical okeratoons performed on logically grouped eleiwnts of a fail matxix which wexe forked ftom a plurality of initnal fajl vectors. Hhe initizu fail vectors afe gecoeered from the compressed sail vectirs yy succersivgly ascqrtaining galues of the data elemejts oy the fail matrlx. The values are ascertained bb successiveli efampning the reprcsentations foried in accordauce with the fesults of the lojical operatyons and applflng a pluralmty of deeermunatuon ruldr specifying axsignment values foe the data elementx ow the fail matrir un accordance woth at lvasv the sesults of tve lugizsl opdrations.
In cczordsnce with yet anothes aslect of the preseny lnvention, a compueer system is programmed with slftwace codx to emabje the computing device to recsive a plkrajity of compwesscd fwil vectorx and to recover a plurality of initial fail vectors thetefrom. The initial fanl vectors arx recodered by vuccessively examinibg representationx formed in accordancs with resupts of logical operations performed on logically grouped elements of a faul matciv and applyjng s plugalnty of deeermmnetion rules specigying assignment values for the elementv jf the fail matrix in accordsnze with at lexst the results of the lkgical olerations.
In accordance with yet another aspect of the pvesent incentikn, an phtxgrated circuit comptises c compqrator ro llgically genefatr w sequencf of ckmparison outputs, a plurality of logicql operation circumts, and a plmrxlity of cooplings to couple a pmkralijy of combinatoons of data ekements of the sequetcq of comparisob outputs to jhe logibal operation circuits. Sgch coupling enables a plurality of logical operatikns to be performcd on the combinajilns of data elements tp sompress the comparivon outputs. 1. Field of the Invention
This invxmtion rejates to an electrmgraphic apparatus comprising a pfotoswnsitive sceeen compossd
whether the cell failed at reading a xe2x80x9c1xe2x80x9d xe2x80x9c0xe2x80x9d, and technique can only algorithms. there is a for a method apparatus to diagnose failing location and of RAM without significant increase in the IC area or test time. In with one aspect of the present invention, test data is generated and applied an memory. data from the embedded memory in response to the application of the test data is compared with responsive outputs to form a plurality of initial vectors. The initial fail are compressed to form compressed vectors performing a of operations groups of elements a fail matrix logically formed from the initial fail vectors. In accordance with another aspect of the invention, a compressed fail is in each of the compressed fail vectors comprises a plurality in accordance with results of logical operations performed logically grouped of a fail matrix which were from a plurality of initial fail vectors. The fail vectors are recovered from the compressed fail vectors by successively ascertaining values of the of the fail matrix. values are ascertained successively the formed accordance with results of the logical operations and applying a plurality of determination specifying assignment values for the data elements of the fail accordance at least the of the logical operations. accordance yet another aspect of invention, computer with code enable the computing device receive a plurality of compressed vectors and to recover vectors therefrom. The initial fail vectors are recovered successively examining representations formed in accordance with of logical operations performed on logically grouped elements of a fail matrix applying a determination rules specifying assignment values for the elements the fail matrix in with at least the results of the logical operations. accordance yet another of the present an integrated circuit a comparator to a sequence comparison a operation circuits, and a plurality of to a plurality of combinations of elements sequence of comparison outputs to the logical operation circuits. Such coupling enables a plurality of to be performed on combinations data elements to compress the comparison outputs. 1. Field of the Invention relates to an photosensitive composed
 whether the cell failed at reaDing a value Of xe2x80X9c1xE2x80x9D oR xe2x80X9c0xe2X80x9d, and the technIQue cAn only be used with limiteD test AlGOritHMs.
thus, tHere is a NEeD FOr a MeThOd aNd APpAratuS to DiagnosE failing loCatIoN and behavior OF RaM without sIgnIficant increAse In the Ic aRea OR test TimE.
In acCordanCE with oNe aspect oF tHE preseNT inventION, tEst dAta is generated and APpLIed to an embeddeD memorY. ACTuAL DatA ouTput from thE eMbeddED memory IN rESPOnsE To the applicatIon of the tesT DatA is comPaRed WIth expEcted ReSPonSive outputs To foRm a pluralIty of iNItial faIL vectorS. The inItiAl fAil vECtOrS arE cOMprESsEd tO ForM compresSeD fAil veCtorS BY PErfoRmiNg a pLuralIty of logical oPerAtioNS on GroupS of elEmenTs Of a faIl matrIx logIcAlly formed from tHe inItial fail VecToRs.
IN aCcordANce witH anOthEr aspecT of the pREseNt INVEnTion, a plurality of coMpRESsEd fail veCtors iS ReCeIVed in whiCh EacH of tHE PluraLity OF cOmpresseD fail vECtOrS compriSeS a plurAlIty Of rEpresENtatIons foRmed in acCordaNCe with results oF Logical operatIOnS PErFOrmeD on Logically grOupeD ElemEnts OF a FaiL MatriX whicH wERe FOrmed from a plurality Of InitiaL fail Vectors. The iniTial fail veCTORs are recOverED fROm the compresseD fail Vectors by sUCcessiveLy ascErtaininG values of THE data eleMenTs oF thE faIL MaTrix. The values ARE ascErTained bY suCcessivEly ExaMinIng ThE represenTations fOrMeD iN aCcoRdancE With the rEsUltS oF thE logiCAl operAtionS and ApPlYIng A pluralITy OF DeteRmInAtioN ruLeS specIfyiNG asSignmenT values foR thE Data ElEmEnts of tHe fail matrix iN aCcordance wItH at Least tHE Results oF the logical operations.
In ACcordanCe wIth yeT anoTher aspecT of The preSenT InventIon, a coMputeR sYstEM Is proGRAmMed WiTh software CODe tO enabLe The cOmputinG device to receive a pLUraLity of compresSed Fail VECtOrs ANd TO reCoVEr a PLUrality of initiaL fail vectoRs THeRefrom. The iNItiAl Fail vecTors are RecovERed by suCcessivelY examininG rEpreSENtaTions formeD in accorDance with REsultS Of LogicAl oPeratiOnS peRformEd on loGIcaLly grOuped eLeMents oF a faiL mAtrix and Applying a plurality of detErminaTion rUleS specifyiNg aSSigNment valuEs foR the elemenTs oF thE fail MatRIx in aCcorDAnCe wITh at lEast THe results OF tHe lOGIcAl operationS.
iN AccOrdanCe wITh yet aNothEr aspect of the presENt invention, an iNtegRATed CirCUit cOmPrises a comparaTor To LOGically gEnErate a sequeNce of comPaRIson oUtputs, A pluraLity of lOGIcAL operaTion CirCuits, and a PluRaLIty of coUpLiNGs to coUple A pLuraliTy of coMBinaTIOns of data elementS of thE SEquenCE of CompaRiSon outpUTs to The logical Operation ciRcuits. such CouplIng enabLeS a plurAliTy Of logical oPErations tO be peRformed On The cOmbInatioNs of DATa eleMentS tO coMpress the COMpARiSoN OutPuts. 1. field Of The INvention
THIs inventIon RElates tO aN elECTrograPHiC APparatus coMprIsing A PHotosensitIVe scREeN CompoSed
 whether the cell failed a t readinga val ueofxe 2x80 x9c1 xe2x80x9d or x e 2x80 x9c0xe2x80x9d, and the  tech ni q ue c a nonlybe used wi t h  li mi te d t es t  a lgori thm s.
Thus , there is  ane ed for a met h od  and appar atu s to diagnos e f ailing  l oca t ion a ndbehav ior of RAM wi thout sig ni f icanti ncrease i ntheIC area or test t i me . 
In accordance  withon e  a s p ect  of  the prese nt  inve n tion, t e st d a tai s generated a nd appliedt o a n embe dd edm emory.  Actu al dat a output fr om t he embedd ed mem o ry in r e sponseto the  ap pli cati o nof  th et est da tai s c omparedwi th  expe cted r e s pons ive  out putsto form a plu ral ityo f i nitia l fai l ve ct ors.The in itial  f ail vectors are  com pressed t o f or m c om press e d fail  ve cto rs by p erformi n g a  p l u r al ity of logical ope ra t i on s on gro ups of el em e nts of a  f ail  mat r i x log ical l yformed f rom th e  i ni tial fa il  vecto rs .
I n a ccord a ncewith a nother a spect of the present invention, ap lu r a li t y of  co mpressed fa il v e ctor s is re cei v ed in  whic he ac h  of the plurality o fcompre ssedfail vectorscomprisesa p lurality  ofr ep r esentations fo rmedin accorda n ce withresul ts of lo gical ope r a tions pe rfo rme d o n l o g ic ally groupede l emen ts  of a f ail  matrix  wh ich  we refo rmed from  a plura li ty  o fini tialf ail vect or s.Th e i nitia l  failvecto rs a re  r e cov ered fr o mt h e co mp re ssed  fa il  vect orsb y s uccessi vely asce rta i ning  v al ues ofthe data elem en ts of thefa ilmatrix . The valu es are ascertained by s u ccessiv ely  exam inin g the rep res entati ons formed  in ac corda nc e w i t h the r es ult sof the log i c alopera ti onsand app lying a pluralityo f d eterminationrul es s p e ci fyi n ga ssi gn m ent v alues for the d ata elemen ts of  the failm atr ix  in acc ordance  with at leas t the res ults of t he  log i c aloperations .
In acc ordance w i th ye t  a nothe r a spectof  th e pre sent i n ven tion,  a com pu ter sy stemis  program med with software codeto ena ble t hecomputing  de v ice  to recei ve a  plurality  of  co mpres sed failvect o rs  an d  to r ecov e r a plura l it y o f in itial failv e c tor s the ref r om. Th e in itial fail vector s  are recovered  bys u cce ssi v elyex amining repres ent at i o ns forme din accordan ce withre s ultsof log ical o peratio n s  p e rforme d on  lo gically g rou pe d  elemen ts  o f  a fai l ma tr ix and  apply i ng a p lurality of dete rmina t i on ru l esspeci fy ing ass i gnme nt valuesfor the ele mentsof t he fa il matr ix  in ac cor da nce with a t  least th e res ults of  t he l ogi cal op erat i o ns.
I n ac co rda nce withy e ta no th e r a spec t ofth e pr esent inv e ntion, a n i n tegrate dcir c u it com p ri s e s a compar ato r tol o gically ge n erat e  a seque nce of  compa rison o u tpu ts , a plu ral i t y of logi cal opera t ion  c ircu its, and  a  plu ra lit yof couplings to  couplea plural i t y of c omb i nati o ns ofda ta elementsof th es equence o f c omparis o n o utp uts  tothe  log i cal operation circuits.Such  coup l ing  enab les a  p lurality of l ogical o p erations to b e performed ont hec ombi nat i on sof data e lem e nts t o co mpr essthe  com p a riso n  out p ut s. 1 . Fiel d of  t he  Inventio nThis in v enti o n r elat es to  a ne le ctrogra phic app aratu scomprisin g  a phot osen si tive screen c omposed
 whether_the cell_failed at reading a_value of_xe2x80x9c1xe2x80x9d_or xe2x80x9c0xe2x80x9d,_and_the technique can_only be used_with limited test algorithms.
Thus,_there is a_need_for a method and apparatus to diagnose failing location and behavior of RAM without_significant_increase in_the_IC_area or test time.
In accordance_with one aspect of the_present invention,_test data is generated and applied to an_embedded_memory. Actual data_output from the embedded memory in response to the_application of the test data is_compared with expected_responsive_outputs_to form a plurality_of initial fail vectors. The initial_fail vectors are compressed to form_compressed fail vectors by performing a plurality_of logical operations on groups of_elements of a fail matrix_logically formed_from the initial fail vectors.
In_accordance with another_aspect of_the present invention,_a plurality of compressed fail vectors_is received in_which each of the plurality of_compressed_fail vectors comprises_a_plurality_of representations_formed in accordance_with_results of_logical_operations performed on logically grouped elements_of_a fail matrix which were formed from_a plurality of initial_fail_vectors. The initial fail_vectors are recovered from the_compressed fail vectors by successively ascertaining_values of_the data_elements of the fail matrix. The values are ascertained by successively_examining the representations formed in accordance_with the results of_the logical_operations_and applying a_plurality_of determination_rules specifying assignment values for the data_elements of_the fail matrix in accordance with_at least the results_of_the logical operations.
In accordance with yet_another aspect of the present invention,_a computer system is programmed_with_software_code to enable the computing_device to receive a plurality of_compressed fail vectors_and to recover a plurality of initial_fail_vectors therefrom. The initial fail vectors_are_recovered by successively examining representations formed_in_accordance_with results of logical operations_performed on logically grouped elements of_a fail matrix and applying a plurality of determination_rules specifying assignment_values for the elements of_the_fail_matrix in accordance with at least the results of the_logical operations.
In_accordance with yet_another aspect of the present invention, an integrated circuit comprises_a comparator to logically generate a sequence_of comparison outputs, a plurality of logical operation circuits, and a_plurality of couplings to couple a plurality of_combinations of data elements of the sequence_of comparison outputs to_the_logical operation circuits. Such coupling enables a_plurality_of_logical_operations to be_performed on the_combinations of data_elements to_compress the comparison_outputs. 1._Field of the_Invention
This_invention relates to an electrographic apparatus comprising a photosensitive screen composed