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software notes - Altair 8800 Clone

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2. i Page Nac pesi moi Larim Dn Tair Emi mcam m E E Eeit nz ul im LIS RA m arg d M a TE m nen m po A LE muc le mmi mm Kin m d J a cumin B Wr Lu idit d eur EC E oum or mri amor m C m m THES hes m Es RETO Hi mes m 1 nma um WM mm eur LI Vul mg FI LLL Erari o di Lin m T EL sd mam mmu E ds ges mr imt acd TET TET Tee iit MTT Tree terete Ti kEm ei i LEFEL Jurna 1977 It s a jungle out there crawling with publications that deal with every aspect of home and business computing from spacey games to inventory accounting and process control There s a lot you need to know to find your way around COMPUTER NOTES offers a monthly survival kit of easy to understand features on computer hardware software and unique applications CN is published by MITS Inc the Altair people Each issue is a
3. THENS5a 658 IFMIDS XS 1 K1 lt gt THENTL T TH Ttl I K11ONZZGOTO7T6 1000 l 1 K1l1GOSUBT9IO TL T 1 688 ISI KITFORKESKITOK3 IFHIDSCXS I K12 MIDSCKS KK IDOTHENHEXT1G0TO1808 590 ONKGOTO6893 799 712 lel 1GOSUBT3S 560 07 38 718 IFZZ lt gt K1 THEN 1068 728 TLsABSCTO TLSPCITHseT TLITL sT TL 739 IsI4KI IFI LORMIDS amp CXS2IKI1 22 THENRETURN IFMIDSCXS I4 Kl1 z THEN730 758 GOTOIG2O 768 RETURN CONTINUED 790 TISVALCMIDSOXS 12 FIFTEEN Circuit Analysis Applications CONTINUED 8 The format used here falls somewhere in between these two extremes It s not a particularly simple program but it s straightforward Although it doesn t allow a completely free format it s fairly easy to learn Input Format See the sample runs for the input format Branches are described with the letter as the first non space character and followed by the branch number A node is followed by two node numbers in parenthesis The first number is the initial node of this branch The second is the final node Initial and final nodes are determined by the positive current direction in the branch which is set arbitrarily by the user Current flows from the initial node to the final node Then the component values in the branch are entered in any order defines resistance G defines conductance E defines voltage source and defines independent curren
4. CP 1 lt 57 HENCE CE CHAS iG FL GOI 0653994 32ANDEL 221 HENG 2999 rj 6 3996 TFF lt gt 5 lt gt 6 3995 Fe 521 6 9 PHINITPRINI ERROR LINE s EACCOH rNULLAaOTEND POR 33 60 063998 GO 969995 PRIMIRIGHI ECKE LENCKE Ji e FL PF Ges 32ANDGe 441 HENG 3994 PRIN CHRECG317601063998 FOURTEEN A circuit is a group of components with fixed characteristics interacting in some prescribed manner electrical engineer s job is to develop mathematical relationships between the various components of a circuit that describe the total behavior of the network n order to develop these relationships electronic circuits must be analyzed Computer analysis of electronic circuits is nothing new in itself However this program brings automated analysis to the Altair computer running BASIC It is therefore inexpensive to Implement and easy to modify for special needs The analysis technique and output formats used in this program are based on those in IBM s ECAP Electronic Circuit Analysis Program written for the 1620 The input format is slightly different than ECAP s Although ECAP does three different types of circuit analysis this program does only steady state D C analysis The soluti
5. 50c E Computer Notes is continually seeking quality manuscripts on applications troubleshooting interfacing software book reviews fiction cartoons and a variety of other computer related topics Articles should be a minimum of 800 words and a maximum of 3600 words long about 15 pages typed double space Honorariums are based on an article s technical quality and its suitability for readership Payment will range from to 1 per typeset magazine column inch for all text and programs payment will be made for illus trations All articles are subject to editing to fit space requirements and content needs of our readership Payment for articles which are accepted will be sent upon publication Articles submitted to C M should be typed double space vvith the author s name address and the date in the upper left hand corner of each numbered page Authors should also include sentence autobiographical statement about their job professional title previous electronic and or computer expereince under the article s title Authors should retain a copy of each article submitted All illustrations diagrams schematics and other graphic material should be submitted in black ink on smooth white paper Prints and PMT s are acceptable Mo pencil drawings unless properly fixed No halftone or wash drawings Whenever possible art should be done to fin ished size Complicated drawings should
6. ct E T PPlHT nO0l DELLTE LILES 60 ABL FE FImW POLE 000 33 PURE EDDI LEE EGOE 51 TWEE 5003 FOS 1294 LIE P l 3l FUE EUTG E007 s gll PUKE E9259 19 sPORE FLI 2 zo POLE 116 PORE FOLZ 31 POLE 913 POLE 5014 70 PORE 015 11 tPORE 016 TOKE 017 gt l PORE 0 219 0 6020 ZUE POLE 021 LIE 2 31 IEE ZSA 255 POER 6 09 PORE ELl 1PULE iPOEEL LUE 35 PORE E030 3 E031 PURE 5 PUI 6033 185 zOkE EDSA 194 PULL 035 Fa POKE 1036 31 6037 295 P LE EJIE LIE POLE E6035 31 2040 62 POLE 7 PORE ZL PULE EJAJ 5045 COS PORE 045 u llt POKE 046 31 POKE EDAT POLL a 211 sPOHL 050 TORE EQS 195 67 4POKE 2053 4 al PORE 4 219 FOSS 16 PORE 056 31 PORE 057 31 IF KE 210 PORE EGS gt LIE PORE 0660 311P O0LEE amp D61 201 ZEB 624 24170 EEO 6320 S TOF VIml O rlIASsEQ D1Is65 D2Az56 L3z671 L z6E 64 QUTI3040szD0T T131 255z 0l T1 TICE GOT TLlES eSEE OUT pu 04 134 0 EE TIJ3E40 DUTI23220130T1 T1324
7. 100 27 GG LARE DLISPSLA 150 FOR 1 0 64705207 PULL 1 321 200 POLET73a 64 P LE 74 211 SLT 1512 1009 1000 gjs D 79 SE 66 6051 744 8040 5500 OUT dad PERF i Ful EBD 7 66255 UkEEO 17 27 55 POLELOTEESES 5700 S100 6200 50 6500 6519 6530 6540 7109 7100 FOF 1 00 7300 7350 1400 IF 7410 06655 THEN 6500 POREED 66232 a dE PORECO POLED 75 5000 0517190 64 1 1 32 6 L PUERCO 70 2L 3432 POLLE J 65 C1 438 1POLEEOSEC2B 432 70 SED 71 OLEEERO POEEED 66 01 659 L UM Tea D 5000 TOILStOUTISGICEsQ0TU TIZS cr 11 133 1151 a5 Vetcl 6t5S 00L5S 16 AELDI 52 5 VI A05 5 lal gt Gist TREN Chel DIAS 211 M420 IF 2 THEN L2sIHT CV 7430 IF 3 TEE SINT 7440 IF THEN L3eISNUT CV 7480 IF C5 TREN C3 2IHT CA V 7460 IF i 7470 IF Ch 7 7650 5000 g 02 8500 5501 5502 6590 Chee BREAD 55 THEN gt 1 5000 DATA 35 35 43 36 26 432 37 37 43 3 3 42 26 26 41 40 40 43 41 41
8. Reset Afer the Altair 680b is powered up the 6800 microprocessor can be programmed to start executing at any memory location This differs signif icantly from the 8080 microprocessor in which the 8080 program counter 15 cleared with reset and execution starts at location 0 The 6800 is reset when RES reset pin 40 of the 6800 is low for eight clock periods reset operation involves retrieving the contents of memory location FFFE and FFFF and loading this information into The program counter The microprocessing unit MPU then starts execution at the location indicated by the program counter Notice that in the Altair 680b locations FFFE and FFFF are located inside the PROM monitor When the 6800 microprocessor 15 halted and the Reset switch is held is low BA and R W are high read state and the address bus contains the restart address FFFE Address lights Al 415 are then on and the AO light is off when the Reset switch is held When the Run Halt switch 1 moved to Run the 6800 reads from FFFE and FFFF storing the byte In FFFE in the upper part of the program counter and the byte in location FFFF in the lower part of the program counter The 6800 then jumps to the location pointed to by FFFE and FFFF Monitor Operation During Reset When the 6800 starts executing the instructions the instructions pointed to by locations FFFE and FFFF resets the ACIA and
9. The line number referenced to in the error message is in the original program This can occur if the resequencer is asked resequence a line that does exist How Does the Resequencer Work Resequencer runs through program three times The first time it looks for the first OLD line When if is found the system examines the program line by line counting lines as it goes It stops when if reaches its own first line number On fhe second pass it gathers 50300 50319 BASE D amp INTERCHANGE REAL ae 1 AND 1 t June 1977 mecum deem future GOTO and GOSUB references Resequencer displays the number of lines the program contains It tells the user to READ Y PUNCH and then pauses while the operation is performed Starting leader and control 0 are punched automatically to prevent echo On the third pass the program begins listing Each initial line number is the incremental step from the previous line number Referenced line numbers are then a function of the startin parameters and the position of a lin number in the array The resequencing and listing stop when the program reaches its starting line number It then resets nulls to zero prints an END to undo the control 0 echo suppression and spills out some finishing leader Since resequencer starts looking for the old first line in the top part of BASIC there is a slight chance that it IY IWTERCHAN
10. 10 CLEAR99 1M SBITDEFFNMICXOSINT C X 28 amp X IMPUT NHODES XMNuaFNICC 13 28 INMPUT BRANCHES 2X M4BzFMICK IO INPUT DZP SCS IX MDSFHICX 12 DIM M MBMN HICHBO MF MB AZUCHSI 1 MM YHD YLAB YHB CUCMB DIM A MHBO2 ALOIB 4 AHCHBO ECMBO EL H B 4 EHCMB 4 D CM D 4 DLCMDO DHCMD 58 DIM EQ MND IPCHNONUCMN INCHN L W HN J VLCHNO VHCHN DIM RV MDO CL4MD2 5D CHN 1DS2a NBG XC MM iC amp s BDSGREILD PRINT PRINT ALTAIR DC ECAP ItPRINT PS a CHBUEVECPLPDVCSDXUBCCU IH K0s21 1 2 2 B 5 5 5 6 7 7 1 9 9 HN KM IN BE KM KM t N Yn KM tN En KM 1H Am CV 90 1308 031155236 118 PReKe 128 INPUTXS 131 5 lt gt 159 130 IFN Y NWAAND NE gt gt XM AN DN gt gt KMTHEN 1858 148 1 REQUIREMENTS FOR SOLUTION MET END 158 IFXSs M4ODIPFY THENMOsSMO KI 1GO0TO128 160 IFLEFTZCXRSZ KlI22 R THEWI2 178 IFX amp u HEWJ THENIG 189 IFLEFTSOXS4 K5 2 PRINT THENInKS GOTOS3O 190 IFXo END THENEND 200 ISI KIS IFI LTHENI2S 210 FORKSKITOXAS 1FMIDSCXSAIG KI2 HIDS CCS K K1 THENNEXT 1GOTO 1080 ecd ONKEG TOSZHB 2330 232 470 838 TYsX X11G805UD5201X2sT K1 IFTY2SK2THEN2D ED 240 IFXHEBTEEWHSPRINT BRANCH TOO GREAT GOTOIO 38 250 IFHOTHENA4T3 268 RECORDS CANNOT FOLLOW D RECORD
11. Each branch may have a voltage source current source or dependent current source Since this program has only steady state D C analysis the circuit must have at least one independent source one node other than ground and one branch Every node must have a path to ground through the branches of the circuit Without the path to ground certain sections of the circuit would float free of the rest Starting with the number one each node is numbered in increments of one Ground is always node zero Branches and dependent current sources are numbered consecutively from one There is no branch or dependent source zero Output from the solution is in terms of these numbers Input Program The input program 15 compromise between ease of programming and ease of use The easiest program to write might ask for the number of branches and then quiz the user on the values of it s components and the nodes to which it is connected This would require a lot of operator and computer time that could be put fo more productive use The easiest program would permit a user to enter and edit any data in any order any time But such a program would be rather complicated to write 1977 ma Um cmm mom p T ERU Ln mm mens em mom ALTAIR DC ELECTRONIC CIRCUIT ANALYSIS PROGRAM ADAPTED FROM IBM 1628 ECAP ALTAIR BASIC VERSION 3 2 4 8 gt BY TOM SIMPSON 2 14 77
12. It has some unique features including the new Turnkey Module board With this board all the functional units of the computer the CPU RAM and PROM memory sense switches and serial I O can be contained on just two circuit boards which are supplied in the standard Turnkey version package But the most important advantage of the Turnkey Module is that it contains AUTO START which allows the computer to begin executing a program in PROM as soon as the power is turned on or the START is actuated The Turnkey Module includes the following functional parts AUTO START IK bytes each of RAM and PROM memory serial 1 0 Channel Control for the front panel Miscellaneous control and housekeeping logic The AUTO START feature is the key to the Turnkey version s ease of use When the power is turned on or when the START switch is actuated the computer is forced to begin executing the instruction at the memory location specified by switches on the Turnkey Module This means that when the power goes on the computer can be made ta start loader program or a monitor automatically without keying in a bootstrap loader from the front panel Alternately the computer can be made to start custom applications program at start up This should appeal to users who want to build the computing power of an Altair 8800b into a lab Instrument TWO machine tool or some other dedicated application The serial input output
13. 1 33 Represents line or column 2 etc This four byte sequence positions the cursor and the next byte received prints the desired character Notice that positioning the cursor beyond either field limit causes the cursor to disappear or scroll the display If the display is scrolled the program cannot blank the screen properly because the first home reference point will be lost The program is written in Altair BASIC with a user called Machine Language display routine at line 5000 Although if would be more efficient machine language its versatility would be greatly reduced in the translation The program accesses an Analog to Digital Converter card 88 ADC which reads eight channels of information and thus defines four points on the display fixed background field is also displayed By substituting another subroutine for the one at line 7100 Altair BASIC can plot any number of desired points simply by writing each point Into the Data Block which starts at location 8054 Be sure to limit memory size to 8000 when By Dave Antreasian ASCIIJ ASCII Octal Code Decimal Code 33 27 50 40 40 54 32 54 40 187 32 111 Inifializing BASIC Each point in the data block 15 specified by three parameters 1 the first byte 15 the line number ASCII 4 The second byte is the column number ASCII 3 The third byte is the desired character ASCII Notice that the data block Is composed of two s
14. 2 Z2 N 2EB F RMSKOTOMB EOC H2ZEQCHO M CH 482 X CUCHO HEATH IFPEBRGDHITDEJUGU EUBZSGO FORISKOTONN IPCIOEKO INEXT IFORISKOTONH T85KO FORJsSKOTONN THEN 1568 FORKzaOTONN 1FIPCRO KITHENRETURN IFIPCKORKITHEN 1558 IFABSCZCJ K ABSCT THENIRSJ ICSK TS8Z CJ K NEXIK IPCIC sIPCICO KI 3 IFIRSICTHEN 1598 FORLsKOTONH TSZCIR LOSZCIR LOSZ CICoLO 1ZCICLOSTINEXTL INMCI KBD 2SIREIINCI KI2 2IC iPVZZCICAICO ZCIC IC sKI FORL K TONNH ZCIC LOSZCICoLO PV HEXTL FORLISKOTONN 1IFLISICTHEN 1648 TEZC LIICOsSZCLIICOsHHB ZFORLsKOTONXNN NEATLI NEXTI FORI NNTOKOSTEPHM11FINCIX8 SINCIEIDOTHEN 1599 IRSINCIKB fICEINCIKI2 3 FORKEKOTONN 1T2 IR IC ZCK 1C TiNEXTK NEXTI IFPRAND2OABTHENGOSUB250g NVCN SKO81FORMEKOTONN sNUCNOSNVCNO EQCHM tHEXTM N IFPRAND255THENGOSUB24568 FO RMw wKEOTONB IBUCHMomEDO FORMSBKOTONN 2 BUCM 22 BV CM M 2 xNV CH IFPRANDKRZTHENGOSUB2T7800 FO RISKOTOHB BUCIO SBUCIO ECIOINEXT IFPRANDKATHENGOSUB2808 FORISKOTONB CUCIOSK CUCIOZYCIOXBUCID ACIO NEXTZ IFNDZKMTHEN 1798 FORIsSKSTOND Ls amp RWCIDILISCLCI IFBVCLIOTHENCUCLOSCUCLO DCIOX BUCLI HEXT IFPRANDSEISTHENGOSUB29B8S8 F ORISKOTONB CUCIJSCUCIOJO ACIO HEXT 5083308 FO RISKOTONBrCUCIQaCUCIOXxBUCID INEXT IFPRANDISTHENGOSURJ31Od8 FORISKOTONB BUCIJaBU
15. 6852 1977 27 1851 14 4 81752 26 3149 11 8728 2 26853 2 79423 2 79423 B B8427 17 2858 2 79423 8 88427 2 86763E 03 2 79423E 03 2 B86763E 03 2 79423E 83 4 4648 1E 023 40493398 T B8T7TTIE 83 8393823 TO RES IN BRANCH 1 SENSITIVITIES 1 27334 84 1 9325 04 TO RES IN BRANCH 2 SENSITIVITIES 02352651 8987287 0232357 TO RES IN BRANCH 3 SENSITIVITIES 0232213 0563955 48226419 TO RES IN BRANCH 4 SENSITIVITIES 9 97155E 85 9 48405E d4 2 42917 04 325596 2565958 2 79423E 03 7 34167 05 1 85865 065 C N June 1977 NODE VOLTAGES WITH RESPECT TO RES IN BRANCH 5 NODE HO PARTIALS SENSITIVITIES 1 14690551E 804 47757 04 3 2 38785E 04 1 19392 E 03 XER8UIV CURRENT NODE NO CURRENT 1 4 T519E 83 2 48814286 728571 NODE VOLTAGES WITH RESPECT TO RES BRANCH 6 NODE NO PARTIALS SENSITIVITIES 1 13134 06 1 25579 2 9 81382E 86 1 00245 83 3 1459331E 86 1 75858E 04 NODE VOLTAGES WITH RESPECT TO GM BRANCH 4 TO BRANCH 6 NODE NO PARTIALS SENSITIVITIES 1 4086827 5 BIIS2E 04 2 3 24105 4 63807E 03 57295 8 185E 04 NODE VOLTAGES VITH RESPECT TO VOLTAGE SOURCE IN BRANCH 1 NODE PARTIALS SENSITIVITIES 1 1 42635 03 2 85272 04 2 4985537 197727 3 2 80808876E 03 4 81T7T52E 84 NODE VOLTAGES WITH RESPECT TO VOLTAGE SOURCE IN BRANCH 2 NODE 0 PARTIALS SENSITIVITIES 1 4 13
16. Altair bus Ribbon cables and connectors complete the interface by connecting the printer to the computer via the interface board Check with MITS or your local dealer for prices and availability of the Q70 and C700 Altair 88 Q70 Specificiations Print speed and format 45 characters per second Full characters of electric type writer quality Forms Single sheets or continuous multipart forms with or without sprocket holes Maximum width of 15 inches SX MITS OFFERS TWO CRTs Font 96 character positions on daisy print wheel wide variety of fonts available in 10 and 12 pitch Prestige Elite comes with each unit Format Horizontally 132 characters and proportional spacing in increments of 1 120 Vertically spacing in increments of 1 48 up or down Slew rate at 5 per second Altair C700 Specifications Printing method Character serial impact bidirectional Printing rate 60 characters per second maximum 26 132 column lines per minute Transmission rate 75 000 characters per second bit parallel character serial Indicators Switches On Off Select Deselect Out Indicator Internal controls Automatic motor confrol paper run away inhibitor line feed after carriage return Paper feed Tractor pin feed up to 439 mm 17 3 Up to 5 forms can be handled Any sprocket fed continuous forms may be handled Dimensions 178
17. Aoproximately 300 bytes of the timesharing system June 1977 Typical Altair Timesharing BASIC system including Altair B 100 CATs Altair Floppy Diska and Altair 88006 Turnkey model Altair Timesharing BASIC supports up to eight users 1 0 Device Support A variety of input devices can be linked to Altair Timesharing BASIC and Altair Timesharing Disk BASIC This flexibility permits the use of CRT s for high speed data manipulations and Teletypes and hard copy terminals when hardcopy output is required Altair Timesharing Disk BASIC facilitates the listing of programs on a line printer Programs await listing in a queue to prevent mixing different jobs Users receive a message If the line printer is unavailable Versatile Program Storage and Loading Capabilities Altair Timesharing Disk BASIC provides rapid loading and program retrieval since all programs reside on floppy disk Read and modify passwords may be specified for program fixes to limit access by other users Altair Timesharing BASIC can be loaded from paper fape or audio cassette Programs may be stored for later use on paper tape Other Features Control of a specific job may be transferred from one terminal to another with a single command Varlous control characters allow suspension and resumption of each ob without loss of data Extensive diagnostics for program debugging Automatic line numbering Both versions of Altair T
18. FINAL NODE 8 Si iu n 2 B3 H 2 8 5 ae a east Ling Tae TR FOR OUTPUT GET NODE VOLTAGES for specified output AND BRANCH CURHENTS After solution and printout is PRINT complete the program returns fo the RUN EUH soe AM Input routine Several things are now possible END returns to BASIC SOLUTION du command level NEW restarts the NODE VOLTAGES program from the beginning and resets popes VOLTAGES all circuit values Since the solution does not alter any input data additional 18 m output be specified and another RUN BRANCH CURRENTSs made The print variable PR 15 reset to BRANCHES CURRENTS zero or output after each solution Each RUN produces only the output 3 2 2 2 requested for that RUN Modify THE CURRENT IN BRANCH 8 15 NEGATIVE The word MODIFY left OPPOSITE D SJERECTLON TO THAT RICH WAS ASSICHED increments the modify flag variable Data that changes component NOV MODIFY THE CIRCUIT FIG 3 values can then be entered Changing R THE VOLTAGE SOURCE IN BRANCH 1 IS NOW 12 VOLTS value to zero effectively removes the THE RESISTANCE IN BRANCH 3 IS NOW 11 OHMS component from the circuit New sources EET Un SAME OUTPUT can be entered in any established PRINT NV BC branch Mew branches cannot RUN entered MODIFY To modify a branch enter the letter voLT
19. Forty First St 918 664 4564 BEAVERTON OR 97005 8105 SW Nimbus Ave 503 644 2314 LINCOLN NB 68503 611 27th St Suite 9 402 474 2800 CHARLOTTE 28205 1808 E Independence Blvd 704 344 0242 ALBUQUERQUE NM 87110 3120 San Mateo gee BES B282 583 8283 ALBANY NY 12211 269 Osborne Road 518 459 6140 YORK 10018 55 West 39th Street 212 221 1404 DALLAS TX 75234 3208 Beltline Road Suite 206 214 241 4088 Metro 263 7638 HOUSTON TX 77036 5750 Drive 7135 780 8981 RICHMOND VA 23230 4503 West Broad St 804 335 5773 SPRINGFIELD VA 22150 66054 Backlick Road 703 569 1110 CHARLESTON W VA 25301 Municipal Parking Building Suite 304 345 1360 ees 2450 Alamo Se ASDC 3330 Peachtree Road Suite 343 Atlanta Georgia 30326 Albuquerque New Mexico B7106 Please send me a 1 year subscription to Computer Notes 8 20 00 per year overseas 5 00 per year in U NAME ADDRESS CITY m _ Check Enclosed L Master Charge BankAmericard Visa STATE ZIP MC or BAC Visa Jh Signature Have you written Software for your Altair Computer 3330 Peachtree Road Suite 343 The Altair 8800 computer was the first micro produced for the general public and remains number one in sales with more than 8 000 mainframes in the field
20. TZ2 Temporary variables ae Return flag for subroutine 600 MU Multiplier value LA Last value to be printed on this line PV current pivot Figure 2 initial node voltage final node voltage BY branch voltage element resistor voltage BC branch current element resistor current D dependent current source June 1977 Isolating problems in the Altair 680b 15 sometimes difficult due to the interaction between hardware and software The Altair 6806 may fail to operate for several reasons Bit 7 of location F002 might be high and the 6800 11 1 Figure 6 C N June 1977 New Troubleshooting Techniques Defined for Altair 680b Bruce would then jump 0000 Instead of outputting to the terminal Bad memory particularly in locations 00 3 00 can throw the MPU off the stack pointer is stored in one of these locations the 6800 can t access the proper instructions from the PROM monitor the 680b can go into a wild run condition Finally if the isn t initialized or working the 680b may output Troubleshooting procedures for these problems are covered in this article following a brief explanation of the Reset and Monitor operations during Reset The Baudot option monitor is not described here However those users with the Baudot option should be able to apply this information to their systems
21. be sub mitted oversize for reduction to format by C N All artwork should be mailed flat never folded Unless requested graphics are not returned Sketches roughs and idea drawings are generally not used Photos charts programs and figures should be clearly labelled and referred to by number within the text of the manuscript Only clear glossy black and white photos no Polaroid pictures will be accepted Photos should be taken with uniform lighting and sharp focus Program listings should be recorded with the darkest ribbon possible on blank white paper COMPUTER NOTES is published monthly by MITS Inc 2450 Alamo SE Albu querque NM 87106 505 243 7821 A free year s subscription is included with every purchase of an Altair computer Regular subscriptions can be ordered from the MITS Customer Service Dept for 5 per year in the U S and 20 per year for overseas Single copies are available for each at all Altair Computer Centers Entire contents copyright 1977 MITS Inc Send articles questions comments and suggestions to Editor COM PUTER NOTES MITS Inc MITS Inc 1977 Volume 3 Issue 1 June 2450 Alamo S E Albuquerque New Mexico 87106 NOTE Altair is a trademark of MITS Inc ALTAIR TIMESHARING BASIC CHALLENGES LARGE COMPUTER SYSTEMS By Susan B Dixon Altair Timesharing BASIC for microcomputers is a unique and dynamic package with powerful capabilities that challenge a field dominated
22. combination of articles written by knowledgeable free lancers and experienced MITS engineers designers and software specialists Whether you re currently a microcomputer expert or just taking those first scary steps into the jungle be sure to take COMPUTER NOTES with you You may need it 1 am a naw subscriber Please send ma ona year of Computer Notes 8 00 20 00 overseas enclosed have moved note my new address and extend my prasant subscription 65 00 20 00 overaens enclosed OD 1 have moved Please my nave address Old mailing label enclosed Print or type new adress on coupon TUCSON AZ 85711 4941 East 29th St 602 748 7363 BERKELEY CA 94710 1044 Universi 415 B45 53 SANTA CA 90401 820 Broadwa 213 451 0713 WINDSOR LOCKS CT 06096 63 South Main Street 203 627 0188 DENVER 80211 2839 44th Ave 303 458 5444 ATLANTA GA 30305 3330 Piedmont Road 404 231 1691 PARK RIDGE IL 60068 517 Talcott Road 312 823 2388 BURLINGTON 01803 120 Cambridge Street G17 272 8770 ANN ARBOR MI 48104 310 East Washington Streot 313 995 7516 MADISON HEIGHTS MI 48071 505 507 West 11 Mile St 313 545 2225 EAGAN 55122 3938 Beau D Rue Drive 512 HS 2567 ST pul D Pn M 8123 25 Bx EY 314 427 DAYTONM OH 45414 52502 North Dixie Drive 513 274 1149 TULSA 74135 110 The Annex 5345 East
23. examines location 092 Location FOO is the address of the hardware programmable bits i e terminal no terminal Baudot no Baudot etc The MPU stores this pattern from location F002 along with other information into locations OOFF If bit 7 terminal no terminal is high the MPU branches to location 0000 and starts execution If bit 7 is low the examines the number of stop bits indicated by location FOO and sends this Information to the ACIA When the ACIA is Ready to output the MPU then outputs the prompt character Troubleshooting 1 Halt the 6806 and examine location F002 Data bits 5 and amp should be high Data bits 1 2 3 4 and 7 should correspond to the hardware programmable straps set by the user Bit 1 will be low if the no Baudot option is set b Bit 2 will be low if 2 stop bits are set and high for 1 stop bit Bits 3 and 4 are not used and normally set low d Bit 7 will be low for terminal option and high for no terminal option If the data lights do not match the above list check for shorts and bad ICs IC RR should be enabled with a low pins 1 and 15 The inputs of IC RR correspond to the hardware straps If IC RR is not enabled X is usually at fault 2 Try the 6806 first in no terminal option with the following jump routine Jump 0000 ump 1 00 2 00 If the 680b fails to execute if properly examine all the locations in the PROM par
24. inverted at lines 1500 to 1690 changing Z to a nodal impedance matrix There are node resistances in matrix Z and equivalent node currents in matrix EQ The product NVzZ EQ 15 taken line 1700 setting the NV matrix to node voltages Ohm s Law Line 1720 takes the difference between initial and final node voltages and gives branch voltages in matrix BY Resistor element voltages are computed af line 1740 The source voltage is added to the branch voltage Resistor voltage is a voltage drop and source voltage is a voltage rise or negafive TWENTY NODAL IMPEDANCE MATRIX ROW COLS 1 1 3 B23 889 2 1 3 3163 61 3 1 3 818 31 NODE VOLTAGES NODES VOLTAGES 1 3 2 79423 BRANCH VOLTAGES BRANCHES VOLTAGES 1 4 11 8728 5 6 2 25853 ELEMENT VOLTAGES BRANCHES VOLTAGES 1 4 8 9272 5 56 2 26853 BRANCH CURRENT 5 BRANCHES CURRENTS ELEMENT BRANCHES CURRENTS 1 4 4 4636 03 5 56 4 53786 3 ELEMENT POWER LOSSES BRANCHES POWER LOSSES 1 4 398475 5 6 2102925 PARTIAL DERIVATIVES HODE VOLTAGES VITH RESPECT HODE NO PARTIALS 1 6 366T1E 06 2 4 41286 J 8 9663 06 NODE VOLTAGES RESPECT NODE 0 PARTIALS 1 2 9276 04 2 1 512981E 33 3 3J 487T27TBE 84 NODE VOLTAGES WITH RESPECT WO PARTIALS 1 2 321 3 083 2 D 53355E 03 d 2 26419E 803 NODE VOLTAGES WITH RESPECT NODE HO PARTIALS 1 2 84985E 05 2 2 70973E 34 3 6 945849E 85 2 85272 18
25. or prompt character if the 6800 microprocessor sees a transmit data register full indication by the ACIA status register The MPU may be continuously looping waiting for the ACIA to indicate that it is ready to transmit The program in Table 3 deposits the status in location 0020 since if cannot be checked when the 5806 isn t running Run the program for a moment then stop the 680b and examine location 0020 Data 1 should be high Indicating ready to transmit condition and data bit 0 should be low if data has been sent to the amp 80b Data bits 2 and 3 should be low If incorrect check to see if ACIA pins 23 and 24 are low which they should be If bif 1 Is low the ACIA was not reset properly Check the data lines from the 6600 to the ACIA for shorts or opens especially DO and 01 Recheck the signals to the Highs in bits 4 5 and 6 indicate transmission errors 6 the ACIA will output but not input run the program in Table 3 and check the status If the 680b keeps printing periods for proper letters typed to it like M or J then the ASCII codes for these letters are probably distorted The program in Table 4 can help isolate this problem While running the program type one character on the terminal Stop the 6806 and examine location 0020 Compare the bit pattern on the data lights to the ASCII code for that character If they do not match look for shorts on the data lines Pin 2 of the ACI
26. 12 Status Latch Drivers and Receivers Power On Clear Circuit The CPU board is in most respects identical to the 88006 CPU board described in a previous Computer Notes article see p 1 4 5 in July C N However the Power On Clear Circuit is especially important in the Turnkey version because if generates a pulse to reset the system The circuit is designed so that even short power outages generate a reliable Power On Clear pulse The Turnkey Module uses this pulse to reset the CPU by pulling PRESET low The CPU board extends this pulse to prevent the CPU from starting before the Paower On Clear pulse ALTAIR Required Hardware TIMESHARING The following hardware is needed to BASIC support both versions of Altair Timesharing BASIC CONTINUED Altair 8800 series mainframe and student Children find it particularly CPU fascinating use a computer to solve arithemetic problems Scientific and Engineering Uses Engineering firms and scientific labs minimum of 32K RAM Vector Interrupt Real Time Clock board Up to 4 2510 boards to interface currently using programmable calculators will benefit from the multi purpose capabilities of a microcomputer for complex math routines and statistical manipulation An Altair 8800 operating with Timesharing BASIC provides a number of individuals with access to graphic or tabular output in addition to the following mathematical functions SIN COS TAN LOG S
27. 2 528 PRINTINEXTIsPAINT PRINT RETURN PRINT PARINT EQUIV PRINTiFORI HATONN PRINTI KI EQCIO NEXTIS 1PRINT RETURN PRINT PRIMT 2NODAL IMPEDANCE MATRIXe G0TO2510 PRINT PRINT VOLTAGES PaRINT PRINT BRANCHES JOLTAGES 1LA KsLA KISLASLA KAfIFLA NBTHENLAZNB PRIHTz PRINTH4KI LA KI FORJeKTOLATPRINTBUCJD 4 3 IFHBA LATHENZT CONTINUED C N June 1977 CURRENT VECTOR amp 1PRINTIPRINT NODE NO CURRENT numbers in parenthesis The first branch number is the controlling branch The second is the branch in which the dependent source resides The next value is the transconductance beta value G defines transconductance and B defines current gain Assumed units are ohm mho volt and ampere The following multipliers are available kilohm Mz megohm millivolt and milliampere Numeric values can be in any form acceptable to BASIC s VAL function In many cases it s desirable to obtain a worst case analysis of a circult Circuit values are never absolute and vary in ranges i e 5 10 etc 50 the actual value installed in a circuit is unknown unless explicitly measured worst case analysis allows components with specified tolerance to vary during evaluation To obtain worst case analysis or standard deviation of node voltages tolerance values for one or more parameters should be entered They are entered as minimum maximum value
28. 43 2 45 43 43 42 42 4 4 42 eee 43 GLOCH DATA 45 DATA 255 END OF NINE SOFTWARE NOTES By John Hayes General Manager ASDC Program Improvement The Altair User Group is currently reviewing and improving the 300 programs in the User Group Library Many of the programs will be put in machine readable form and grouped for a particular size computer and language Single programs will still be distributed in whatever form they are recelved Current software listings printed every month in COMPUTER NOTES and supplied as a separate update sheet to all subscribers will show hardware and language requirements for each program When submitting a program users should indicate the computer 8800 or 680b the language used and the program s memory requirements in bytes Price Increase Rising costs of program duplication have resulted in a slight increase in prices for some programs Program and subroutine listings are now 4 for up to 10 pages 55 for 11 20 pages and 4 for 20 40 pages These new prices are indicated on the listings in this month s CN insert Price changes for all previous programs will be issued as an appendix ta the AUG Software Catalogue Machine readable code The User Group is interested in purchasing machine readable code for software programs already in the library Anyone who can provide the User Group with either paper fape or cassette forms of earlier
29. 7315 027463 527T269 185454 3 135852 8278193 NODE VOLTAGES WITH RESPECT TO VOLTAGE SOURCE IN BRANCH 4 NODE NO PARTIALS SENSITIVITIES 1 83860467 1 94033 4 2 59059 0154545 4945356 4 726 7 83 WORST CASE NODE VOLTAGES NODE NOMINAL CASE MIN i 2 79423 3 2886 2 31821 2 11 8728 15 1519 6 97497 3 2 26853 2 75874 1478153 S5TANDARD DEVIATION OF NODE VOLTAGES NODE NO STD DEV 1 0896619 555564 3 2863814 HORE TO DO 71 END C N June 1977 voltage drop This is reflected in Fig 1 by the source and resistor voltages that are opposite in polarity The branch voltage is the sum of the voltage drop in the branch or BV EV and EV BV Lines 1750 to 1780 compute branch currents in matrix CU by using Ohm s Law l E G to find the resistor current adding the dependent current source and subtracting the independent current source The independent current source is subtracted rather than added because is opposite In direction from the branch current By adding the independent current source back in at line 1800 resistor currents are computed in matrix CL Line 1810 computes the power lost in each resistor as the product of resistor current and voltage Line 1820 returns matrix BV to branch voltages Lines 1830 to 2240 compute partial derivatives of node voltages with respect to each circuit parameter They also compute a se
30. A should go low when the character is typed otherwise check 1 0 wiring If pin 2 of the is always low the ACIA will think itis always receiving a character Teletype is used as the 1 0 terminal it will run open Fin 2 could be low permanently due to shorts improper placement of components check R204 if TTY is used bad 1 0 CONTINUED components or if the ACIA is nof reset with software 7 Users with 680b B5M cards who are trying to check the write waveforms can use any program that continuously writes into memory The program is usually put in the working 1K RAM Table 5 contains a program that will write whatever is in location 0001 into an address of the 680b BS M card For further repair problems contact the MITS Repair Department INTRODUCTION TO MICRO COMPUTERS by Osborne and Associates and 6800 MICROCOM PUTER SYSTEM DESIGN DATA by Motorola are also excellent references on the operation of the 6800 and its family of chips Lege cre EA biH GEEL SNO ET ME I ium I aiei m n aie a sm um rmm 1 EFH n i a oe mem ida inam oL EL ncm as 1 n a urn n rez iem icem
31. AGES B and the branch number Omit the node group and enter the new values in NODES VOLTAGES this branch Component values that will 2 18 7 33333 not be changed can be omitted To modify a dependent source number omit the branch group and enter new BRANCHES CURRENTS transconductance or beta values If beta values are entered the resistance in the controlling branch should be changed BRANCH CURRENT 5 J 6656667 6656667 0556567 EIGHTEEN C N June 1877 MODIFY IT AGAIN TO BE FIG 4 T MODIFY T Bl Rs5 E 24 TR THE VOLTAGE SOURCE IN FIG 4 BRANCH 1 15 OPPOSITE IN POLARITY TO THE TR STANDARD BRANCH 1 7 B3 2 R26 TR INCLUDE BRANCH VOLTAGES IN THE OUTPUT T PRINT BC FORGOT SOME T PRINT HV BV T RUN MODIFY 2 amp NODE VOLTAGESs NODES VOLTAGES 1 58 2 15 8 BRANCH VOLTAGESx BRANCHES VOLTAGES 1 eg Ja 2 zz 15 3 BRANCHES CURRENTS 1 3 8 6 T R WANTED RESISTOR CURRENTS Too 7 PRINT 7 RUN MODIFY 2 ELEMENT CURRENTS BRANCHES CURRENTS 1 3 8 8 HOW ANALYZE THE SINGLE 5 COMMON EMITTER T R AMPLIFIER IN FIG 5 THE EQUIVALENT CIRCUIT IS SHOWN IN FIG 5 TR CAPICATORS HAVE BEEN REPLACED TR WITH OPEN CIRCUITS AND THE N657 TRANSISTOR WITH IT S EQUIVALENT THERE ARE THREE 5 51 BRANCHES AND ONE DEPENDENT SOURCE HAVE TO START OVER 1 NEW NODES 4 BRANCHES DEP SCS 3 ALTAI
32. CIO ECIO NEXTS IFCPRAND224 22KR8THENHI18 FORJSHOTOHNH zTzNVCJIOsWCJOmnTEWL JO2ST WHCJO2S2T 5DCJOSERO NEXT PUVSKIsFORITEKITOKA NUSNHB IIFIT K2THENIST7 IFMDaKMTHENZ22368 NUZzHD FORISKSTONU ONITGOTOI 918 1 18 1888 1988 IFECI sSKBH THEN2350 60701918 IFAC LIS HOTHENZ 350 FORJSKOTOMN NVCJ2sKBINEXTJs ONITGOTOI1928 1938 19480 1998 C N June 1977 2482 2508 2518 2528 2530 6 10 7 01 lt 1 3 11 1 1 2 TRS FNOSKMTHEN 1958 FORJ KaTONDsIFI lt gt CL JI THEN 1978 IIsRMWCJ TIS DCJO 1TR KA GOTO2888 HEXTJ 1121117 1 11 1 3 IFHICIIJaKMTHENNISHH KI G0TO2SOSO HIsNICII IFHFCII 2KHTHENNFSNHN K11GOTO2O8OAG NFSHFCII F RHEKSTONNs NUCH SNUCHO CZCHNIQ ZCNNFO2O amp T HEXTN ONTRGOTO2H6S3 29098 2188 1 978 IFNDSKATHENZ 100 FORJsKXOTONDzIFI CLCOJO THEN2893 HISRWGJO TIS YCIDQ DCJO W CECIIABUCIOQO TR2 K2 1GO0TO2080D NEXTJ IF PRAND32 KOTHEN2248 IFPVTHEZMPRINT PRINT PARTIAL DERIVATIVESx PVEKB PRINT PHINT NODE VOLTAGES WITH RESPECT TO 3 ONITGOTO2130 21490 2150 2169 em PRINT VOLTAGE SOURCE IN 1 1100702179 PRINT CURRENT SOURCE ACROSS BRANCH II K l PRINT ONITGOTO2IS8 2190 22080 2218 TI PC YCI GOTO2220 1 041 gt 60102228 TIsPC ECI2 GO0TO2228 TIsSPC ACI PRINT HODE NH0
33. GE June 1877 LIS DEMONS IRGALTOW OF RESEQUENCER PAOGHAKF tept 1 1 Az HEN 44923 TF 4 C GOSUumM 6249 1 27 49 OTT 6312 amp 1967 DAIAEND FOR NEXI et GO Oo rix SI One FRE AM HJN amp 3367 YD LTNE NEW 4 NULLS 2519419 5 LINES 7 EADY PUNCH REM DEMONSI TON OF KESEUJENGCEN FAOG AM eee TF J KEW IF 42C GOSUA GID 29 355 408 GISUS 241691349 6919 21 457558 ND CONTINUED Wi Z est Wx Y2 uY4xl PRINT IN STRIS THIRTEEN New Policy Adopted Due to rising costs MITS will now only accept orders for 25 or more Please place all other orders with your local dealer Hesequencer Program Keeps Lines Evenly incremented CONTINUED might find some assembled instruction with the same numeric value as the starting line number However haven t seen it happen yet and l ve used the program to resequence everything can find on a paper It usually takes only a few seconds to find the starting line number just a bit longer if the trigonometric functions are initialized in BASIC Even if the old first line number doesn t exist it will try its darndest to find it anyway I ve seen those lights blink f
34. KTTHENM U2 RETURN IsI4KItIFTTSK3ANDMIDSCXS I KI1 2 U THENB 3 IFTTEKAA AHDMIDSCOXZ I K13 A THEN 1800 HUnCI RETURN 1 1 1 gt 128 IF HIDSCXS I HKl s THENSOS 5 1 3 40951060 0128 FORKeKOTOII1 1FMIDS XS 1 41D PS KO amp K amp K1 KE THENNEXT G0TO 1088 PRSPRORCK2t PRINT SYUTAX PRINT RRANCH ERROR P05 1 END TOO GREAT END PRIMT NODE 4 TOO GREAT 1END TRY AGAIN GOTOISO PRIMT ZERO RESISTANCE CONDUCTANCE MOT ALLOVED EWND IFPRSH OT HEHPRINT HMO OUTPUT SPEGITIED s G0TO01939 PRIMT IPRINT PRINT PRINT IFMOTHEXNPRINT MODIFY UIMOJ e GO0TOI18590 PRINT s SOLUTION FO RKSADTONBIFORJSEKOTONN MCORJOSHKHINEXTJ K FORIsHOTONBiAIFHICIS ZHTHENHMCINICIADSKI gt 1939 lt NEAT FORISZHGTONNSZCINHAKIO2eRDB IZCHNAKl1 IO K FORJ amp eSHJTONNs ZCIJ 2sKB FORKSKSTOHBiTsSHCKIDITISMCHG JO 2 IFTuK2ORT le X8 THEM 1238 ds I IFHDaKMTHENIAGS 0 FORISEGTOHD ILSREUCIO MP5CLCIDOfFORJseKOTONN FORKeKOTONN LJ IFTSEDORTISKOTHEM1338 ECJKOnZCJAKO TSTISDCI NEATH sas I FORISRSTONSGrCUCT SHES CUCTIBACTI lt YCL ECL LAAG PORTSHOTON DI La tLisGLtl IFECLI THEHCUCL322CUCL DCIDO ECLI HEXT FORNSHOTONN
35. OR IZz1TO 16 IF MIDS 55 JZ 1 MIDS 525 IZ 1 THEM 50050 50040 NEXT IZ PRINT UNRECOGNIZED CHARACTER IN GOTO 50170 50050 ON IZ GOTO 50070 50290 50240 50220 50210 50270 50260 50300 50060 ON 12 8 GOTO 50200 50190 50280 50330 50120 50320 50150 RETURN 50070 FOR IZ JZ TO LEN IF MIDS 85 IZ 1 THEN 50090 50080 NEXT IZ PRINT MISSING IN GOTO 50170 50090 AZ VAL MIDS SSS JZ 1 0 50100 FOR KZ JZ TO IZ IF MIDS 55 KZ 1 THEN EZ VAL MID 55 KZ 1 50110 NEXT KZ JZ I2 RETURN 50120 1221 570796 SGNM EZ IF AZ THEN IZ ATMH L EZ AZ 50130 IF AZ 0 THEM IZ 1Z 6 283185 EZ 0 4 5 50140 AZ SQR AZ 2 EZ 2 EZ IZ RETURN 50150 GOSUB 50120 IF AZ THEN AZ LOG AZ RETURN 50160 PRINT LOG 0 OR DORO X Y X 0IN 50170 5 PRINT TAB JZ 1 50180 IF LZ THEN END ELSE JZ LEN S RETURN 50190 IZ AZ AZ BZ KZ EZ EZ FZ GOSUB 50230 DZzIZ HZ KZ RETURN 50200 IZ AZ AZS BZ 12 FZ IZ RETURN 50210 AZ AZ EZ EZ 50220 AZ BZJ AZ 50230 BZ CZ CZ DZ FZ zGZ GZ HZ RETURN 50240 PRINT AZ CHRS A3 LEZ 0 2 717 ABS EZ GOSUB 50120 50250 PRINT AZ AT EZ 57 295 78 DEG GOTO 50330 50280 GOSUB 50150 AZ AZ EZ EZ GOSUB 50320 50270 IZ Z AZ BZ EZ FZ EZ EZ BZ FAZ FZ 2 12 GOTO 50230 50280 EZ EZ 57 29578 GOTO 50330 50290 CZ CZ BZ 2 AZ HZGZ GZ F
36. PARTIALS SENSITIVITIES IPRINT FORNsKBTONN ABSCT I PRINTN K1 NUCN gt 4T 1INEXTN ONHITGOT02258 2268 2270 22B8B TIsC CIO YLCIDIAI CYCIO amp YLCIOO IT2S CYCIO YHCIDDO CYCIO THCI2D0 GOTO2250 TIzDHCIO DCID T25DLCI DCID2 GOTO2290 TISEHCIO ECID IT2SELCIO ECIDO GOTO2298 TIsAHCIO ACIDI1T29ALCI ACI TeTl T2 FORJ KOTONN 0NSGNCONVCJ K1G80T02328 2318 WHCJ 2WHCJO HVCJO amp T2 ULCJO S WLCJO 4NVCJO TI GOTO2320 WHCJ22 WHCJU NVCJOXSTISIWLCUJORVLCJO NVUCJ s T2 HEXTJ TeT amp T 56 FORJSK TONNs IFNVUCJ SKBTHENZ3AQ TINVCUJ215DCJ 85SDCJO TI TI T NEXTJ NEAT I HEXTIT IF CPRAHDGA 5KOTHENZAGB PRINT PRINT WORST CASE NODE VOLTAGES PRINT PRINT NODE NO0 NOMINAL MIN PRINT1FORJSKBT PRINTJ KIWCJ2 VHCJO WL CJ 1HEXT 1 PRINT1PRINT IF CPRAND123 2KOTHENPRINT PRINT GOTOI18 PRINT PRINT STANDARD DEVIATION OF NODE VOLTAGES PRINT PRIHT HO DE HO0 STD DEV PRINT FORISHKSTONN PRINTI K145Q0RCSDCIOQO NEXT PRINT 1 PRINT GOTOI18 PRINT PRINT NODE VOLTAGESs PRINHT PRINT NODES VOLTAGES PRINT LA KsLA Kl1LASLA KA IFLA NNTHENL A2NMN PRINTK K1 LA K1 1F RJ amp SKTOLA PRINTNVCJ 1INEXT1PRINTI IFNN LATHEN 46 PRIHT PRINT t RETURN PRINT PRINT sHODAL CONDUCTANCE MATRIX PRIHT PRINT ROW COLS s PRINT FORISKOTONN IFLA NNTHENHLASNN PRINT PRINTI K1 EeXI LA Kls1FORJSKTOLA PRINTZCI4JO IFNN LATHEN
37. QR SGN ABS INT and RND terminals no other types of 1 0 boards can be supported Line printer optional for Altair Timesharing Disk BASIC The following products are optional for Altair Timesharing BASIC loading and required for Altair Timesharing Disk BASIC An Altair floppy disk drive and controller B8 PROM board June 1977 15 completely removed from all and memory boards The mother board for the Turnkey version of the Altair 88006 computer has 18 usable slots Power Supply The power supply for the Turnkey version is the same as that for the standard Altair 88006 computer This power supply furnishes the following voltages at the indicated full load currents volts af 18 amps 18 volts at 2 amps 18 volts at 2 amps imt M N xw hu AM ALTAIH IVIINIDISK STORES OVER 71K The miniaturization of mass storage is just one of the exciting features of the new Altair Minidisk System Designed to work with the Altair 8800b the Minidisk has a storage capacity of over 71K bytes per diskette with an access time of less than three seconds Altair Minidisk BASIC resides in the lower 20K of memory and provides the disk utilization routines Altair Minidisk BASIC includes the standard functions of BASIC plus many extra file maintenance procedures that significantly increase programming power The software driver for the Minidisk Read Write functions is based on
38. R DC TR THIS TIME INCLUDE TOLERANCE VALUES FOR TR WORST CASE ANALYSIS AND STANDARD DEVIATION NCO 2 Rs2KCTX ESB8 CST T Be RKT Es28 19 21 7 B3 0 1 Re 100075 T 1 3 350104 7 BS H 3 2 508 465 535 T B6 HC2 3 LESC LOZ 01 B 4 6 50 10852 T PRINT ALL RUN SOLUTION xNODAL CONDUCTANCE MATRIX nnt 1 1 3 4 82381E 03 8 2 85714E 03 1 3 142857 5 9089 4 142947 1 3 145714 9 00981 85 147884 CONTINUED June 1977 M oo H ual first with the command if the resistance is changed at all Once the word MODIFY is entered only circuit modifications can be performed However they can be performed as many times as necessary If the ability to add branches to the circuit is necessary the program must be changed allow the modify flag be reset fo zero Subroutines are used for printing all output except partial derivatives worst case and standard deviation which are computed only If output Is requested General Program Description Lines 10 to 110 set up the program Function FNI minimizes its argument to zero avoiding a FC error in the DIM statements Three input statements get maximum nodes branches and dependent sources to accommodate different memory sizes To speed execution
39. S 1GO0TOICX33 270 HBsHB K1 G0T0318 269 IF MDTHEH TIHT DEP SOURCE TOO GREAT 71G0T01238 20 308 IsSI XI FORKSKITOK3 IFMID amp CXS I K1 MIDS CDS K KI THENHEXT COTOL0 288 ONXGO TO318 428 349 340 IFTYSsKITHEISSBO 43580 BGOSURSEJS TLsSTL HI1THeTH XK1s1FTL MBORTH MBTHEWIG 12 350 CL OUID STL IRWOMDO STH 3780 IsI KiiFORKSK2TOKS IFMIDSCXS I K12 MIDSCDS H1 THEHHEXT 0 28 LTFN nSTHEN 373 TT9 h HZ G02UBSIZ IFTTSRZTHEHA142 408 KsCL NDO ITS8TEYCKO TITLE YLCKO 1THsTH amp YHCKO 418 DCHDOETiDLCPDO2TLEDHCNUDOSTH GOTOL1283 426 IFTYaX2THEN 10928 38 GOSUDSOUSITLETL K12THs K 1 IFTL MNORTH MNTHEN 1825 IFTL2HHTHEXUN TL 1 460 MICDsTL NECUOmn TH ISIeKIfIFI LTHZNIDU AGU FOR KSTOKL i1IFMIDZQXS IKIO 4IDSCCS K KLl THENMWEZT 1G OTOLGOSG 448 Eg TT E KA COZUBSSIBIIPFISKSAMDCTT2REHIORTTSK2 THEN 518 T sEL T TISTL TLEKI TH THZzHKI T 1 528 YC ds TeTL XseTLs THCAISTH LFMO KSTHENN Y NY K1 538 GOTO4T 548 ECXOZTIELCX STL EHCX 8S8TH f IFM S KOTHENNE NE K 1 558 GOTOA7 568 ACKOSTIALCXOSTLEI AH CX STH IFMOS 1 578 GOTOAT7 600 ZZsHK2 GO0TOS5598 618 Zz sKl GO0TD05380 628 22 638 IsI KIf2529MIDSCXS I Kl1 fIFZ m ORZ 2 THENG 38 GOSUBT79O0 T5STI MU IFZZ K THENRETURN 650
40. The wide acceptance of the Altair computer and its rapid adaptation to many diversified appli cations has truly turned the dream of the affordable computer into a reality Yet the machine itself remarkable as it is repre sents only the beginning The right Software tailored to meet a user s specific requirements is vital part of any computer system MITS wants to insure that Altair users everywhere have the best applications software available today and in the future For this reason a new MITS subsidiary the ALTAIR SOFTWARE DISTRIBUTION COMPAN Y has been formed Its purpose to acquire the highest quality software possible and distribute it nationally through Altair Computer Centers That s where you come in The ASDC will pay substantial royalties to the originators of all soft ware accepted into the ASDC library If you have written business industrial or commercial use software for the Altair 8800 ASDC wants to hear from you It is the aim of the ASDC to stimulate and reward creativity in producing useful software that makes those dreams of computers for everyone come true The ASDC will select only software that measures up to its high standards for system design coding and documentation The software will then be further documented and distrib uted through Altair Computer Cen ters around 4 the country information on how to submit software to the ASDC ask your Local Altair Co
41. Z 2 2 RETURN 50300 BZ 0 AND FZ 0 AND AZ AZ 0 0 GOTO 50230 50310 GOSUB 50200 GOSUB 50150 GOSUB 50270 50320 50330 1 AZ COS EZ AZ SINCEZ 2 12 RETURN NOTE Spaces were inserted in this program listing to improve readability Deleting all unnecessary spaces will save 149 bytes This program was written in Extended BASIC It will run in 8K BASIC if line 50180 is replaced with 50180 IF LZ THEN END 50185 JZ LEN SS RETURN 30 user manual is avallable for 6 from the Altair User Group Software CONTINUED ELEVEN Hesequencer Program Keeps Lines Evenly Incremented Whenever write a program In BASIC the first few line numbers are always nicely incremented 10 20 30 etc The subroutines also start at easy to remember line numbers such as GOSUB 1000 But things don t seem to stay that nice forget put in a remark explaining what the routine is about and have to squeeze in 999R EM By the time the program is complete the line numbers look anything but well planned 10 16 17 33 49 The following resequencer program gives Altair 680 BASIC users professional looking evenly incremented lines The user choose the starting line number and the step of increment The BASIC resequencer program is only 33 lines long intentionally wrote in unusual line numbers To avold being a space gobbler the program lines are incremen
42. ble K When command 15 found has the bit number that needs to be set to one Two raised to the power K has the decimal equivalent needed in BASIC Using the OR operator to set the bits doesn t change any bits already set Setting the same bit more than once has no effect either Lines 1000 fo 1040 are error messages Error detection is limited and not recoverable except when an error occurs the beginning of the input line in a B or D number Lines 1100 10 1130 set up matrix M the nodal connectivity matrix It is set to zero Indicating which branches are connected with which nodes The values indicate 1 initial node 1 final node and 0 node not connected to branch If one node of a branch is ground no information is entered into matrix M Instead it is implied by the absence of one node Lines 1200 to 1290 set up matrix Z the nodal conductance matrix Z is a square matrix with dimensions max nodes 1 by max nodes 1 Its values are the conductance between the nodes indicated by the subscripts When the subscripts are the same values on the major diagonal give the conductance from the node to ground Lines 1300 to 1380 add transconductance values to matrix Z if there are any dependent current sources in the circuit Lines 1400 to 1430 compute the current for each branch in matrix CU Lines 1440 to 1450 produce matrix EQ M CU an equivalent current vector for each node Matrix Z is
43. branch Current in branch MB Nominal current source in branch MB Minimum Maximum by T Nominal voltage source in branch MB EL MB Minimum Maximum 7 D MB Nominal transconductance in branch DL MB Minimum d DH MB Maximum 5 a s EQ MN Equivalent current vector for node MN Counters for matrix inversion IN MN 1 Subscripts of matrix 2 showing Maximum values NV Node voltage of node BV MB Branch voltage of branch W MN Nominal node voltages Worst case minimum node voltages WH MN maximum RW MD Residing branch of dependent source CL MD Controlling branch of dependent current source SD MN Standard deviation of node voltages squared D K C P comparison characters for input KM R K1 K2 K3 K4 K5 K6 K7 K9 PC CT CM CI 86 constants Number of nodes in this curcuit NB A branches NY Y resistances ONCE ECRIRE in this curcuit HE woOoltage sources in this circuit NA independent current sources in this circuit PR output Flags X9 input line L Length of I Character pointer in X Loop variable J K L M H Ll IT II JJ loop variables TY Type of current input line X present branch or dependent source number T Temporary nominal vzlue TL n minimum TH maximum TT Type of current parameter HI HF Tl
44. by larger more costly computers Altair Timesharing BASIC and Altair Timesharing Disk BASIC are magnified versions of the powerful and efficient Altair Extended BASIC Each version Includes increased capabilities to accommodate as many as elght different programs running simultaneously and independently within the system Instantaneous Keyboard Response Input and output are interrupt driven and fully buffered to provide virtually instantaneous keyboard response even when the system supports the maximum number of users The output buffers empty more quickly than they are filled so it will appear the CPU is dedicated to each individual terminal High Speed Systematic Job Rotation Operating within a highly efficient round robin system the CPU suspends operation of job currently being executed stores the address of the next instruction and moves to the next job Each job is served a hundred milli second slice of 5 program Partitioned Memory Locations Established as a Fixed Partition System each job is confined to a unique area of memory Users may then access only their individual jobs not the system or other jobs This protects jobs from alteration or destruction The size of the memory area must be established with a minimum of 1024 bytes during initialization Memory areas may be of different sizes depending on need Each program area contains BASIC program text Variable and string space Work space
45. channel is essentially half of a 2510 board With the addition of a jumper selection the channel interface is compatible with TTY 5 232 or TTL signals This means that the Turnkey version can operate with almost any terminal or 1 0 arrangement with no Interface equipment necessary The 1 0 ports associated with the serial input output channel can be assigned to any 128 1 port pairs by switch selection The IK RAM and the PROM can each be assigned to any 1K block within the full Altair 88006 address space by switch selection The PROM used 15 the 1702 256 by 8 bit PROM disk bootstrap loader PROM a general purpose multi boot loader PROM and a small monitor PROM are also available from MITS for use with the Turnkey version The switches on the Turnkey version front panel are the POWER switch which has a key lock for system security START which Initializes the CPU and initiates the AUTO START sequence and RUN STOP which allows execution of a program to be stopped and started By Dar Scott again The indicators show that an 1 0 operation is in progress a HALT state has been entered interrupts are enabled or an interrupt is in progress The lights and switches provide the minimum facilities to monitor and control system operation CPU Board The CPU board is the standard Altair 8800b CPU board It consists of five major functional blocks B080A CPU Chip 8224 Clock Generator Chip 82
46. ections The first section bytes 8064 to 8075 is reserved for moving data points and the second section contains fixed points The sections are separated by a data byte 255 Upon recognition of the 255 code the display program jumps back to the BASIC program so the fixed fleld is displayed only once Then only the moving field is refreshed to the display This significantly reduces the display writing time C N June 1977 Machine Code Portion of Display Routine 037 100 41 101 bed 102 1037 103 315 Call Status 104 105 1037 106 175 107 133 110 424 111 023 Call Status 112 315 113 1 114 1037 115 076 116 11 120 121 122 123 124 315 Call Status CK 125 bed 126 1037 127 176 130 376 CPI test byte 131 377 132 310 133 323 134 023 135 043 136 003 137 076 140 003 141 271 142 302 143 124 144 i 145 315 Call Status 146 oer Cursor Address LXI B C 0 RET if Zero Output data INCR H L INCR B C 5 to C JNZ 147 L037 150 151 152 153 154 315 Call Status 155 166 Cursor 156 er Home 157 076 160 BA 161 323 167 023 163 303 164 pees 165 1057 166 333 167 022 170 027 171 037 172 522 173 166 174 1037 175 311 176 0 177 0 200 151 Data Loc 076 033 323 023 Next Data point Status Check Port 2 RS232 C N June 1977 50 60 TU
47. ed computer users Software articles such as games modifications and unique software systems make up the bulk of DDJ Product releases and reader responses round out this informative magazine COMPUTER MUSIC JOURNAL offers a comprehensive and highly technical approach to high quality musical applications of digital electronics This journal is best suited for those who utilize theoretical information for designing computer music systems Subscriptions and additional information about these publications can be obtained from People s Computer Company P O Box E Menlo Park 94025 SEVERN Graphics Display Adds Versatility to Altair System EIGHT The graphics capability of a CRT plays an important role in every computer system The graphics mode is especially useful for displaying graphs or curves quickly in real time and is a must for such computer games as Ping Pong The following program was written for these applications Although a hardware restriction limits its versatility the program 15 a helpful model for any system display The hardware restriction refers to cursor control incompatibility with terminals that include this feature This program was written for a Beehive 100 terminal in which the cursor 5 positioned by sending the following four byte code to the terminal Byte 1 Escape Sequence Code 2 Cursor Address Function Code 3 Line Number 4 Column Number 32 Represents line or column
48. f a maximum power dissipation of three watts and a maximum time of 350 nanoseconds Crystal controlled logic timing eliminates the need for on board one shot multivibrator circuitry This results in continuous operation without wait states for greater reliability Bus strips provide isolation between power and signal lines for maximum noise suppression Address selection is switch selectable in 4K blocks Each board requires one slot on the Altair 8800 bus C N June 1977 The Altair 100 CRT provides fast quiet and efficient operation far any Altair computer system Publications Offer i mcum i pim ERES ER Variety of Approaches The April issue of COMPUTER NOTES featured an article entitled Publications Provide Novice With Essential Information Page 10 May surveyed some of the current computer literature We regret that the following publications from People s Computer Company were not included C N June 1977 PEOPLE S COMPUTER COMPANY 15 a hardware software applications oriented tablold for the novice as well as the experienced computer user Information is presented in an informal style with many useful annotations PCC also acts as a sounding board for novel ideas proposing changes in computer technology The format of Dr DOBB S JOURNAL OF COMPUTER CALIS THENICS amp ORTHODONTIA is similar to that of PCC but information is aimed at advanc
49. ified by an input line 3218 PRINT PRINT BRANCHES CURRENTS 3820 PRINT containing the word PRINT lef 20 5 IFLA NBTHENLASNB justified followed by two letter PRINTK K1I LA X1 FORJ KTOLA PRINTCUC SNEXTJS PRINT 1FNS3 2LATHEN232 abbreviations for each desired value e 58 PRINT PRINTsRETURN See Table 1 The word ALL following 3123 PRINTIPRINT ELEMENT POWER LOSSESe PRINT PRINT BRANCHES POVER LO PRINT causes all output to be printed One variable PR is used to store the 7 to a value of one for one specific output a sraRTING WITH THE CIRCUIT IN FIG 2 type using the OR operator The bits of RUN PR are tested using the AND operator inier die when different output values pep scs g avallable Any number of PRINT lines can be used anywhere in the input ALTAIR DC ECAP The word RUM left justified starts the solution First a check is made to see if the minimum conditions for a solution have been met Line 130 checks for resistance or conductance in every THE NODES AND BRANCHES HAVE ALREADY BEEN NUMBERED 7 A BRANCH 1 HAS INITIAL NODE 0 GROUND 1 R AND FINAL NODE 1 NW 8 1 Regd 24 BHAMCH 2 HAS INITIAL NODE 2 AND FINAL NODE 1 B2 Nt2S1 Rea branch There must be at least one R BRANCH 3 HAS INITIAL 2 independent source at least one branch 7 R AND
50. ime Sharing BASIC furnish line oriented text editor with line and character manipulation capabilities Educational Applications single Altair 8800b loaded with either version of Timesharing BASIC can be utilized by several students performing independent operations One student practices program development another makes use of Timesharing BASIC s extensive diagnostics to debug a program while several other students calculate complicated equations All program activity occurs simultaneously with no discernable response delay Computer orlented education need not be limited to programming classes An Altair Timesharing System is a Valuable visual tool in science math and engineering classes and as an Introduction to the various aspects of computer technology to solve real world problems An Altair Timesharing System stimulates interest and provides a vehicle for discussion for the younger CONTINUED ONE Nevv Turnkey Version Features AUT O ST ART Those of you who have been asking for a Turnkey version of the Altair 8800b computer may now stand up and cheer because the Turnkey version of the mainframe of the 70757 is now avallable The Turnkey version incorporates ail the good quality construction and good looks of the Altair 88006 computer But just because the Turnkey doesn t have a front panel or a front panel interface board doesn t mean it s merely stripped down version of the Altair 8800b computer
51. ing Insulation displacement cables and connectors 1 0 Addresses Octal 010 011 012 Data Transfer Rate 1 byte every 64 us Data Format Hard Sectored 16 sectors Interrupt System Interrupt at beginning of sector Optional not used for Altair Minidisk BASIC Power Requirements 1 44 BV 88 MDDR Altair Minidisk Drive Description Disk drive case with power supply Buffer and Address electronics Includes interconnect Cable and one blank Minidiskette Specifications 1 Data Capacity Hard Sectored Forrnat Per Minidiskette 71 680 Data Bytes b Per Track 2 048 Data Bytes c Per Sector 128 Data Bytes FOLUR 2 Data Transfer Rate 125 000 Bits per second 3 Access Time a Disk Enable to READ or WRITE Function of motor start up time 1 sec min b Track to track 50 ms Average Access Time including motor start up time 1 85 sec 3 Worst Case Access Time 2 9 sec e Worst Case Latency 200 ms Functional Specifications l Rotational Speed 300 rpm 200 ms Rev 2 Track Density 48 tracks per inch 3 Number of Tracks 35 4 Number of Sectors 16 5 Time Per Sector 12 5 ms Software Altair Minidisk Extended BASIC Software on a Write Protected Minidiskette is virtually identical to Altair Disk BASIC in operation and features The manual includes Bootstrap Listing and READ WRITE Drive Code Be sure to specify the cassette tape or paper tape for B
52. m 4 puter Center for an ASDC Software Submittal Y or contact the ALTAIR WARE DISTRIBUTION COMPAN Y Packet SOFT subsidiary of ALTAIR SOFTWARE DISTRIBUTION 404 231 2308 Atlanta Georgia 30326 see next page a listing of Altair Computer Centers
53. mm high 457 mm deep 622 m m wide 7 x28 x24 5 Weight 27 kg 60 155 Electrical requirements 115 230 VAC T1055 50 60 Hz By Bennett Inkeles MITS now offers the 151 ADM 3 and the Altair B 100 CRT terminals for reliable communication in any Altair computer system Such user benefits as fast quiet operation and fewer mechanical problems are just some of the reasons to consider CRT implementation Both terminals display 24 lines of 80 characters non glare screen and interface at RS 232 and 20 mA current loop levels Each CRT includes the standard 64 ASCII character set and switch selectable transmission rates from 75 to 19 200 baud The LS ADM 3 and the Altair 100 also include many unique features suitable for a variety of system applications The ADM 3 s RS 232 extension connector permits interfacing to asynchronous serlal ASCII printers so that permanent copies can be easily retained The Altair 100 includes quad directional cursor control with carriage return and line feed an addressable cursor for direct positioning by line and column 11 numeric pad with decimal point for simple entry of numeric data erase mode for cursor to end of line and cursor to end of memory erase Altair 16K Memory Board Now Available The new Altair memory module provides 16 bytes of dynamic Random Access Memory By implementing low power and fast access dynamic memory ICs the Altair 88 15 runs a
54. nsitivity coefficient representing the change in node voltage for a one percent change in the parameter value Worst case node voltages are computed at lines 2240 to 2310 Lines 2240 to 2280 produce tolerance values with maximum tolerances being positive and minimum tolerances negative A worst case maximum value is computed as the sum of the products of partial derivatives and tolerance values when both terms are positive minimum value is the sum when both terms are negative Assuming that the partial derivatives are nearly constant over the tolerance range the worst case analysis is within about three percent of actual values In other words keeping tolerance values small 10 or less keeps the worst case analysis within three percent of actual values If larger tolerances need to be used or more accurate results are desired use direct substitution of minimum maxi mum values according to the sign of the partial derivative in a MODIFY and RUN again Be sure to repeat the procedure for each parameter The analysis used in this program has the advantage of giving results directly from the nominal solution CONTINUED TWENTY ONE Lines 2320 to 2330 compute a standard deviation of node voltages based on partial derivatives and tolerance values The sample solutions that follow were run on an Altair 88006 with 16K memory used Altair 8K BASIC versions 3 2 and 4 0 with some memory spare Processing an input line
55. of branch data requires about three to 10 seconds depending on the number of values The complete output in the sample run took about 15 minutes to print on a 110 baud terminal By using 4 0 BASIC input can easily be saved for large circuits Readers who are unfamiliar with electronic circuit analysis should look for a simple electrical engineering or network analysis text For more information applications read 1620 ELEC TRONIC CIRCUIT ANALYSIS PRO GRAM ECAP 1620 EE 02X USER S MANUAL publication number H20 0170 1 or IBM ELECTRONIC CIRCUIT ANALYSIS PROGRAM TECHNIQUES AMD APPLICATIONS Jenren and Lieberman Prentice Hall Inc Englewood Cliffs N J Table 1 Available Output NY Node voltages BV Branch voltages EV Element voltages Branch currents EC Element currents PL Element power losses PD Partial derivatives WC Worst case analysis 50 Standard deviation CM Nodal conductance matrix IM Modal impedance matrix CV Equivalent current vector ALL the above Figure 1 ECAP Standard Branch TWENTY Tyo Variable list MO Modify flag MN Maximum nodes MB Maximum branches MD Maximum dependent sources M MB MN Connectivity matrix NI MB Initial node of branch NF MB Final node of branch ME 7 1 1 Nodal conductance matrix Nodal impedance matrix Y MB Conductance in branch YL MB Minimum conductance in branch MB Maximum conductance in
56. on technique used is nodal analysis It s based Kirchoff s current law which says the algebraic sum of the currents leaving or entering a node is zero and Ohm s Law which says voltage equals the product of resistance and current Applying Kirchoff s current law Ohm s Law and some matrix alegbra a computer can find the solution of a circuit after a description of the circuit is in memory Circults are a series of nodes or places where fhings are connected together and branches or connections between the nodes containing electronic components Input of the circuit to the June 1977 program is in terms of these branches and their nodes The arrangement of each branch is standardized and assumed by the solution See Fig 1 Only the basic electronic components shown in Figure 1 are recognized by the solution Ohm s Law covers voltage current and resistance but says nothing about transistors diodes or 7400s Since only a steady state solution 15 found in this program capacitors are considered open circuits and inductors as short circuits However with the proper combination of the allowed elements shown in Figure 1 the user can model transistors diodes and other non linear components in a non steady state and non D C analyzer Every branch must contain one and only one non zero resistance or conductance According to Ohm s Law zero resistance requires an infinite current flowing in the branch
57. ootstrap Loader if required Programmed PROMS Available 545 each 1 MDBL PROM Minidisk Bootstrap Loader on programmable read only memory to be used with 88 PROM Memory Card at highest 256 byte block address 2 DRWT PROM Floppy and Minidisk READ WRITE Test PROM has the fundamental diagnostic tests for checking hardware operation To be used with the 88 at 3rd highest 256 byte block address ADD HARD COPY CAPABILITIES C M June 1977 TO YOUR SYSTEM Two New Altair Line Printers Available The Altair C7 OO calculates the most rapid way to print each lina eliminating unnecessary carriage returns and reducing wear Juna 1977 TUE MITS introduces two new peripheral products the C700 high speed printer and the Q70 printer to interface with the Altair 8800 series microcomputers The Altair C700 is a high speed serial character printer which prints up t 60 characters per second The printhead 15 a 5X7 dot matrix which prints the 64 character subset of the ASCII font The Altair Q70 is an upper and lower case electric typewriter quality printer specially designed and modified to interface with the Altair 8800 series It prints 96 upper and lower case characters and symbols at 45 characters per second 070 is ideal for business systems word processing systems or any other application which requires high quality printout for letters labels documents etc Each printer o
58. or a half hour and it still wouldn t give up Circuit Analysis Applications Expanded to Run with Altair BASIC By Tom Simpson An optional old starting line number further into a program will permit resequencing of a latter portion of the program This works as long as there is no previous reference to the earlier part of the program that is not being resequenced The user can increment the line numbers by any step even 3 2 or 9 7 GOTOs and GOSUBs are referenced correctly to line 437 13 Unfortunately Altair BASIC will not run a program with line numbers like that What can be done with such a listing you have a time share computer access at work give it to the time share coordinator Tell him or her Look what your time share has done to all my computer files now none of them run NXLLSTF URNSILOIT3 7CHAXECPO S tN EX 2CH amp S 1552 L 151 53967 a Ke EC 84 7 1 3972 Sta TA 6975 7974 6977 BAG TS amp 1q983 5397 41082 amp xOnA amp 19295 IRG 907 6399 3993 353 94 41245 43087 AEREE TAPUI 60 KUN IF ORE DATAGOSUB RETURNARENASIOP WATI CONI 2 CLEA d Da FN SPCC 1 EPS tera Fat
59. perates in a hlghly efficient yet unique manner The C700 calculates the most rapid way to print each line so That unnecessary carriage returns are eliminated The 070 operates with a daisy wheel system to rapidly print upper and lower case characters The wheel spins for character location and a hammer then forces the wheel against the ribbon paper and platen Both the C700 and Q70 provide other superior features for easy operation with minimal maintenance Each printer is furnished with form tractors to accommodate forms up to 15 inches in width An electronic Top of Form in the Q70 provides rapid positioning of each sheet A manual Top of Form switch Is also included With the 070 ribbon and or wheel replacement is an exasperating messy task The print wheel is easy to replace and the ribbon is conveniently enclosed in a cartridge CONTINUED FIVE New Products ADD HARD COPY CAPABILITIES TO YOUR SYSTEM CONTINUED When set to print less than 132 centered character lines the C700 has increased throughput since the print head returns to the right or left margin This special feature results in minimal wear since parts motion is reduced to an absolute minimum circuit which allows power to be decreased when the printer is inactive further reduces wear Both printers are easily integrated into any Altair 8800 computer system Each comes with its own special interface card which is plugged into the
60. programs should contact the Altair User Group Library Suite 343 3330 Peachtree Atlanta Georgia 30326 User s Program Handles Complex Numbers Complex numbers often appear in scientific and advanced mathematical calculation In order to use complex numbers the reader must first understand the concept of imaginary numbers An imaginary number is a real number multiplied with an imaginary operator The imaginary operator is usually represented by an 71 or FS This operator is defined so that the square root of minus one is equal to the operation i e 4 T i or i lorixi 1 Remember that the square root of a negative number is not usually defined With the above definitions the square roots of negative numbers can be 13 Notice that 3 9 and 3 9 But i3 9 and 3 9 Graph represents imaginary numbers should clarify the difference between imaginary numbers and real numbers Remember that it is possible to graphically represent a function in two dimension by drawing an x and y axis and then plotting values of the function 1 CX Y 2 2 2 X Y 4 3 3 X Y 2 2 4 CX Y 2 3 0 y 54 Y In this case both the X and Y axis are real number lines Now let s replace the real Y axis with an imaginary 1 axis so that the Y axis represents imaginary numbers represented For example 49 3 and7 4 4 5 4 3 By Chuck Ver
61. s or a percentage which follows the nominal value and enclosed in parenthesis Both types are shown in the sample runs By specifying a tolerance on one or key component values in the circuit the effect on the possible range can be determined on the desired output Numeric values must have some acceptable terminating character Since the input is into string and numeric values are extracted using VAL some means of finding the end of the number is needed to continue the scan of the input line The first method used was to compute the number of characters a number used on the input line using LEN STRS X X 9 However a number entered as 4 25E3 causes the expression above to evaluate to LEN 4250 1 4 or two less characters than 4 25E3 This method did not work for exponential numbers 50 decided upon another solution which allows use af exponential numbers and more flexible input This final solution uses numeric values immediately followed by some terminating character The characters space 5 K M and end of input line They are K and are frequently used in the input string SEVEN TEEN Solution and Output 2748 PRINT PRINT RETURN weive values are avallabla from ihe 2888 PRINT PRINT ELEMENT VOLTAGES GO0TO2718 eee 2022 PRINTIPRINT BRANCH CURRENTS G0TO3812 solution Any combination of output 3900 PRINT PRINT ELEMENT CURRENTS values be spec
62. s in location 0000 00 by depositing into each bit separately Locations OOF 2 D0FF used by the PROM monitor for various software bytes such as breakpoint address echo no echo and the stack pointer Make sure that these locations work and are separate from all other locations by lifting up each address switch one at a time and checking to see if only the corresponding LED lights If an LED does not light check for shorts For Information on deposit problems see Troubleshooting the 680b September CN 6 7 and 10 3 4 Unfortunately the status and data register can t be checked with the 6806 in the state because is low when the MPLI 15 halted If the ACIA is nof reset properly or given correct serial information the 6806 may not output the prompt character Check the inputs the ACIA for the halted state as listed in Table 1 Table 2 shows a program which initializes the ACIA and constantly outputs fhe Character whose ASCII code is in TWENTY FOUR location 000B This program is designed to be run when the 680b is strapped for no terminal so that the inputs which activate the ACIA can be seen Notice that if 41 is in location 0008 the letter U is output The ASCII bit pattern for the letter U is 01010101 resulting in an almost symmetrical square wave at pin 6 of the Any pulses or levels which do nof match Table 1 indicate a problem 5 The 6805 may never output the letter
63. t source Only component values included in the branch should be specified The only thing missing from Fig 1 is 4 dependent current sources which sometimes cause modeling difficulties dependent current source has a value which depends on a quantity in another branch of the circuit lina Dependent current sources are carried Internally as transconductance values Another often used value is current gain or beta value The values are related by the equation Transconductance beta resistance of controlling branch The problem is that if a beta value is used describe a dependent source then the resistance of the controlling branch must be previously defined Ofherwise a divide by zero error occurs when the expression above is evaluated 50 dependent sources are entered separately and only after all other branch has been entered Line 260 in the program does not let the user enter any more branch data after one or more dependent sources are entered The Input line for dependent sources follows the format branch data The first non space character is the letter followed by the dependent source number Nextis a branch group with the letter followed by two branch SIXTEEN PRINT FO0EJSITOL FORKTKITORKT IFMIDSCXESJ2KI 4 MIDSCKS K KIOTHEHNEXTH 4J I J El tHUSKI 1FZZ 2HlORK HGOORH KTTHENHRETURN TS 1 1 1 6 CT r RETURN IFTT K2AN DK
64. ted by one The last line 63999 User s Program is the largest possible line number that 680 BASIC will accept without displaying an error message How to Use the Resequencer Write or load your program containing the odd line numbers Then load the resequencer and type in the starting line 63967 After a few seconds the computer will ask OLD LINE NEW STEP NULLS Your answer might be 7 100 10 5 This indicates that 1 your old program began at line 7 2 you want to renumber it starting with line 100 3 in increments of and 4 set NULLS to 5 Resequencer does not rewrite program in memory Instead itf produces a typed listing properly sequenced to the users specifications With this listing and a punched tape the user can type NEW and then re enter the newly sequenced program Handles Complex Numbers CONTINUED START g HORE Y CHARACTERS T NEXT CEARACTERS X sono 5 TWELVE 5000 ERROR 560070 FOUND FINJ WITHIN PUT 7 D IMAG PART AT BOTTOM OF STACK existing line numbers into an array for By Doug Jones Sometimes the resequencer might be half way through a program and suddenly show an error message For example the newly sequenced listing might print the following message 240 IF THEN GOSUB ERROR ON LINE 473 OK
65. the hard sectoring format which simplifies system configuration The Altair 8800b interacts with the Altair system featuring Turnkey Modal dual Altair Minidisks LS ADNM 3 CRT and Line Printer June 1877 By Thomas Durston Minidisk Drive through two Minidisk Controller Cards that plug into the Altair Bus All control status and data 1 0 signals are handled through three 1 0 ports dedicated to the Minidisk Controller To insure maximum life of the drive motor a timer in the Controller turns the system off if the Minidisk is not accessed for five seconds The Minidisk Orive Case contains a disk drive power supply line buffers and addressing circuitry The Drive address is switch selectable The selected address is displayed on the front panel for easy identification Write protect is also a standard feature on the drive Check with MITS or your local dealer for prices and availability CONTINUED THREE NEW ALTAIR MINIDISK STORES OVER 71K CONTINUED 88 MDS Altair Minidisk Controller Descriptian Includes a set of 2 Controller Boards and Interconnect Cables Can control 1 to 4 Minidisk Drives Similar in circuitry and operation to the Altair Floppy Disk Controller First drive is included in AADS Additional Drives are available as B8 MDDR S Specifications Number of slots required in 8800 bus 2 Number of ICs TTL Logic 57 CMOS Voltage Regulators 2 Interconnect Wir
66. ticularly locations FFFF FFFE and FFD8 FFF4 The data in these locations should match the listing given in the System Monitor Manual If not do the following a Check address gating at pin 14 chip select for the Examining addresses from FFOO FFFF should result in a low at pin 14 When running only 0 amp should be lit CONTINUED TWENTY THREE New Troubleshooting Techniques b Check each address line on the PROM by separately lifting up 0 A7 and monitoring the PROM address pins If a line fails to go high with the address switch check for shorts Shorts between address lines can be found by trying combinations of addresses c Check the power and ground to the PROM Note that the 9v should be at east 9v at the bottom of the ripple d Check the data from the PROM and the data buffers WW and Y Y These buffers should be enabled e Chip select pin 13 of the 2102 RAMS should not be low for address FFOO FFFF f The MPU R W line should be high when the 680 is halted Check the halt state levels of the 6800 as shown in the following list ELO IMPL Ths un Speed 3 HALT Lona cbc l Rg ilei rigor ere L k raa Lib 4812 B bes ES write H hz 1 pes cher ire orc em BES rmi HIH 3 Make sure that working RAM memory exist
67. trees A complex number is defined as a number that has both real and imaginary parts It is usually represented in rectangular form as iB where 15 the real part and B is the imaginary part It is considered as one quantity when doing calculations For example the numbers 1 3 2 and 2 4 rerpesented In graph 2 28 op 522 3 34 i Graph 3 shows polar form as an alternative method of representing a complex number Notice that the point 4 4 can also be represented as a vector magnitude and angle which is written as L 3 3 the point 4 i4 In graph rectangular is represented as the length L from the origin at angle 89 where L 2X TY 32 4 and 4 4 or arctan 1 45 which is represented in Standard Polar Form as A C M June 1977 The following complex number flow chart and program written in Altair BASIC is available through the Altair User Group Software Library AUG Library number 7014 C N June 1877 Complex Number Intrepreter for BASIC Used as a Program or Subroutine By Dr John J Herro Annotated Program Listing main prgm subroutine bad char good char missing a L arith err error To drop stack T 49990 LZ 0 INPUT 55 GOSUB 50010 GOTO 49990 50000 17 1 50010 525 74 SIDRPEL IF S THEN RETURN 50020 FOR JZ 1 TO LEN 55 GOSUB 50030 NEXT JZ RETURN 50030 F
68. variables are used for constants Lines 120 to 570 process the input line R as the first character on the line causes the line to be ignored and can be used to insert remarks into the input Using an asterisk as the first character indicates that this line is a continuation of the previous line and causes a jump to the parameter extraction routine at line 470 The next non space character of continuation line must be R E or Dependent source input lines cannot be continued The processing of an input line is simple Look for B or D find its number check the number s range find the node or branch group check the numbers range and then extract parameter values putting them in the appropriate matrix Resistance is carried internally as conductance At line 510 minimum maximum resistance folerances become maximum minimum conductance tolerances The subroutine at line 600 controls extraction of numeric values It has three entry points at lines 600 610 and 620 to extract a single value B or D numbers two numbers in parenthesis node or branch group or both nominal and tolerance values Subrautine 790 to B90 extracts values finds their length on the input line and retrieves the multiplier if present The value is returned in and them multiplier value NINETEEN Lines 900 to 940 handle the PRINT input line Each two letter group is compared to allowed commands in P by loop varia

software notes - Altair 8800 Clone

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