a I B HARY OF THE U N IVLR5ITY Of ILLINOIS S\o. 8>a- cop. 2. Digitized by the Internet Archive in 2013 http://archive.org/details/designofprogramc154yama ).84 |54 DIGITAL COMPUTER LABORATORY >p 2 UNIVERSITY OF ILLINOIS URBANA, ILLINOIS REPORT NOo 15^ DESIGN OF THE PROGRAM- CONTROLLED SEMICONDUCTOR AND PRINTED CIRCUIT BOARD TEST CONSOLE by Shigeharu Yamada October 21, 1963 This work was supported in part "by the Atomic Energy Commission under Contract No, AT(ll-l)-10l8 «-* P * INTRODUCTION The design is given here of a test console which measures, under computer control, physical data on components and circuits, and transmits this data back to the controlling computer. This test console, in conjunction with a digital computer, can he used to design circuits or networks directly from empirical data, test previously designed circuits, and classify circuit components under given criteria. A test console of this type should prove helpful to circuit designers and computer fabricators. This paper consists of two parts: (l) system description, and (2) engineering design. 1. SYSTEM DESCRIPTION 1.1 A Brief View of the Test Console The Test Console was explicitly designed to he connected to ILLIAC II at the Digital Computer Laboratory; therefore, a word length of 52 bits was selected. All data are transported from ILLIAC II through an interplay channel to the Test Console and vice versa. Control information exchanged between the Test Console and the computer is indicated in Figs. l(a) and l(b). The machine is composed of three main units: Control Unit, Digital Readout Unit, and the Switch Group , The switch group interconnects the digital readout unit with test element and test register. It also specifies the connec- tion between this register and the voltage and current control networks . Data from the computer describing measurement items and measurement conditions are first read into the Buffer Register . This data is then transmitted to corresponding portions of the Relay Register upon receipt of a control signal decoded from the instruction part of input word. The contents of the Relay Register then dictate the connection mode of the switch group. These switches in turn specify measurement conditions and the input/output connection mode between the digital read scope and test unit. Other switches specify the external programming signal which controls the digital readout scope. Measured data from the digital readout scope is placed first in the Buffer Register. It is then read out on command from the main computer into a memory bank of the computer. Data can also be read into the Buffer Register and manually processed step by step. Push buttons are provided at the console for this purpose. This mode of operation is called "pseudo manual operation." Of course, if completely manual operation is desired, the test console need not be on-line to the computer. Input and output devices (typewriters, paper tape, etc.) are planned for ILLIAC III and therefore will be available at the test console. Therefore input and output data are fed to the ILLIAC II computer by means of these shared i/o devices . -1- CM Id cr < UJ < o 2 Q o UJ 0) UJ -J -1 f UJ -J O or < o. UJ < -2- TRAN G3 : TRANSMISSION GATE 3 TRAN Gl : " GATE I TRAN G2 : " GATE 2 FN FEEDBACK NETWORK DRS DIGITAL READOUT SCOPE S SWITCH NETWORK FROM BUFFER REG. 13 DECODER SWITCH FOR DRS CONTROL ~ CIRCUIT 1 h: RELAY REGISTER 13 13 13 TRAN G3 I MATRIX SW I MATRIX SW FN I PULSE SOURCE FN 1 VOLT SOURCE MATRIX SW 1 1 r r* 1 VOLT SOURCE •« UNDER TEST* DIGITAL READOUT SCOPE _ MANUAL INFORMATION _ FROM COMPUTER TRAN Gl BUFFER REG TRAN G2 TO RELAY REG «<- -►TO COMPUTER REGISTERS a DATA PATHS FOR TEST CONSOLE FIGURE I (b) -3- 1.2 Applications of the Test Console The machine is capable of all dc and transient measurements required for the selection of transistors, diodes, evaluation of basic printed-circuit board logic circuits (flipflops, etc.) and the development of memory systems. However, it would be necessary to supply additional circuits to evaluate magnetic thin-film circuitry. 1. 3 Word Format Prior to a detailed description of the operation of the Test Console, it is convenient to state the word format used. One word is split into four parts, each part containing 13 bits. The first 13-bit group indicates the measurement items and the instruction: measure, load, indicate zero error, etc. The second 13 bits are divided into three groups. The first three bits specify the terminal conditions at the emitter; the remaining two groups describe the units and the decimal point for base and collector terminal conditions The third and fourth 13-bit groups give the base terminal condition and collector terminal conditions respectively. If either the base or collector con- dition need not be specified, one loads the same condition into both the base terminal condition and the collector terminal condition. Word format is given in Fig . 2 , The item part specifies the appropriate connection mode between the digital readout scope and element to be tested. Connections specified are: 1) connection between the power supply and pulse generator feeding the test element. 2) input connection and channel selection to the digital readout scope (DRS). 3 ) external programming of the DRS, for example : AMPLITUDE, TIME, PERCENTAGE, SLOPE, MEASURE, and DIFFERENTIAL readout selection. k) connection between Relay Register and the Y and Y networks (shown in Fig. 7 and Fig, 9)« -K- Instruction Classification and hang-up 1 12 12 r-v-*- Item Group 1 B C Group 2 B Group 3 C Group h Figure 2 . Word Format Group 1: instruction (2 bits), item (9 bits), and classification (2 bits). Group 2: first 3 bits specify emitter terminal condition, 5 bits in B and C are for the units (3 bits) and decimal number (2 bits). Group 3: 12 bits indicate 3 decimal numbers of base terminal condition or, for the case of a logic test, the input circuit condition. Sign (1 bit). Group h: 12 bits indicate 3 decimal numbers of collector terminal condition, or, for the case of a logic test, the output circuit condition. Sign (1 bit). -5- 1.4 General Description of Operation Data flow between the test console and the computer is controlled by the computer program, as well as by auxiliary data supplied over the input device (e.g., typewriter). Once data is sent to the Test Console, it controls the operation of the console as discussed above. Operation of the console can be split into two operating cycles : a "setting cycle" and a "measuring cycle." In the setting cycle, all measurement conditions and connection mode settings are set up. In this machine, all condi- tion settings are carried out by digital feedback to insure high accuracy and stability. The flow diagram of this setting cycle is shown in Fig. 3° Upon completion of the setting cycle, the machine is ready to measure a specified item, load numbers into B and C of the Buffer Register read out the numerical voltage to ILLIAC II compare with the desired value if error I if no error add the error to the contents of Relay Register give no error signal to the Test Console Figure 3° Flow Diagram of the Setting Cycle -6- Before going into more detail., we give the function of all control signals in Table 1. TABLE 1. SEQUENCE CONTROL REGISTERS OF THE TEST CONSOLE AND RELATED CHANNEL CONTROL SIGNALS D FF S FF R FF s i FF S 2 DBY FF FF Channel FF Start/ St op FF SET BDI GO DBY SYNC SYNR J give sync signal to interplay channel control execute test console set cycle execute test console read cycle execute test console base condition set execute test console collector condition set tell the computer the test console is or is not ready to communicate tell the test console which channel is to be read out connected to the DBY FF and controls the transmission of information indicates that the channel is occupied indicates whether output or input to the computer signals transmit data synchronization of the successive data transmissions In actual practice the setting cycle has two loops } corresponding respectively to setting the base terminal condition (or input network conditions for logic circuit test) and to setting the collector terminal condition (or output network conditions for logic circuit test). For the emitter terminal condition, we do not use a closed loop conditioning control for reasons of economy, the emitter terminal condition is set by selecting one of the available built-in conditions. ■7- After these terminal conditions have been set, the Relay Register will keep these conditions constant during the measurement period, and the machine proceeds to the measurement cycle. (See Fig. k). At the end of the measurement cycle, ILLIAC II normally transmits the results to the I/O unit and proceeds to the next subprogram. However, the inter- play channel control progress will be interrupted by a "DBY" signal from the Test Console until the start/stop control sets BDY off. This situation is different for Mode 1 operation and Mode 2 operation: Operating Mode 1 (Multiple Measurement) In this mode measurement continues until finishing a specified number of measurement for each test piece. Operating Mode 2 (Single Measurement) In this mode only one type of measurement is assigned for each test piece. In both modes, the start/stop key resets the BDY flipflop: at the end of multiple measurement in Mode 1 or at the end of each measurement in Mode 2, Selection of Mode 1 and Mode 2 is determined by programming. After each measurement, if the control* signal is still on (i.e., Mode 1 operation), the machine is automatically ready to receive or give bits of information. If this signal is off, however, the machine is not ready to receive (give) information from (to) the computer until the start/stop key resets the DBY flipflop to off. This procedure provides for the time interval within which the test piece is being replaced by a new piece. Measurement control information and an appropriate program are loaded into the computer prior to the start of a measurement. After the data have been transferred to the machine, the set cycle operates as follows: data is decoded. If the data is a positive number, the machine proceeds to the setting of the given terminal condition. After the termination of the setting cycle (the setting cycle terminates when the machine receives the zero error signal from the computer), the Test Console initiates the measurement cycle, and then the readout cycle. Data takeout is controlled by the computer. ILLIAC II can transfer, if desired, the measured results to the output device. Also, a three range classi- fication can be read visually from colored indicator lights on the scope. Finally, the data can be statistically analyzed, etc., by the computer. *May be sent through special register, -8- load Relay Register (R, R. ) 1 read out condition \ yes no error? 1 no check S s S no load R. R. both f inished? (v r- yes read out data \ ILLIAC II Figure h. Flow Diagram of the Measuring Cycle 1,5 Manual Operation Manual operation is carried out by setting the MAN and COMP key to MAN. For manual operation: 1. Input signals are given by push-buttons at the console, 2. Output signal (measured data) is displayed on the digital readout scope. 3. Classification (low, ok, high) is displayed on the readout scope. k. Data measurement conditions are given to each E, B, and C section by three coded decimal digits, 5 . Readout : a. Digital number, unit, and decimal point specifying base setting conditions are read out into the B portion of the Buffer Register. b. Digital number, unit, and decimal point specifying collector setting conditions are read out into the C portion of the Buffer Register „ c. The measured data is read into the B and C portions of the Buffer Register, and transmitted from there to the high-speed register of the computer. In each setting cycle the measurement instruction with a revised input value (initial setting number plus error) must be loaded into the Buffer Register of the machine until the Zero Error signal is sent to the Test Console. Accordingly, each time S FF is set by the instruction. The Zero Error signal might be sent to the machine either through the special path from the computer or as data through the interplay information channel. In the present situation, Zero Error signal is indicated in the instruction part of the data from the interplay (instruction part is 00 in this case). The Zero Error signal resets the S flipflop, which indicates that the machine is in the base setting cycle, and therefore sets R FF. The setting cycle then proceeds automatically to the next setting cycle — if the S flipflop is in the set state. After R FF is set by the Zero Error signal) "DBY" changes to "l" to inform ILLIAC II that the machine is busy. When R FF is set, the gates GIR(c)G which connect the readout informa- tion to the collector portion in the Buffer Register are ready to transfer the readout data. At the Read Command signal from the control unit (following the Measurement End signal from the DRS), the measured data are transferred to the Buffer Register. After the completion of this data transfer, the R FF is reset by the Read End signal, and the DBY changes to "o" indicating that the device is not busy. The SET signal from Interplay resets DBY to "l, " and the measured data in the Buffer Register is transferred to the computer by opening the gate G2GC in conjunction with the BDI and GO signals from Interplay. ■10- 1.6 Channel Selection We have two output channels which must "be connected to the computer in the set cycle "because the setting error must be added to the contents of the Relay Register. This channel selection is accomplished by the machine automatically without any specific instruction. in the data from Interplay. The first readout in the set cycle always transfers data from the Buffer Register; the second readout in the set cycle always transfers the data from the Relay Register. Then the measured data is transferred from the Buffer Register. These two readout channels are controlled by the content of the channel FF, which changes state cyclically under control of the signal BDI f] SET„ The table of channel selection is as follows: Channel FF First readout in set cycle 1 Second readout in set cycle Data Read readout 1 First readout for manual operation If both S and S are zero, the channel FF does not change state, 1.7 Pseudo-Manual Operation In this operating mode all measurement conditions and measurement items are specified by pushing buttons on the console. Setting conditions are adjusted by the program to the correct value, and the measured data is displayed on the digital readout unit. The readout number is displayed until the reset occurs prior to proceeding to another measurement. The sequence is as follows: 1. Turn the MAN-COMP key to the MAN side 2. Push DATA button and ITEM button 3. Select E, B, C button k. Push SET button > conditions and items are loaded into the Buffer Register. DBY FF is set to "l." 5. Push READ button loads the Relay Register, connections between DRS and test piece are completed. 6. Operate START/STOP key DBY FF returns to "0"-- new control signals are transferred from computer to the test console. WIVEKSITY OF The program which allows communication between the machine and the computer must be loaded into the computer before proceeding to the measurement . The loaded program in the computer remains in the input state until the DBY FF turns to "O." Once the control signal is transferred to the machine, subsequent operation of the test console is the same as for automatic operation. Therefore, G1C is controlled by the S and S signal to allow information transfer from the computer, even in manual operation. This situation comes from the feedback control of the setting condition. The Channel FF is set to "l" by the MAN n READ signal from the console to read out information from the Relay Register. The READ button loads the instruction bit into the Buffer Register. G2R(B), G2R(c), and G2R allow informa- tion to transfer to the Relay Register from the Buffer Register. After the information has been transferred to the Relay Register, the Local Set End signal disconnects G2R. 1,8 Display Time Control When the R FF is set and Measure End signal is on (Pin GG on the rear of the 6R1 digital readout unit reads +20 volts when it is on), pin HH of the 6R1 is connected to ground. During the period in which HH is connected to ground, the 6R1 unit stores the measured data in its decade counter., Therefore, HH is connected to the ground by the signal R FF n GG, and disconnected by the Read End signal in ordinary operation. But in manual operation, the readout number is given by the display on the 6R1„ Therefore, until the operator recognizes the measured number on the display, the signal S n S f| M inhibits the decade counter reset until the next operation of the START/STOP key resets the R FF. 1.9 Successive Manual Operation In successive manual operation, the same measurement condition and the same measurement items are successively processed for each test piece. Therefore, the condition setting cycle need not be repeated after the first test, Only the START/ STOP key need be operated after inserting each new test piece. This is accomplished in the following way: Once the conditions are set up in the Buffer Register for the first test, the instruction bit in the -12- Relay Register is set to "l, " and the contents of the Relay Register are the same as the contents in the Buffer Register , Since the first readout is from the Relay Register, as described before, the measurement conditions are loaded into the memory of the computer. Then follows the setting program shown in Fig. 3- The instruction bit is not tested. Now, by the readout program, which follows the setting program, the contents of the Buffer Register are transferred to the computer and the instruction bit tested. All data from the Buffer Register has "0" in the instruction bit. Therefore, by the program in Fig, 5> the process does not go back to the loading program but goes instead to the measurement program- -unless the SET and READ buttons are operated again. load the conditions to M 1 I setting cycle I measurement process (readout) test the inst , bit or 1 if if 1 Figure 5 1,10 Manual Operation without Connection to the Computer For manual operations every step is executed manually. No communication occurs between the machine and the computer. The internal-external program control switch of the 6R1 unit is switched to the internal program side. All conditions and items are specified at the console. Automatic feedback control is not available as for ordinary measurements . Data push-buttons provide very close (+ one per cent ) control of the supply voltage and the pulse generator voltage without any external feedback device. The S FF and RTF are set automatically by pushing the ITEM and -13- SET and READ "buttons on the console. By pushing these buttons, the test piece is connected correctly to the input of the DRS, and the measurement conditions are stored in the Relay Register . The major difference between pseudo-manual operation and manual operation is the absence of feedback control in the latter case. Therefore all setting conditions must be controlled manually. Manual control is important in the present situation because the DRS cannot be programmed completely by an external program. All the controls of amplitude and of sweep velocity must be adjusted by watching waveforms on the scope. Therefore, the control of the units, that is, in amplitude, time, and mode selection of the sweep unit, is not programmable externally. These are important parameters for the condition setting because the comparison in the setting cycle must be made when the readout data and the given condition have similar units . Until the DRS can be programmed externally for the above parameters, we must check manually whether the readout data has the same unit as the given conditioning value. When measuring current, we must select the differential readout mode. The digital readout value is determined from the display on the sampling scope in every case, and if the display is over-scaled the digital read- out will not show the correct value. Hence, prior to automatic measurement, we must adjust the sweep velocity and amplitude on the scope to get a correct readout . These characteristics of DRS make it impractical at the present time to have a completely programmed operation, but the control circuits of the machine provide the possibility of complete external programming upon a future modification of the digital readout scope. 1.11 Automatic Operation This operation is the same as the psuedo-manual operation except for a difference in the condition setting procedure. (For pseudo manual operation, conditions are set manually. ) The operating program starts from the OUTPUT order to the Test Console All measurement conditions and items are specified by the computer program prior to the actual measurement. In the same way as for pseudo-manual operation -Ik- (shown in Fig. 5), the same kind of measurements can be made on the successive test pieces by merely operating the START/STOP key at the beginning of each measurement. To change measurement items, one replaces the former item by requesting new items through the input device (typewriter, etc.), or, as in the case of pseudo-manual operation, feeding the new item into the Buffer Register. The second mode of operation, which allows successive measurements for each test piece, is carried out as follows : 1) Load a list of the successive measurement items into the memory M, in the computer; 2) Set the number N (the numbers of measurements) in a special counter in the computer and proceed with the following program (Fig. 6): load the machine by the content of M-, I setting cycle read out from the machine into the memory Mo -^ I/O printout subtract one from the counter if > 4 lf = m ~ \ add one to the output address Reset the output address Figure 6 *The same kind of control gate signal described o'. page 8. •15- In the Test Console if GO from the Interplay changes (turns to "0"), the DBY FF is reset at once, but after a short delay this again is set, and remains in this state until the next operation of the START/ STOP key. Readout data is stored in the memory of the computer and used in the following applications: 1. data analysis and other programming. 2. transferred to the output device(s) and printed out. 3. compared with a reference value table for classification, and the Test Console informed of the classified level by the special bit (10th, 11th, 12th bit), or this classification printed out with the data. ■16- 2. ENGINEERING DESIGN 2.1 Basic Units of the Test Console There are six basic units in this machine. They are : 1. Control networks for the power supplies and pulse generators 2. Control networks for external programming of the Digital Readout Scope (DRS). 3. Console registers. k. Buffer and Relay Registers. 5. Control and decoding circuits of the machine sequence control. 6. Cable drivers and terminators of the ILLIAC Il/Test Console interplay channel. 2 . 2 Control Networks ( Y ) for Supply Voltage Selection All control of supply sources is accomplished digitally by means of the Relay Register and the Relay Networks. The Relay Networks are shown in Fig. 7; each contact a. is shunted by a resistor. These resistors are arranged to give three coded decimal numbers . The constant current through the remote sensing resistance of the Kepco power supply is adjusted at 1 ma for the dc supply voltage and slow pulse generator, and is adjusted at 2 ma for the fast pulse generator. Either the I slow pulse generator or the fast pulse generator is connected to the base terminal, depending on whether it is a time measurement or a dc measurement. When the fast pulse generator is connected, the resistance value of the control circuit of Kepco supply is changed by the relay to give a more sensitive control (normal sensitivity is 1 volt/Kfi) and a high output voltage (in fact, of twice the magnitude because the pulse out of the type 110 pulse generator is exactly one-half of the external supply voltage). 2.3 Unit Selection and Decimal Value Control Units and decimal value for base and collector terminal conditions are given in one quarter word and transmitted to the machine either manually or by -17- o 9 sections total T mv 4 T ii 11 V / d 2 A A A / d i / d ^ > 2-10"^ > 2 - 10" < p2'10"J > aD0 <> 20 > II II mv T f it. it V / d 2 A / d / d 2 / d l / ^lO" 1 A.0" 2 To load a resistance value, push buttons "L" and "Set" (manually ), or give "LOAD" (automatic). The instruction "LOAD" is also used when loading the input circuit (Fig. 10 ) and output circuit (Fig. 11 ) for logic circuit tests. TABLE 5 1 Load Load the input and output circuit, load the resistance value. Value is given in the RIO. 1 Measure Measurement condition is given in the Relay Register. Zero Error 1 1 Classify 2 .5 Measurement Item Selection Measurement items that can be selected have been chosen temporarily as follows : 2„5°1 Time Measurement Transistor Diode storage time delay time buildup time fall time recovery time buildup time ■21- -22- - Ul X 0> MS L-0 ©J GH o a a. 3 _j <2 < u. a ^Dr" i »— o I- o z Z o o -23- -* — T— *B -©- -@ ii Q9 ♦- ii — e — r- n — 09 — ♦- -@- 3- K ,K|, K 7 ARE EACH COMPOSED OF ONE A TYPE AND ONE B TYPE RELAY RIO. DRIVER +V -®~ *0 ~© K 3- "® «4- -<£) *5- -® K 6 - "® K 7" LOADING THE INPUT CIRCUIT FIGURE 10 -2k- + 12 <2> o — \4 — >► o — 14 — <£> <£> <£> <£> <2> <2> "I K 2 K 3 K 4 K 5 K 6 K, + V LOADING THE OUTPUT CIRCUIT FIGURE II. -25- 2.5.2 dc (Slow Pulse) Measurement Transistor I CBO """EBO ^E CEO V CE(sat) CER CBO BE V CE V. EBO Diode leakage current "breakdown voltage forward voltage 2 .6 Logic Board Measurement Logic board measurements are carried out by the same measurement method used to specify the load resistance value. First the LOAD instruction and then the MEASURE instruction is given. Items specified in the Buffer Register are decoded. The decoder output drives a matrix circuit to operate relay contacts: the connection between the DRS, the test piece and supply source (Fig. 12); the per cent network (Fig. 13 ) and finally the relay network for external programming of the DRS. 2 .7 External Programming of the DRS For external control of the DRS, selections executed by sensitive reed relays are shown in Table 6. Connections are changed according to the machine operating cycle. -26- o o > > )m ~ / w / V) U- / cd/ CD O N CVJ a: o UJ a. o o CO LU o EADO SOUF 0£ „ >- ITAL UPPL O CO CVJ °Q LU u < a: O UJ . . U- h uj ui — CD 0- O LU h- h- O UJ 2 Z o o -27- 0% o- 00%o- 0% o I00%o X R 2 > A. "s* R 4 ^ R 5 i R c } T R 2 <> R 3 | R 4 < R5 I Re i =2<^+ -0^0- -0^0- !©"&- -OA% START ■°n< 7^v< o-^ T^^ r°^ C O-o -r^ - 10% R, = 12.5 K 20% R 2 = 12.5 K 50% R 3 = 37.5 K 70% R 4 * 50.5 K -oA% STOP NORMALLY OPEN RELAY 125.0 K (TOTAL) R 5 = TRM = 12.5 K B °W B, ■o-"b- B ; B 3 o^b- B 4 o-*o- B 5 O^Or ■o B% START B ^ B' *s! B ^v< B -o^c B 7<^°- ■o B% STOP PERCENTAGE OF Y NETWORK SELECTION FIGURE 13. -28- TABLE 6. MEASUREMENT SELECTIONS AVAILABLE AT THE DRS K i h K 3 K, 5 K K 6 «1 time measurement or amplitude measurement selection starting channel A or B starting slope + or - select first slope or second slope these are the stopping controls corresponding to IC, IC, K. respectively 2.8 Information Loading and Readout Push-button information is first fed to encoding circuits and then connected to the Buffer Register. Readout data (three decimal numbers, units of measure, and the position of the decimal point) are also fed to the same kind of encoding circuit, and transferred to the Buffer Register (Fig. lk). Units from the GR1 are M, N, u, V, S on pins Y, Z, AA, BB, and CC respectively, and the unit push buttons on the console are Qy, Gv^ 00 > GO and (kfi) respectively. Units from the 6R1 and the push buttonsare decoded prior to feeding them to the encoder. These are: V = BB + (?), MV = Y n BB + n MA = (M) n 0, ua = n msec = Y n CC, usee = AA n CC, nsec = Z n CC YSl = . The Read command gate actually takes out data from the 6R1 unit (see Fig. 15). The gate G1RG feeds the readout data to the encoder. The momentarily operated push button "SET" transfers the push button information to the encoder. G1M (B) (c) and G1R (B) (C) are the gate signals to transfer manual information and readout information respectively to the Buffer Register, G1M (B) (C) (E) are,, simply generated by the circuit in Fig. 16. -29- ruWin CO o I 3 + O u. -o^o > + -30- nroTL 0000000000 -J2zQ-a:coh-3>^ X >~ N O ja O TJ I00-^ >5.6K>t t -5 * + 25 NOTE: ALL RESISTORS 5% TOLERANCE CABLE TERMINATOR (AT ILLIAC 11 ) FIGURE 19 -35- PCB**iOI8-l35 +6 PCB*I0I8-I24-0I PCB*I0I8H23 I Tf-255 IN 2K-A. TI-25'5 +6 TI-51 5.1 K-^. J9I-A. OUT 2N967 I -6 NOTE: ALL RESISTORS 5% TOLERANCE CABLE DRIVER (AT TEST CONSOLE) FIGURE 20 + 12 IN o PCB#I0I8-I22-0I I00-a.SI.6K-a. -6 +|2 NOTE: ALL RESISTORS 5% TOLERANCE CABLE TERMINATOR (AT TEST CONSOLE) FIGURE 21 ■36- +6 <2K-^ PCB*I0I8HI4 T 1-255 -M — o- IN O 44 44 44 44 44 44 TI-51 20K^l NOTE: ALL RESISTORS 5% TOLERANCE 1 +6 2 N 706A^ -6 NAND FIGURE 22 PCB#I0I8-II4 IN TI-255 O * o- IN 750 + 6 10 K-^S 2N706A -6 NOTE: ALL RESISTORS 5% TOLERANCE NOR FIGURE 23 ■37- OJ I 00 o # CD O DL 40 I -6 NOTE: ALL RESISTORS 5% TOLERANCE AND GATE DRIVER FIGURE 25 -39- 2.13 Digital Readout Scope The Tektronix Type 567 digital readout scope is the principal component of the digital readout in the machine. Measurement accuracy of the scope is ordinarily + 3 per cent for both time and amplitude measurements. The least-significant digit can be ambiguous also. Minimum value of the input signal is 2 mv; minimum measureable time interval is 0.4 nsec . 2 .1*4- Power Supply and Pulse Generator A Tektronix Type 110 pulse generator is employed for time measurement. This pulse generator gives a h nsec rise and fall time, and 'a., pulse width of up to 100 nsec with the voltage limited to one-half of the external power supply voltage . The Tektronix Type l6l pulse generator, for dc measurements, gives 1 usee rise and fall time and up to 1 msec pulse width. Output of this pulse generator is fed into a transistor stage. The output pulse voltage is equal to the supply voltage. A Kepco power supply, suitably modified by a relay network (called Y ), controls both the fast and slow pulse amplitude, as discussed previously. All resistances in the Y and Y networks have + 2 per cent tolerance. v — * -ko-