SU938221A1 - Multi-function logic probe - Google Patents

Description

The invention relates to a discrete technique, and more specifically to devices controlling its parameters. A known probe for testing digital logic circuits, comprising a comparator and indicators of the logical circuit state tl. Its disadvantage is that this device has limited functionality; the static state logic state indication node, which is included in its structure, does not allow distinguishing three basic states of a static logic circuit: logical O, logical 1, failure. The closest in technical essence to the present invention is to diagnose the technical state of discrete devices, comprising a static circuit diagnostics block, a dynamic circuit logic diagnostics block including a pulse counter and a display unit connected to the pulse counter. This device allows to distinguish the state of a logical circuit in eleven gradations, which limits its functionality. The device is very complicated, because, in addition to the three main states of the static logic circuit, it implements the functions of recognizing dynamic processes occurring in the logical circuit: the recognition of differences, polarities of single and pulse packs G2. The complexity of the device determines their significant energy consumption, which requires the use of an autonomous power source, and all this increases the size and inconvenience of the device. The purpose of the invention is to miniaturize and extend the functionality of the probe.

The goal is achieved by the fact that a multi-functional logic probe 8 containing a static circuit diagnostics unit and a dynamic state diagnostics block of a logical circuit, including a pulse counter and a display unit connected to the pulse counter, has a gating node inserted into the dynamic circuit diagnostic unit. , and the diagnostics unit of the static logic circuit is made in the form of a controlled pulse generator and a light indicator, moreover, the controlled generator and The pulses consist of four series-connected logical inverters, a capacitor is connected between the outputs of the first and second of KOtopbix, and a voltage divider is connected between the common bus and the output of the third inverter, consisting of two series-connected resistors, the middle point of which is connected to the input of the first inverter and through the isolation resistor is connected to the first input of the probe, and the light indicator consists of two LEDs of different colors, one of which is connected via the first current limiting resistor with the output of the third inverter controlled pulse generator and the other through a second current limiting resistor connected to the output of the fourth inverter and the first output of the probe.

In addition, the gating node contains four 2I-NOT elements, two inverters, two control flip-flops and a reset element, which is a microswitch, with the second probe input connected to the input of the first 2I-HE element, the output of which is connected to the counter counting input. which is connected to the installation input of the first control trigger and the output of the second element 2I-NOT, the first input of which is connected to the direct output of the second control trigger, the second input is connected to the output of the third element 2I-NOT, and The secondary input of the second trigger is connected to the third input of the probe, the reset element and the first input of the third element 2I-NOT, and the counting input of the second control trigger is connected to the output of the first inverter and the control inputs of the first and fourth elements 2I-NOT, the input of the fourth element 2I-NOT connected

To the fourth input of the probe, and the output to the counting input of the first control trigger, the output of which through the first inverter is connected to the second input of the third element .2 AND-NOT, the output of which is connected to the second input of the second element 2I-NOT, and the second inverter is connected between the output of the higher order yes counter and the second output of the probe.

FIG. 1 is a block diagram of a multifunctional logic probe; in fig. 2 - schematic diagram of the probe.

The multi-functional logic probe (Fig. 1) consists of a static logic circuit diagnostics unit 1 and a circuit dynamic diagnostics unit 2, in which the counter of 3 pulses is loaded by the display node k, and the inputs of the counter of 3 pulses are connected to the gating unit 5. Unit 1 consists of a controlled generator of 6 pulses and a light indicator 7. A controlled generator of 6 pulses of 1fig. 2) consists of four inverters 8-11, a capacitor 12 and a voltage divider, consisting of resistors 13 and 1. The decoupling resistor 15, is connected to the midpoint of the voltage divider, through which with a probe at input 16 the probe is connected to a static logic circuit under investigation. The light indicator 7 consists of LEDs 17 and 18 of different colors for the current limiting resistors 19 and 20. The output of the inverter 11 is connected to the output 21 of the probe. Gating node 5 contains four elements 2I-HE 2225, two inverters 26 and 27, two trig. Controllers 28 and 29, contact 30, input probes (inputs) 31, 32 and 33, output probe 3 (output) and strobe indicator 35 (LED).

The probe can be performed on integrated circuits of widespread series (133, 136, 155, etc.).

The probe works as follows.

Claims (2)

To study static logic circuits, a controlled pulse generator 6 is used, which, in the absence of a signal at input 16 or in the presence of a signal whose level is higher than logical O and below logical 1, produces a pulse pattern of the type. The values of the resistors 13, 1 and 15 are selected in such a way that when an input at the input 1b of the logical 0 or logical 1 oscillations of the generator 6 are disrupted and one of the diodes 1 or 18 is lit, respectively. To influence the unused inputs of the logical circuit being investigated, output 21 is used, which, with a corresponding signal at input 16, can be applied to the circuit under study O, logical 1 and impulse voltage. A pulse counter 3 with a 5-node node is reset to the initial state by short-circuiting the contact 30. At this, the control trigger 29 is set to one state, and 28 control and the counter 3 pulses are in the zero state. If after that, pulses will be received at input 3, they will be calculated by a 3-pulse counter (simple pulse counting mode). The display node indicates by the LEDs the number of pulses that have passed to the input 31 for the investigated period of time in binary code. If there is a positive pulse or a single transition from logical O to logical 1 at the input 33, a sharp-pointed impulse is formed in the circuit formed by control trigger 28 and inverter 2b, which sets the counter 3 impulses and control triggers 28 and 29, then the count continues pulses arriving at the input 31. Upon the arrival of a second positive pulse or a positive differential at the input 33, the control trigger 28 is set to 1. In this case, the elements 2I-NO 22 and 25 are closed at the control inputs. Thus, in the counter 3 pulses will be recorded the number of pulses arriving at input 31 between two positive pulses arriving at input 33 after opening contact 30. The fact that the gate 5 is triggered is indicated by an LED 35 Inverter 27, output 3 and input 32 are used when several probes are connected in series to increase the number counter bits. Thus, a multifunctional logic probe allows to check the state of a static logic circuit, excitement of the studied circuits by a pulse sequence, or static equations of logic O and 1, counting the number of pulses, including single detection, counting the number of pulses arriving at input 31 in the interval between two pulses arriving at input 3.3 after the termination of the Reset signal. The multifunctional logic probe also allows determining the sequence of two single pulse arrivals to inputs 31 and 33, approximate determination of the period frequency) of the pulses fed to input 31 (33 using its own pulse generator by connecting the output-inputs 21 and 33 O1. The measurement range can be expanded, and accuracy is improved when using an external pulse generator (for example, from a tunable device), and two probes connected in series (output 3 of the first united with input 31 of the second, inputs 32 are combined, gating pulses are fed to the first probe adapter 33, determining the operability of logic elements (inverters, flip-flops, counters. At the same time, the inputs of the monitored elements are excited through the output 21 of the probe, the output state is controlled by the input 31 of the same probe, or the input 16 of another. The functions listed do not limit the capabilities of the multifunctional logic probe, its equipment can also be used for other more specific operations. atsiyatsii (for example, to control pulse frequency dividers, decrease the pulse frequency, etc.). A large number of operations that are common for setting up logic devices and implemented using a multifunctional logic probe, determine if it is used. use of resource saving expensive universal measuring devices, low cost of work., miniature, determines the ease of use and the ability to use where the use of bulky devices is difficult. Claim 1. Multifunctional logic probe comprising a diagnostics unit for diagnosing a static circuit and dynamic dynamic state of a logic circuit, including a pulse estimator and indicator loop, which is connected to a pulse counter, in order to miniaturize and expand the functional capabilities, the gating node is entered into the dynamic state diagnostic unit of the logical circuit, and the static logical circuit diagnostic unit is implemented as a controlled generator a pulse torch and a light indicator, the controlled pulse generator consists of four serially connected logical inverters, between the outputs of the first and second of which a capacitor is connected, and between the common bus and the output of the third inverter there is a voltage divider The midpoint of which is connected to the input of the first inverter and is connected to the first input of the probe through the decoupling rejector, and the indicator light consists of two different LEDs th color, one of which Ii3 tokoogranichi vayuschy through the first resistor connected to the output of the third inverter is controlled emogogeneratora pulses, and the other through a second current limiting resistor connected to the output of the fourth inverter and the first output of the probe. 2. Probe on. p. 1, that is, with the fact that the gate node contains four elements 2I-NOT, 93 1 two inverters. two control triggers and a reset element, which is a microswitch, the second probe input connected to the input of the first element 2I-NOT, the output of which is connected to the counting input of the counter, the installation input of which is connected to the installation input of the first control 2I NOT, the first input of which is connected to the direct output of the second control trigger, the second input is connected to the output of the third element 2I-NOT, and the installation input of the second trigger is connected to the third input of the probe, the element m reset and the first input of the third element 2I-NOT, and the counting input of the second control trigger is connected to the output of the first, the inverter and the control inputs of the first and fourth elements 2I-NOT, the input of the fourth element 2I-NOT connected to the fourth input of the probe, and the output - to the counting input of the first control trigger, the output of which through the first inverter is connected to the second input of the third element 2I-NOT and the second inverter is connected between the output of the higher discharge of the counter and the second output of the probe. Sources of information taken into account in the examination 1. US Patent H, cl. .5, 1973. 2, USSR Copyright Certificate ff 651276, cl. G 01 R 31/28, 1976 (prototype). s r "