SU1383237A1 - Logical probe - Google Patents

Abstract

The invention is intended for commissioning, monitoring and diagnostics of digital devices made on integrated circuits, and allows you to expand the functionality of the device. The logical probe contains an input repeater 1, a threshold unit 2, a pulse counter 7 and a display unit 8. The introduction of the switch 9 modes, the elements And 3 and 4, the formers 5 and 6 pulses and the formation of new functional connections increases the number of monitored parameters. 1 sludge;

Description

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The invention relates to electrical measuring equipment and is intended for setting up, monitoring and diagnosing digital devices made on integrated circuits.

The purpose of the invention is to expand the functionality of the probe by increasing the number of monitored parameters.

The drawing shows a structural diagram of a logic probe.

The logical probe contains an input repeater 1, a threshold unit 2, two elements 3 and 4, two formers 5 and 6 pulses (on the falling front of the input signal), a counter 7 pulses (reversible), an indication block 8, a mode switch 9.

The first input of the first component IZ is connected to an external source of the strobe signal and the first input of the second element I 4, the second input of the element I 3 is connected to the first input of the display unit 8, the input of the first shaper 5 pulses, the source of the logical unit level and the first output of the mode switch 9, the second terminal of which is connected to the common bus, and the output of the first driver 5 is connected to the input of the installation of the counter 7 at zero, the overflow output of which is connected through the second driver 6 of the pulses to the subtracting input of the same 7, the information input input of which is connected to the output of the second element 4, the second input of which is connected to the output of the threshold block 2 and one information input of the first decimal place of the counter 7, the third information input connected to the corresponding outputs threshold unit 2. The input of the threshold unit 2 is connected to the output of the input repeater 1, and the information outputs of all bits of the counter 7 are connected to the corresponding inputs of the display unit 8.

The device works as follows.

If the mode switch 9 is in the open state, then at the same input of the element And 3 there will be a positive potential, and if there is a signal, the Strobe element And 3 will work and at the input S of the counter 7 there is a positive potential that will block the counting inputs and enable.

receiving information on information inputs. The information on the information inputs of the pulse counter 7 comes in the form of a combination of zeros and ones from the threshold block 2, which determines the presence of a logic zero level, a common bus (ground) and a power bus at the input of the probe . The incoming information is immediately entered into counter 7 and appears at the information outputs. The display unit 8 converts the information received from the outputs of the pulse counter 7 into codes for multi-element indicators, and displays it with appropriate symbols. Thus, in the first one, the discharge of the multi-element indicator 8 of the display unit displays information about the potential of the controlled point in which the probe (input) of the probe is installed. The remaining bits of the indicators and the counter in this mode are not used and are in the zero state. If the mode switch 9 is in the closed state, then at the input of the element And 3 there will be a zero potential and its operation will be prohibited. At the input S of the counter 7, a low (zero) potential will be constantly present and the recording of information on the information inputs of the counter will be blocked, and the forward or reverse counting of pulses will be allowed. In this case, you can count the number of pulses at a controlled point of a digital node or microcircuit over a period of time, determined by the duration of the signal Page 10 transmits pulses to the input + i of the counter 7 from the output of the threshold unit 2, which fixes the logic level at the probe input. In other words., All the pulses at the probe input, the upper level of which is equal to or exceeds the logical unity level, arrive at the summing counting input -1 of counter 7 and are counted by it over the entire period of time determined by the duration of the external enabling signal Strobe. If the counter 7 is completely filled and with the arrival of the next pulse is reset to zero, then at the output of the overflow P of the counter, according to Wits sh-pulse, after which, i.e. by its decay, shaper 6 generates a short pulse arriving at subtracting input -1 of counter 7. All triggers of counter 7 are returned from the zero state back to one. The process is repeated with the subsequent receipt of any number of input pulses. Thus, the probability of an error in counting the number of pulses, exceeding their capabilities, is eliminated.

The pulse shaper 5 generates a reset pulse to the counter zero with each pressing of the switch 9, i.e. with the appearance of a low level at its entrance. Consequently, the counting of pulses in each new measurement cycle starts from zero. If any

signal strobe prohibits the operation of the element and 4.

Claims (1)

Invention Formula Logical PROBE; containing an input repeater, a threshold unit, a pulse counter, a display unit, the output of the input repeater is connected to the input of the threshold unit, and the input is connected to a terminal for connecting a control object, characterized in that, to expand its functionality, a mode switch is inserted into the probe, two pulse shapers and two And elements, the first input of the first And elements connected to an external source the need to check the gate signal with the first one If a single pulse or a series of pulses corresponds to or does not correspond to logic levels, then a positive pulse is used as a strobe signal, combined in time and duration with the tested one. In this case, the switch 9 is in a non-quenched state, therefore, during the pulse action, the Strobe input S has a high potential, i.e. the first digit of the counter, on the information inputs D1, records information about the level of the monitored pulse. If, for example, the level of a monitored pulse during the period of the Strobe signal is above a logical zero, but below a logical one, then the outputs of the threshold block will be 1100. This code will come from the information inputs of counter 7 to its outputs, and then to the inputs of display 8 and will cause, for example, the glow of the symbol H in the first digit of the indicator, which characterizes the mismatch of the monitored impulse to a logical level of zero or one. After the end of the strobe pulse, the input S will have a low S level but no pulse counting, since the low level Editor M. Vasiliev Compiled by G. Narchenko Tehred M.Didk Order 1291/42 Circulation 772 VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab, 4/5 five 0 five 0 five the input of the second element And, the second input of which is connected to the first input of the display unit, the input of the first pulse shaper, a terminal for connecting the source of the logic unit level and the first output of the mode switch, the second terminal of which is connected to the common bus, and the output of the first pulse shaper is connected to the input setting the pulse counter in O, the overflow output of which is connected through the second pulse shaper to the subtracting counting input of the pulse counter, the resolution input of which is connected to the output in the second element is connected to the first output of the threshold unit and the first information input of the pulse counter; the second, third and fourth information inputs of which are connected to the corresponding second, third, fourth outputs of the threshold unit , the information outputs of the pulse counter are connected to the corresponding inputs of the display unit, and the pulse counter is reversible. Proofreader M-Demchik Subscription