JPS60116046A - Logical circuit device - Google Patents

Abstract

PURPOSE:To prevent change of state of flip-flop etc. in a logical device provided with a shift register that scans in and holds data for diagnosis by providing a latch circuit in output side of the shift register. CONSTITUTION:At the time of ordinary operation mode, a selector circuit 1 receives the first select signal and selects input data of (n) bits inputted from an input terminal Din. At the time of diagnosing mode, it receives the second select signal and selects data for diagnosis scanned in from a diagnosing data input terminal TDin to the shift register and latched by a latch circuit 4 and gives to the body 2 of the logical circuit device. When scanning input data for diagnosis, taking in of the data to the body of the logical circuit device is checked, and change of state of flip-flop etc. can be prevented.

Description

[Detailed description of the invention] [Technical portion of the invention! l'j) The present invention is equipped with a shift register that scans in and holds patient data for the first diagnosis, and replaces this scanned-in data with the data input from the input terminal to the logic circuit device main body. This paper relates to the improvement of a logic circuit 12' that makes it possible to perform such diagnosis.

[Technical backbone of the invention and 5J1j 1 point] Recently, with the development of integrated circuit technology, circuit devices that combine a large number of logic circuits of 1 and 11 have been developed. These iy'6 logic circuit device IDs (dog 4 which is a combination of
;(The l-simulated logic circuit system is shown in I.pi a.

By the way, if we individually diagnose each logic function in the 0 logic circuit 4'j li', then t,j, 11'j
'+' is the key. Therefore, in the past, j, for example, j:
1lii i' (! A shift register is provided in the data input section of the circuit device (1-n), and the diagnostic human power γ-y is scanned into this/futrenostar and held, and the selector is turned on.) The input data for diagnosis is sent to the main body of the 111 logic circuit device in place of the data input via the data controller.

According to such a logic circuit device equipped with all shift registers, it is possible to diagnose the logic circuit device main body as if input data for diagnosis is given to the data input device. . Therefore, it is possible to take out only the logic circuit equipment to be diagnosed from the system, connect it to the diagnostic device V (for example, an emulator), and diagnose it while ignoring the data applied to the data input terminal. It comes off.

However, when the diagnostic input data is scanned into the shift register, the following problem may occur. That is, it operates by receiving data stored in the B logic circuit device (the main body is a data input terminal) and input data for diagnosis that has been scanned in repeatedly. If a change occurs in the state of the bean i 31j due to the data on the data scan date i, the original logical function will no longer be achieved. For this reason, there is a general rule that states that the states of all flip-flops in the AiJ logic circuit device must not be changed when scanning in the diagnostic input data. There is.

However, the main body of the logic circuit h'Pr is connected to the ii':i6 child (in the free ruff 0 float that is formed, there is a clear terminal asynchronous to the input line of the data).
There are often things that exist. Flip 7 like this
A diagnostic input beater scanned into the shift register by a logic circuit device '15'' with a 0-tube includes a device that activates the asynchronous terminal of the flip 7° flop. 1, a problem occurs when the state of the scan-in Itlkc R/' flip-flop changes 71. As a result, it becomes impossible to disconnect it.

Therefore, in the past, for the logic film of the main body of the logic circuit device, it is necessary to operate all the flip-flops synchronously.
Although we have established a
There was the problem of lodging that hindered freedom.

[Purpose of the invention]

The present invention has been made by omitting such q1 and 1, and its purpose is to apply a shift register to a logic circuit device 1 including an asynchronous flip-flop. The object of the present invention is to provide a highly practical logic circuit Wj configured to scan in diagnostic input data and perform a diagnosis.

[Summary of the invention]

The present invention includes a shift register that scans in diagnostic input data and holds it, and a shift register that scans in the input data for each time to this shift register and replaces it with data that is input from a child. It's equipped with a selector that powers the logic circuit board! l"11 equipment t-
', between the shift register and the selector,
The present invention is characterized in that a latte circuit is provided which latches the data scanned into the shift register and outputs it to the front h stain selector before the input data for diagnosis 1 is scanned into the shift register. It is something.

〔Effect of the invention〕

Thus, according to Akira Kimoto, when scan-in diagnostic input data, the latch circuit stops the data from entering the main body of the logic circuit device by 1) 14, and the above-mentioned data starts from the llij point where the scan-in ends. The circuit operates to take in diagnostic input data into the main body of the logic circuit device. Therefore, when the asynchronous thread of the logic circuit device 1 and the diagnostic input data scan-in IIJ,
The involuntary activation becomes powerful, and it is possible to make a thorough diagnosis.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

Figure 1 shows the four parts of the embodiment device If (: approximately If!f), Din is an n-bit parallel data input; This is a data input terminal.The n-bit data input in parallel through the n-tree data input terminal Dink is sent to the logic circuit device via each selector 1112 to 1n of the selector circuit 1. ζ′ is taken into the main body 2. This logic circuit device t;:
Diagnostic data for the main body 2 is obtained from the input ☆;1, ;child D in Elf? The data that is input serially is input serially one bit at a time from the previous R self-diagnosis data input terminal TDin, and is input into an n-stage shift register, ? It is now scanned in. This shift register 3 operates by firing the /ft clock to scan in the diagnostic data and hold it.

However, each shift stage of the shift register 3 is provided with a latch circuit 4 (41r42-4n) corresponding to the shift stage. This latch circuit 4 receives a latch signal at the end of scan-in of the diagnostic data, latches the data held in the shift register 3 in an orderly manner, and transfers the data to the selectors 'I + 72 to 1n, respectively. This is what is output.

Selector circuit 1 (selector '1+72 to 1n) is in normal operation mode! In response to the select signals of 1 and 1, n bits and 5 human input data inputted from the input terminal Din are selected, and this is applied to the main body 2 of the logic circuit device 19, and in the diagnosis mode, the second selenium) ( Upon receiving the number W, diagnostic data scanned into the shift register 3 and latched into the latch circuit 4 is selected and given to the logic circuit device main body 2.

The logic circuit device 2 to which input data or diagnostic data is selectively applied via the selector circuit (selector circuit) has a divine configuration depending on its logic circuit specifications. For example, there is a flip-flop 2 a +2b shown in FIG. 1 as an asynchronous circuit element constituting the one-way device 2 for JJI river i. The flip-flop 2a is asynchronously reset by receiving an active signal at its clear terminal, and the flip-flop 2b is asynchronously set by data via a logic circuit consisting of an inverter 2C OR circuit 2d. It is something. And these flip-flops 2
No. 46, which asynchronously activates the reset terminals and set terminals of h and 2b, can be directly inputted as the output of the selector circuit 1 (without going through a synchronous circuit).

Incidentally, the latte circuits 41+42 to 4n can generally be constituted by two AND circuits 5a and 5b, an OR circuit 5c, and an inverter circuit 5d, as shown in FIG. integrally with 3
It is also possible to implement the operation using two AND circuits 6h, 6b, 6c and an OR circuit 6d. Also, Figure 4 shows the 3rd
FIG. 2 is a signal waveform diagram showing the operating state of the circuit shown in the figure;
l1lA indicates the time of scan-in and the time of Bake diagnosis.

According to the present device configured in this manner, by applying the first select signal and causing the selectors 1Hr12 to 7n to select the data provided from the data input terminal Din, The power of the r-type can be seen in the one-inch logic circuit device main body 2. This causes the device 6 to perform its normal, original operation.

Then the device diagnosis begins 11. l, turns on the second select signal instead of the first select signal 46.

In this state, a shift clock is applied to the shift register 3, and in synchronization with this, the diagnostic data input terminal TDj
Diagnostic data is stored in n, and the diagnostic data is scanned into the shift register 3. At this time, shift
Since the diagnostic data scanned into the Nostar 3 is suppressed by the latch circuit 4, it is not given to the 1/C convex ii selector 1. It is worthless to be given. Therefore, when scanning in diagnostic data, the above-mentioned asynchronous flip-flop? A, 2h inn is not reset or set to Chigi χ1.

Thereafter, when the scan of data for one cut into the shift register 3 is completed, a latch signal is applied to the check circuit 4. As a result, the diagnostic data that has been scanned into the shift register 3 is transferred to the latch circuit 4, and then sent from the latch circuit 4 to the logic circuit device main body via the selector 1. It will be given to you.

Then, according to this diagnostic data, the logic circuit device main body 2
will be activated and its diagnosis will be performed.

Therefore, the wooden f6 that is constructed and operates as described above does not have any negative effect on the logic circuit device main body 2 when scanning data for diagnosis, so that the diagnosis can be performed reliably. becomes possible. Moreover, upper h
There is a problem with iL scan-in, so there is no fiu
The degree of freedom in pulling the crotch of the main body 2 of the logic circuit equipment increases, and in its role, the constraint condition of synchronizing all the threads using a clock is brought into play. 1. The equipment configuration and its control are f? 11, and has great practical advantages.

It should be noted that the present invention is not limited to the above embodiments.

For example, if it is diagnostic data that is scanned/scanned into the d-shiftre/Zostar 3, the inside of the buried circuit system Io body 2 can also be scanned/2.
The present invention can be applied in the same way to a device configured to scan data, or a device configured to scan out the scanned-in diagnostic data to a data output section, and the same effects can be obtained. be given Should I scan in again? [The number of data bits, its scan-in speed, etc. can be determined according to the device specifications. In short, the present invention can be implemented with various modifications within a range that deviates from its spirit.

[Brief explanation of drawings]

FIG. 1 shows the manufacturing section M of an example of the production apparatus of the present invention. 'C, about 4
'! Figure 2 shows the latch circuit σ in the same embodiment.
) Diagram showing an example of the configuration, Figure 3 shows an example in which a latch circuit and a selector are integrally configured.
FIG. 3 is a diagram showing operating waveforms of the circuit shown in the figure. l...Selector, 2...Logic circuit device'' body, 3
...Shift register, 4...Latch circuit.

Claims (1)

[Claims] 1. A shift register that scans in diagnostic input data and holds it;
=i+a selector that selectively takes in diagnostic manual data or data given through an input terminal, and a predetermined operation according to the data taken in via this selector'ff:
11 In the circuit device, between the shift register and the selector, the diagnostic cover for the shift register is located between the shift register and the selector. Logic circuit device 6