JPH0225110A - Counter circuit - Google Patents

Abstract

PURPOSE:To diagnose the count operation of all bits in a short time by providing one or plural selection means selecting a diagnostic countup signal inputted externally and outputting the result as a carry signal or a borrow signal to the most significant part of the counter. CONSTITUTION:A counter low-order part 1 and a high-order part 2 are operated separately and in parallel at the diagnostic operation. Thus, in the case of count operation diagnosis of all bits, it is not required to await counting till all bits being the sum of the low-order part 1 and the high-order part 2 overflow. The count is implemented till either the low-order part 1 or the high-order part 2 overflows. In this case, the circuit is normal when overflow signals 301, 401 of the low-order part 1 and the high-order part 2 are outputted and if not, the circuit is possibly faulty. Thus, the diagnosis of the count of all bits is implemented in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a counter circuit, and particularly to a counter circuit that requires diagnosis.

Traditionally, a method for diagnosing a counter circuit with a long bit length is to send a count-up or count-down signal to the counter circuit a fixed number of times, and check whether the counter value correctly increases or decreases by the number of times the signal is applied. There was a way to check.

Also, set the value just before overflow or underflow in the counter circuit in advance, and after sending the count-up signal or count-down signal several times, check whether an overflow (carry) signal or underflow (borrow) signal is output. There was also a way to do that.

However, in the conventional method of diagnosing a counter circuit with a long bit length as described above, there are count values that are not counted midway through, and it does not check whether the counting operation of all bits is performed correctly. There was a drawback. Furthermore, if all count values are counted to check the counting operation of all bits, the longer the bit length of the counter circuit, the longer the time required for diagnosis, which is not suitable as a diagnostic method.

1 Throne 1 Deposit An object of the present invention is to provide a counter circuit that can shorten the time required for diagnosis.

The counter circuit of the present invention has N digits (N is an integer of 2 or more).
is divided into M parts (M is a positive integer and M≦N),
an N-digit counting means in which each of the M parts changes a count value in response to input of a predetermined signal; and an input for simultaneously inputting the predetermined signal to each of the M parts in response to an external command. It is characterized by having a means.

K-sama Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of a counter circuit according to the present invention. In FIG. One counter is composed of a lower counter part 1 and an upper part 2.

In this embodiment, a count-up type counter circuit will be explained.

(1) During normal operation In cases other than normal operation, that is, diagnostic operation, select signal 2
01 becomes the normal operation mode, and the selection circuit 3 selects the overflow signal 301 of the lower counter section 1 and outputs it as a signal 302 to the upper counter section 2. At this time, when a count-up signal 101 is input from the outside, the counter lower part 1 starts counting operation.

When the lower counter section 1 overflows, it outputs an overflow signal 301. This overflow signal 301 is inputted to the counter upper section 2 as a signal 302 via the selection circuit 3. As a result, the upper part of the counter 2
counting operation is performed.

In this way, during normal operation, the counter lower part 1 and upper part 2 work together as one counter.

(2) During diagnostic operation In the case of diagnostic operation, the selection signal 201 becomes the diagnostic operation mode, and the selection circuit 3 selects the diagnostic count-up signal 102 and outputs it to the counter upper section 2 as a signal 302. At this time, the counter lower part 1 and upper part 2
are independent counters.

Therefore, when the count up signal 101 is set, counting of the lower part 1 of the counter starts, but even if the lower part 1 of the counter overflows, the overflow signal 30
1 does not pass the selection time FNI3, so the upper part of the counter 2
Also, the diagnostic count-up signal 10
When 2 is input, the signal 302 is input via the selection circuit 3, so the counter upper part 2 starts counting regardless of the operation of the lower part 1.

In this way, during diagnostic operation, the counter lower section 1 and upper counter section 2 can operate separately and in parallel (simultaneously). Therefore, when diagnosing the counting operation of all bits, it is not necessary to count until all bits in the lower part 1 and upper part 2 of the counter overflow, but only the number of times that the lower part 1 and the upper part 2 of the counter overflow, respectively. All you have to do is count, and at this time the counter lower part 1
If the overflow signals 301 and 401 from the host unit 2 and the host unit 2 are output, it is normal, and if not, it is known that there is a possibility of a failure.

In other words, diagnosis using this method can dramatically shorten the diagnosis time. It is clear that diagnosis can be made in a shorter time if a plurality of selection circuits are provided and the counter is divided into smaller pieces accordingly.

Further, in this embodiment, a count-up type counter circuit has been described, but it is clear that a count-down type counter circuit also has the same effect.

As explained above, the present invention selects either the overflow signal or underflow signal of the lower part of the counter and the diagnostic countdown signal or diagnostic countdown signal inputted from the outside. 1 selection means for outputting as a carry signal or borrow signal to the upper part
By providing one or more, there is an effect that even in a counter circuit with a long bit length, the counting operation of all bits can be diagnosed in a very short time.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a counter circuit according to an embodiment of the present invention. Explanation of symbols of main parts 1... Counter lower part 2... Counter upper part 3... Selection circuit

Claims (1)

[Claims] (1) N digits (N is an integer of 2 or more) are divided into M parts (M is a positive integer and M≦N), and each of the M parts has a count value according to the input of a predetermined signal. 1. A counter circuit comprising: N-digit counting means for changing the value; and input means for simultaneously inputting the predetermined signal to each of the M parts in response to an external command.