JPH02799B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for testing a magnetic bubble memory device, and more particularly to a method for testing the functionality of a magnetic bubble memory device that reduces test time.

Generally, as a transfer circuit for transferring magnetic bubbles, a soft ferromagnetic thin film pattern such as permalloy is formed on the magnetic bubble magnetic thin film, and this pattern is magnetized by a rotating magnetic field that rotates within the plane of the pattern. A well-known method is used. In this field access method, a known circuit configuration method called Meijer minor loop method is used to shorten the information access time.

FIG. 1 is a block diagram showing an example of a memory chip using the Meijer minor loop method, and is also an example of a memory chip to which the testing method of the present invention is applied. In the figure, 1 is a magia loop, and this magia loop 1 is, for example, 1a, 1
This is a closed loop in which a plurality of bits consisting of a plurality of chevrons b, 1c, . 2 is a minor loop, and this minor loop 2 forms a closed loop with a bubble domain transfer track of a plurality of bits, and is composed of, for example, a large number of continuous loops of T and I patterns arranged in parallel. One end of each of the minor loops 2 is connected to the major loop 1 via a transfer gate (T) 3 bit by bit, and a transfer command (a local magnetic field generated by a pulse current is used to switch the track of the bubble domain). Input/output data blocks are exchanged between the major loop 1 and the minor loop 2 by means of the major loop 1 and the minor loop 2. Here, the circles on the major loop 1 and the minor loop 2 represent the bit positions of the shift register, and the arrows represent the shift direction. Also, at one end of this mager loop 1, information “1”,
Generates magnetic bubbles by sending write signal G and erasure signal A in response to data blocks such as “0”.
A bubble generator/extinguisher for extinguishing a bubble, a magnetic bubble detector 5 for detecting the presence of a bubble domain and taking it out as a detection signal (S), and a bubble generator for transmitting the bubble domain in the magister loop 1 to the magnetic bubble detector 5. A replicator 6 that sends out a replicate signal (R) for dividing the signal is connected to each.

In the magnetic bubble memory device configured in this way, information is written by first sending a write signal G and an extinction signal A to the magnetic bubble generator/extinguisher 4.
The conductor u is operated to cause new information to be written on the mager loop 1 bit by bit by the conductor u. Then, the written information is transferred onto the mager loop 1 and is transferred from the mager loop 1 to the minor loop 2 by the gate operation (called transfer in) of the transfer gate (T) 3, and this information is marked with a black circle. As shown, it will be stored in each bit of minor loop 2. Next, when reading out the information stored in the minor loop 2, for example, the information indicated by the black circle is first transferred in the direction of the arrow in the minor loop 2, and then the gate operation (transfer gate) of the transfer gate (T) 3 is performed. (referred to as ``out''), it is transferred to the magia loop 1. The information transferred to the mager loop 1 is transferred onto the loop and sent to the detector 5 by the replicator signal (R) of the replicator 6, and when it passes through the detector 5, it is read out to the outside. Then, the information of this major loop 1 is again stored in the original position of the minor loop 2 via the transfer gate (T) 3. Then, when the information signal written in the minor loop 2 is no longer needed and a new information signal is to be written, the erasure signal A is added to the bit corresponding to the old information signal immediately before writing the new information signal G. was supplied to erase the old information signal, and then new information was written. In other words, this state is
To explain using the current timing diagram shown in the figure, when writing new information "1", "1", "0", the bubble generator of the magnetic bubble generator/extinguisher 4 will write bit by bit. Pulse current of information signal G corresponding to information “1” and “1” for numbers 1a and 1c
ig is supplied, and for information "0", bit number 1e is in a state where pulse current ig is not supplied and information is written. At this time, bit number 1 is output from the magnetic bubble generator/extinguisher 4.
A pulse current ia for erasing old information is sent to a, 1c, and 1e immediately before the pulse current ig of the information signal G is supplied, and the old information is erased immediately before new information is written. .

The magnetic bubble memory device constructed in this way is subjected to functional and operational tests in the final process. When using a bubble memory, the most severe operating conditions, that is, the mode with the strictest operating margin, are when the use of the bubble memory is started and when it is stopped, in other words, when magnetic bubble transfer is started and stopped. Therefore, the operation test is performed while repeating start and stop operations for transferring magnetic bubbles within the memory chip.

The conventional functional test method writes test data to a specific bit (specific page) of each minor loop 2, then stops the transfer of bubbles at a predetermined timing, starts transferring bubbles after a certain period of time, and then The method was to read the data of the specific page from the minor loop and check whether it is correct or incorrect, and repeat the series of operations over the entire page range. This test method had the disadvantage that the test time was long because the operations of writing, stop/start of bubble transfer, reading, and confirmation of correctness were repeated.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for testing the functionality of magnetic bubble memory devices, which improves the above-mentioned conventional drawbacks. According to the present invention, test data is first written over all pages (in all bits of the minor loop). Specifically, one page of data is serially transferred from the bubble generator 4 to the mager loop 1, and at a predetermined timing, the transfer gate 3 transfers the data of the one page of the mager loop to the first page of each minor loop 2. The test data is transferred in parallel to the bit positions (addresses) of , and this operation is repeated to write test data over all pages. Thereafter, a method is provided in which the transfer of bubbles is continuously stopped and started for each bit, and then the stored data is read and tested. Note that the reading of stored data is the reverse of the above-mentioned writing, and the data at the address of the first page of minor loop 2 is transferred in parallel to mager loop 1 at a predetermined timing, and
One page of data is serially read out by the detector 5, and by repeating this operation, reading out the test data over all pages is completed. Verification of write data and read data is performed by the host computer. According to this method, it is possible to shorten test time and test pattern dependence. Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 3 is a block diagram of the main parts of a magnetic bubble memory chip for explaining an example of the test method for magnetic bubble memory elements according to the present invention. Since the same symbols as in the previous figure are the same elements, the explanation thereof will be omitted. . In the same figure, this method does not exchange data between the minor loop and the major loop during the repeating start/stop period, and stops the magnetic bubble B every time it is transferred during the start/stop operation, keeping the data constant. Repeat the action of starting after the specified time.

According to such a test method, for example, if the number of bits in one minor loop 2 is 535 bits, the time to transfer one bit of magnetic bubble B is 10 μsec, and the stop time at start/stop is 10 μsec, then in the conventional method, all addresses are -Write, all address and read tests require approximately 11.5 seconds, but with the present invention, the test time is approximately 2.9 seconds, reducing the test time to approximately 1/4.

As explained above, according to the testing method for magnetic bubble memory devices according to the present invention, extremely excellent effects such as being able to significantly shorten the testing time can be obtained since start and stop operations are performed continuously.

[Brief explanation of drawings]

FIGS. 1 and 2 are diagrams for explaining an example of a magnetic bubble memory element, and FIG. 3 is a diagram for explaining a testing method for a magnetic bubble memory element according to the present invention. 1... Meijer loop, 1a, 1b, 1c~1
n...Bit, 2...Minor loop, 3...Transfer gate, 4...Magnetic bubble generation, extinguisher, 5...Detector, 6...Replicator, 7...
Annihilator.

Claims (1)

[Claims] 1. A test method for a magnetic bubble memory element comprising at least a plurality of minor loops for storing and holding magnetic bubbles as a storage medium in response to an information signal, which includes the steps of writing test data into all bits of each minor loop, and writing test data into all bits of each minor loop. A magnetic bubble characterized by comprising a step of repeatedly stopping and starting the transfer of the magnetic bubble every time one bit of the test data is transferred, and a step of reading the stored information from the minor loop and testing it. A test method for memory devices.