JPS6051188B2 - Driving method of magnetic bubble memory - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a driving method for shortening the access time of a serial loop type magnetic bubble memory.

A magnetic bubble memory is extremely useful as a rewritable large-capacity nonvolatile memory, and this memory is used, for example, as shown in FIG. In the figure, MEM is a magnetic bubble memory, and the central processing unit (microprocessor) MPU
and a bus B, and a small capacity random access memory RAM is connected to this bus. There are two types of magnetic bubble memory MEM: major and minor loop types and serial loop types.The serial loop type uses a transfer path SR consisting of a permalloy pattern that meanderes but forms one loop, as shown in Figure 2. This device transfers and holds magnetic bubbles, and the signal is in serial format. R
This is why AM is used, and MPU is 4 bits,
Since multiple bits such as 8 bits are transferred in parallel, serial-to-parallel conversion is performed with the serial bubble memory. Although this serial bubble memory has a simple structure, it has the disadvantage of long access time. In addition, in Fig. 2, R
EP is a replicator, DET, ~DET, is a detector, ANH is an anilator, GEN is a generator, Lx
is an X coil for generating a driving magnetic field, and Ly is a Y coil. This magnetic bubble memory MEM is 72 and 740 for details.
This is a 32-bit example, and the location of the generator GEN is (
O) Bits corresponding to each position are set as (7 bits)
3904), (73907), etc. Since the total number of bits is 74032, the (0)th bit and the (74032nd)th bit are the same bit, and bubble generation, detection, and erasure are performed at this position. In this bubble memory, all bits are divided into 144 bytes, each of which is one page, and each page is provided with several bytes of start and end control data and a 128 byte data area.

When writing new data Dn' to the n-th page of such a magnetic bubble memory MEM, as shown in FIG. 2 After writing additional data Dn' to the RAM, 3 magnetic bubble memory rv1EM
When the nth page comes back after the bubble has gone around
It is common practice to write all the data of M to the n pages. The data to be written is Dn″+1, Dn″+2
・・・In cases where it says, each page n+1, n+2...
Since the same thing is done for . . . , the time required for data writing becomes considerably long. Current magnetic bubble memories are generally used because they do not require a slow speed as long as they can handle a large amount of data, but it goes without saying that a short access time is desirable. Particularly in applications where data is frequently written and read in small capacity units of several tens of bytes or less, the access time is practically negligible. The present invention aims to improve this point, and provides a method for driving a magnetic bubble memory having a central processing unit having a serial loop and a random access memory. When writing data, first read the data already stored in the n-th page to the random access memory, then write the data to the random access memory, and then write all data in the random access memory. The (n+)th magnetic bubble memory
1) This is characterized by writing on the page, and this will be explained in detail below with reference to the illustrated embodiment.

FIG. 4 shows an embodiment of the present invention, and the same parts as those described above are given the same reference numerals.

In the present invention, when the transfer capacity at one time is less than one page (128/item), data is always transferred one page at a time. In order to improve the access time, when writing data Dn'', Dn''+2, . The data Dn already stored on the nth page is read to the RAM, and new additional data Dn'' is written to the RAM.Then, all the data in the 3RAM (
Dn+Dn'') on the next (n+1) page. Similarly, when writing the next data Dn''+2, write the 4th page (
Read data Dn+2 of page n+2) to the RAM, and write new data D″n+2 to the RAM. Then, 6R
All AM data 7 (Dn+2+D″n+2) is converted to the next (
Write on page n+3). At this time, n+1, n+3,...
・If the data on the page is not needed, it can be transferred from RAM (D
n+D″n), (Dn+2+D″n+2) is erased before writing to the page. Also, if the data is necessary, the RAM data is N
．． +1, n+3, . . . pages, write data following the data on that page. This process can be easily done using termination control data. If necessary, the correspondence between these data and the page in which they are written can be managed by the user, or an identification code can be attached to each data, and when reading it, all bytes of the bubble memory can be scanned. Search for the required data. In this method of the present invention, writing 4, 6, etc. from RAM to bubble memory is performed as data Dn, D
n+2,... is executed for the next page n+1, n+3,... after the read page N, n+2,..., so there is no need to wait for one cycle of the loop. The access time is much shorter than the drive method.

For example, if the transfer rate is 100 Kbit/s, 1
The access time for a page is as shown in Figure 3 (32K
The average access time per byte is 370rT1SeC), which enables about 30 times faster access.

Therefore, even a serial loop type magnetic bubble memory can sufficiently store data continuously output from the keyboard in a nonvolatile memory.

[Brief explanation of drawings]

4 (Figure 1 is a block diagram showing an example of a system using a magnetic bubble memory, Figure 2 is a block diagram showing an example of a serial loop type magnetic bubble memory, and Figure 3 is a block diagram showing an example of a system using a magnetic bubble memory). Explanatory diagram, FIG. 4 is an explanatory diagram showing one embodiment of the present invention.

Claims (1)

[Claims] 1. In a method for driving a magnetic bubble memory having a serial loop, a central processing unit, and a random access memory, when writing data to the n-th page of the magnetic bubble memory, the n-th page After reading data already stored in the random access memory into the random access memory and writing the data into the random access memory, all data in the random access memory is transferred to the (n+1)th page of the magnetic bubble memory. A method for driving a serial loop type magnetic bubble memory characterized by writing.