JPS63205899A - Semiconductor memory driving device - Google Patents

Abstract

PURPOSE:To attain the data processing with reliability by detecting and storing a defect address of a memory so as to avoid the defect address thereby using only normal addresses effectively. CONSTITUTION:A defect address representing a defective location of a memory 20 is calculated by a microprocessor of an arithmetic unit 24 provided with a ROM 26 to apply de-interleaving and error correction in the inside is calculated. The defect address is stored in a defect address storage section 28, and an address generating section 30 references the storage section 28 to inhibit the designation of the defect address. Thus, the defect address is avoided only the normal address is used effectively to attain the data processing with reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor memory drive device that avoids the use of defective addresses in a readable/writable memory element (RAM).

[Conventional technology]

Conventionally, a disc playback device that reads out music information etc. stored on a compact disc (CD) etc. stores encoded data representing the music information etc. read out from the CD in a storage element, decodes the encoded data, and decodes the encoded data. After de-interleaving and error correction, the music data is reproduced and played back as audio.

In this disc reproducing apparatus, for example, as shown in FIG. 3, a CD 2 is rotated by a motor 4, and the linear velocity of the recording track of the CD 2 is controlled to be constant.

The pink-up 6 irradiates a laser beam 8 as a detection medium focused on the track of the rotating CD 2, receives the reflected light, and converts it into an electric signal to obtain a detection signal. This detection signal is applied to a preamplifier 10, extracted as an RF signal, and then applied to a digital signal processing unit 12 as a demodulation means for demodulating the EFM, and also to a phase locked loop (PLL) 14. Added. The PLL 14 extracts a frame synchronization signal from the RF flaw signal and applies the frame synchronization signal to the digital signal processing section 12, and the digital signal processing section 12 extracts the frame synchronization signal from the RF flaw signal.
Demodulates the EFM signal from the RF flaw signal. The EFM signal is stored in a memory element (RAM) 16 that stores de-interleaved data, error correction data, etc., and is decoded as music data etc. by an arithmetic unit 18 that calculates a cross-interleaved Reed-Solomon code (CIRC). At the same time, after correcting errors in the reproduced data, the reproduced music data is reproduced. De-interleaving reproduces the original data by rearranging the order of continuous data (interleaving) according to a certain rule in order to prevent missing music data. Also, error correction This process compensates for data errors caused by scratches, dust, etc.

After such processing, the obtained music data DO is added to an audio system such as filter processing, DA conversion, and amplification, and is reproduced as audio.

Arithmetic unit 18 in such a disc playback device
is a ROM or central processing unit (CP) that stores processing programs that perform de-interleaving, error correction, etc.
U), and together with the RAM 16, it is configured as a single chip IC.

[Problem that the invention seeks to solve]

By the way, in such a 1-chip IC in which a memory element such as RAM 16 is installed inside to write or read necessary data, a test is performed to determine whether the RAM 16 is good or bad when the IC is shipped or mounted on a device. It is necessary to check.

However, memory testing of a single-chip IC with a large amount of RAM installed inside is troublesome and takes a considerable amount of time. Even if the IC has a memory part that does not cause any problems, the IC will be treated as defective, causing an increase in manufacturing costs.

In disc playback devices, etc., even when operating normally, a defective location may occur in the RAM 16, but in such cases, conventional operations use the defective location, so normal data writing operations and There is a possibility that a reading operation cannot be obtained, causing a malfunction, or that music information cannot be reproduced normally.

Therefore, the present invention provides a function to determine whether the RAM is good or bad, thereby making it possible to avoid the use of defective addresses.

[Means for solving problems]

As shown in FIG. 1, the semiconductor memory drive device of the present invention includes a defect detection means (arithmetic unit 24) that detects a defective address in a writable and readable memory 20, and a memory device that stores the detected defective address and stores the detected defective address. The storage means (defective address storage section 28) that avoids the specification of .

[For production]

A defective address in the memory 20 is detected and the defective address is stored in a storage means. Then, write the necessary data, and
At the time of reading, the designation of the defective address is avoided so that the defective address is not used.

〔Example〕

FIG. 1 shows an embodiment of a semiconductor memory driving device of the present invention.

The memory (RAM) 20 is installed as an internal memory inside one chip of IC, or installed as an external memory connected to the outside of the IC, together with a semiconductor memory drive device. This memory 20- corresponds to the RAM 16 in the disc playback device shown in FIG. This memory 20 is composed of, for example, a writable and readable storage element, and stores information read from a storage means such as a CD and other input information.

This memory 20 is linked via a data bus 22 to an arithmetic unit 24 serving as defect detection means. This arithmetic unit 24 is composed of a microprocessor equipped with a storage section (ROM) 26 for performing de-interleaving and error correction, and receives timing signals φm1 to φm.
, it is possible to perform CIRC Galois field calculations in synchronization with , and, for example, performs 2n error code correction when playing a CD.

That is, the memory IJ20 is
The address representing the defective location (defective address) is calculated, and the address is recorded in the defective address storage section 28 as a storage means.

This defective address storage section 28 can be configured, for example, by a register within the CPU.

The address generation section 30 is a means for specifying an address in the memory 20, but it prohibits the specification of the defective address recorded in the defective address storage section 28, thereby avoiding the use of the defective location during actual operation.

Next, FIG. 2 shows a processing program for detecting a defective address and avoiding the use of the defective address.

In step S1, the defective pattern program is read from the ROM 26 and written into the RAM of the CPU.

In step S2, the arithmetic unit 24 is operated on the memory 20, and in step S3, a defective address in the memory 20 is detected.

Next, in step S4, the defective address of the memory 20 is stored in the defective address storage section 28.

In step S5, when the recorded defective address arrives in the calculation of the calculation unit 24, weighting is applied to change the calculation.

Then, the process moves to step S6 and normal operations are performed.

This program operation avoids the use of defective addresses and effectively uses only normal addresses, making it possible to perform reliable data processing.

In the embodiment, a case is explained in which the memory 20 is installed in a single-chip IC, but even if it is installed as an external memory, a similar program can be used to detect a defective address and avoid its use. be able to.

〔Effect of the invention〕

According to this invention, a large scale memory element can be integrated into a single chip IC.
If the memory element is held on top, there is no need to perform a memory test, which saves the time and effort required for the test, and reduces the cost of the memory element as well. can be used equally as a good product, and I
The manufacturing cost of C can be reduced. Further, even if a part of the memory element breaks during use of the IC, it is possible to ensure that only the normal part is used, thereby avoiding malfunction.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the semiconductor memory drive device of the present invention, FIG. 2 is a flowchart showing an operation program of the semiconductor memory drive device shown in FIG. 1, and FIG. 3 is a block diagram showing a disc playback device. It is. 20...Memory 24...Arithmetic unit (failure detection means) 28...Failure address storage section (storage means) Fig. 1

Claims (1)

[Scope of Claims] A semiconductor memory drive device comprising: defect detection means for detecting a defective address in a writable/readable memory; and storage means for storing the detected defective address to avoid designation of the address.