JPH03224041A - Capacity recognizing method for externally connected ram - Google Patents

Abstract

PURPOSE:To reduce the chip area of an IC and to decrease the number of external parts by making a voice solid-state recording and reproducing IC recognize automatically the capacity of an externally connected RAM with an access given from the IC at the time of an initial action. CONSTITUTION:The data are read out of the address of a RAM 2a at the time of the initial action of a voice solid-state recording and reproducing IC 1. These read data are held by the IC 1 and a certain data is written into the address of the RAM 2a. Then the data is read again out of the address of the RAM 2a. If the coincidence is secured between the read data and the written ones, it is decided that the RAM 2a is connected to the IC 1 and is normally working. Then the areas are previously secured in 1st and 2nd addresses of respective RAMs to write the specific data indicating that the memory capacity is already checked. Simultaneously, an area is secured in a 3rd address to write the memory capacity data. When the memory capacity is recognized at the time of initial action, the specific data indicating that the memory capacity is already checked are written into the 1st and 2nd addresses of respective RAMs together with the memory capacity data written into the 3rd memory respectively. Thus the IC chip area is reduced and the number of external parts can be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for making an audio solid-state recording and reproducing IC recognize the capacity of an externally connected audio data storage RAM.

[Conventional technology]

Conventionally, audio solid-state recording and playback ICs had RAM for storing audio data.
When externally connecting an IC, a method has been adopted in which memory capacity information is set externally in advance in accordance with the memory capacity to be connected, in order to make the IC recognize the connected memory capacity.

[Problem to be solved by the invention]

Conventional audio solid-state recording and playback ICs have adopted a method of setting memory capacity information externally in order to recognize the capacity of externally connected audio data storage RAM.
There are problems in that the IC area increases due to the increase in the number of terminals for setting, and the number of external components increases.

The present invention was made to solve the above problems.
It is an object of the present invention to provide a method for making an IC recognize the capacity of an externally connected RAM without setting it from the outside.

[Means to solve the problem]

In the method of the present invention, during initial operation, the audio solid-state recording and playback IC
Second, the capacity of the externally connected RAM is automatically recognized by access from the IC.

〔Example〕

FIG. 1 shows an example of the connection state of the RAM to the solid-state audio recording and reproducing IC.

In the figure, 1 is an audio solid-state recording and playback IC, 2a.

2b and 2c are RAMs, 3 is an address bus, 4 is a data bus, and 5 is a chip select line.

The present invention will be explained in detail below.

During the initial operation of the audio solid-state recording and reproducing ICI, data is read from the address of the RAM 2a (the method for accessing the address is explained later), and the audio solid-state recording and reproducing ICI retains that data, and stores certain data (e.g. The following 4 patterns; OF', 5AHA5'FO')
is written to that address, and data is read from that address again. When the written data and the read data are compared and they match, it is simultaneously determined that the RAM 2a is connected and is operating normally. After that, the data held by the audio solid state recording and playback ICI is written to restore the original state.

The method of accessing the address is to count up the LSB (least significant bit) and shift-amplify bits 1 to MSB (most significant bit) each time there is an overflow.

By doing the same thing as above for the RAMs 2b and 2c, it is possible to know the connected memory capacity.

In order to shorten the processing time of the above method, the present invention provides an area for writing specific data indicating that the memory capacity has been checked at the first and second addresses of the RAM, and at the third address. Secure an area to write memory capacity data, and perform audio solid-state recording and playback during initial operation.
After the capacity recognition by access from CI is completed, each RAM
Specific data indicating that the memory capacity has been checked is written to the first and second addresses, and memory capacity data is written to the third address.

Then, it was decided that subsequent capacity recognition would be performed by reading only from the first, second, and third addresses.

FIG. 2 is a flow chart of capacity recognition using the above method, and FIG. 3 is a memory map showing a method of displaying addresses in FIG.

First, data is read from the first and second addresses of the externally connected RAM, and it is checked whether the read data matches specific data. If they match, the memory capacity data is read from the third address. Read the corresponding RAM
Recognize the capacity of

If the data do not match, the capacity of the RAM is recognized by writing the data at the address described above and reading data from that address, and the first, second, and third addresses are Predetermined data is written to each.

〔Effect of the invention〕

As explained above, according to the present invention, it is no longer necessary to externally set connection memory capacity data to the audio solid-state recording and playback IC in advance, and the chip area of the IC can be reduced by reducing the number of terminals for setting. This has the effect of reducing the number of external parts.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an example of the connection state of RAM to the audio solid-state recording and playback IC, FIG. 2 is a flowchart of the capacity recognition method of the present invention, and FIG. 3 is a memory map showing the address display method in FIG. It is. 1...Audio solid recording and playback IC12a, 2b, 2C
...RAM, 3...address bus, 4...data bus, 5...chip select line. Utility model registration applicant New Japan Radio Co., Ltd. 3 Nearest Address Bus Address Figure Figure

Claims (1)

[Claims] R for audio data storage externally connected to audio solid-state recording and playback IC
With the capacity recognition method that recognizes the capacity of AM, in advance,
An area where specific data indicating that the memory capacity has been checked is written to the first and second addresses of the RAM, and an area where the third address is written.
An area for writing memory capacity data is secured at the second address, and at the time of initial operation, the I
The capacity of each connected RAM is recognized by access from C, and specific data indicating that the memory capacity has been checked is written to the first and second addresses, and memory capacity data is written to the third address. In a RAM in which specific data indicating that the memory capacity has been checked has already been written to the first and second addresses, and memory capacity data has been written to the third address, the capacity can be recognized by reading these data. A method for recognizing the capacity of an externally connected RAM.