JPH0385098A - Audio equipment with dsp - Google Patents

Abstract

PURPOSE:To attain the output of audio data at a high speed by using a parallel data input output terminal for external RAM connection of a digital signal processor as audio data output terminal. CONSTITUTION:When the audio data is inputted from a DSP(digital signal processor) serial terminal TSi, an S/P interface 11a receives serial dat sequentially, converts it into a parallel data, which is outputted onto a data bus. An arithmetic section 11e fetches an audio data on a bus and applies prescribed DSP processing. Then the arithmetic section 11e outputs the result of processing from a parallel input output terminal TPio via a parallel interface 11d. Through the constitution above, since the access of delay use external RAM 14 is implemented at a speed of being a multiple of 20 or over with respect to the sampling frequency, high speed output is attained.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to an audio device equipped with a DSP.

In particular, the present invention relates to an audio device capable of outputting parallel data at high speed from a serial-in/serial-out type DSP.

<Prior art> A DSP (digital signal processor) performs predetermined processing on digital audio data, such as volume adjustment processing, left and right channel separation processing, high cut processing, equalization processing, bass/treble processing, loudness processing, etc. The result is output to an audio circuit including a DA converter and the like in the subsequent stage.

Such audio DSPs include serial-in/serial-out type DSPs. Figure 2 is a block diagram of the main parts of an audio device equipped with a serial-in/serial-out type DSP. 1 is a DSP with serial-in/serial-out terminals and parallel input/output terminals for connecting external RAM for delay. have. 2 is a digital source that outputs audio data serially, 3 is a DS
A DA converter converts the processing result of P into parallel and then converts it into an analog signal, and 4 is an external RAM for delay.

<Problems to be solved by the invention> In conventional serial-in/serial-out type DSPs, data can only be input and output serially, and the output is basically synchronized with the input at the sampling frequency fs.
I could only output it with .

For this reason, conventionally it was not possible to output DSP processing results at high speed,
Accurate processing results from the subsequent audio circuit, e.g.
A problem arises in that the A conversion result cannot be obtained. For example, even if it is possible to interpolate a large number of audio data between input audio data through DSP processing, these interpolated data cannot be output to the DA converter 3 at high speed, and in the end, it is difficult to obtain A conversion results with good accuracy. The problem arises that it cannot be done.

General-purpose DSPs with parallel input/output ports have recently become commercially available, but the data format is different from that of audio data (2' binary), and large-scale peripheral circuits are required to synchronize the data. However, it was difficult to use it for audio purposes.

From the above, an object of the present invention is to provide an audio device equipped with a DSP that can output parallel data at high speed using a serial-in/serial-out type DSP.

Means for Solving the Problems> In the present invention, in order to use the parallel input/output terminal for external RAM connection in a serial-in/serial-out type DSP as an audio data output terminal, the processing result of the DSP is This is achieved by means for sequentially outputting certain audio data to the terminal, and means for performing predetermined audio processing on the output data.

<Function> The parallel data input/output terminal for external RAM connection in a serial-in/serial-out type DSP is used as an audio data output terminal.

Audio data, which is the processing result of the DSP, is sequentially output to the terminal via the parallel interface.

Executing Predetermined Audio Processing on Output Data 6 (Embodiment) FIG. 1 is a block diagram of the main parts of an audio device equipped with a DSP according to the present invention. 11 is a DSP with serial in/serial out terminals TSi, TSo and external R for delay.
It has a parallel input/output terminal PTio for AM connection. 12 is a digital source that outputs audio data serially; 13 is a microcomputer that loads processing programs and various parameters into the DSP when the power is turned on; 14 is a RAM for external connection for delay; and 15 is a device that receives DSP processing results in parallel. a latch circuit for storing; 16 is a D for converting data stored in the latch circuit into an analog signal;
It is an A converter.

In the DSP, lla and llb are terminals T S l g
11c is a serial interface that converts the serial data input from TSi into parallel data and outputs it to bus BUS. 11c is a serial interface that takes in parallel data on the bus, converts it to serial data, and outputs it from terminal TSo. 11d is a bus A parallel interface that takes in the above parallel data and outputs it directly from the terminal TPio in parallel at high speed, 11e is the arithmetic unit, llf
is R that stores programs, parameters, processing results, etc.
It is AM.

Below, serial terminal TSo or parallel input/output terminal T
A case where an audio circuit including a DA converter is connected to each PIO will be explained separately.

(a) When an audio circuit including a DA converter is connected to the serial terminal TSo: In this case, the processing program loaded from the microcomputer 13 sequentially varies the processing results when predetermined DSP processing is performed on the audio data. Siri interface ll
It is configured to transfer to c.

When the power is turned on, processing programs and various parameters are loaded into the RAM 11f of the DSpH. This enables the calculation unit lie to perform DSP processing according to the processing program.

In such a state, when audio data is input from the serial terminal TSi, the serial interface lla
receives serial data sequentially in synchronization with a clock having a frequency of 16·fs (16 is the data bit length, fs is the sampling frequency of audio data), converts it into parallel data, and outputs it onto the data bus. The arithmetic unit lie takes in audio data appearing on the bus and applies predetermined DSP processing to the data according to a processing program.

The processing results are transferred to the remote interface ILc.

Para-serial interface 1.1c converts the audio data that is the processing result into serial data, and
・Output to the audio circuit bit serially in synchronization with the fs clock.

Thereafter, processing similar to the above is performed on all audio data.

(b) Latch circuit 15- to parallel input/output terminal FTio
When an audio circuit including the DA converter 16 is connected: In such a case, when the processing program loaded from the microcomputer 13 performs predetermined DSP processing on the audio data, the processing results are sequentially transferred to the parallel interface li.
d at high speed, for example, at a frequency of 16 fs.

When the power is turned on, processing programs and various parameters are loaded into the RAM 11f of the DSPII. As a result, the arithmetic unit lie executes the DSP according to the processing program.
processing becomes possible.

In such a state, when audio data is input from the serial terminal TSi, the serial interface lla
receives serial data sequentially in synchronization with a clock with a frequency of 16 fs, converts it into parallel data, and outputs it onto the data bus.

The arithmetic unit lie takes in audio data appearing on the bus and applies predetermined DSP processing to the data according to a processing program. For example, a large number (16 pieces) of audio data is interpolated between audio data. After that, the calculation unit lie sends the processing results to the parallel input/output terminal TP via the parallel interface lid at a cycle of 16 fs.
Output from io. What is the reason why such high-speed output is possible?

Audio serial in/serial out type D
This is because the SP is configured so that the delay external RAML 4 can be accessed at a speed 20 times faster than the sampling frequency fs.

The high-speed parallel data output to the parallel input/output terminals TPi, o is stored in the latch circuit 15, and then input to the DA converter 16, where it is converted into an analog signal and output.

Thereafter, processing similar to the above is performed on all audio data.

<Effects of the Invention> According to the present invention, since the parallel input/output terminal of the delay external RAM in the serial-in/serial-out type audio DSP is configured to be the audio data output terminal, data can be transmitted from the terminal at high speed. Audio data can be output, and therefore, predetermined audio processing can be performed on these high-speed audio data at a subsequent stage, and highly accurate processing results can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an audio device with a DSP according to the present invention, and FIG. 2 is a block diagram of a conventional audio device with a DSP. 11...DSP lid...Parallel interface 14...External RAM for delay 15...Latch circuit 16...DA converter TSi...Serial in terminal TSo...Serial out terminal TPio...Parallel input/output terminal

Claims (1)

[Scope of Claims] An audio device equipped with a serial-in/serial-out type DSP that performs predetermined processing on serially input audio data and outputs the processed audio data in serial, comprising: an external RAM in the DSP; The parallel data input/output terminal for connection is used as an audio data output terminal, and the DSP
An audio device equipped with a DSP, which sequentially outputs audio data as a processing result to the terminal via a parallel interface, and performs predetermined audio processing on the output data.