在该例程中，我们将使用DSP/BIOS内核提供的PIPE管道操作来完成数据传递。在DSP/BIOS配置工具中创建两个PIP对象连接接收中断与处理函数线程的pipRx管道，以及连接发送中断与处理函数线程的pipTx管道。

下面给出了pipe_audio.c完整的程序清单。当在评估板上运行该例程时，输入的语音信号会立即送到耳机中

* Copyright 2003 by Texas Instruments Incorporated.

* All rights reserved. Property of Texas Instruments Incorporated.

* Restricted rights to use, duplicate or disclose this code are

* granted through contract.

*

*/

/* "@(#) DDK 1.10.00.23 07-02-03 (ddk-b12)" */

/*

* ======== pip_audio.c ========

*

* This example demonstrates the use of IOM drivers with PIPs using

* the PIO adapter with a user defined device mini-driver called

* "udevCodec". The application performs a loopback. That is, audio data is

* read from one PIP connected to an input IOM channel, and the data is

* written back out on a PIP connected to an output IOM channel.

*

* The following objects need to be created in the DSP/BIOS

* configuration for this application:

*

* * A UDEV object, which links in a user device driver. In this case

* the UDEV is a codec based IOM device driver.

*

* * A SWI object named swiEcho. Configure the function as _echo,

* and the mailbox value as 3.

*

* * 2 PIP objects, one named pipTx, the other pipRx. The length of the

* buffers should be the same and can be any size. See the comments

* by the declarations below of pipTx and pipRx for the writer and

* reader notify function settings.

*

* * A LOG object named trace, used for status and debug output. Can be

* any size and can be circular or fixed.

*/

#include <std.h>

#include <log.h>

#include <pip.h>

#include <swi.h>

#include <sys.h>

#include <iom.h>

#include <pio.h>

#ifdef _6x_

extern far LOG_Obj trace;

extern far PIP_Obj pipRx;

extern far PIP_Obj pipTx;

extern far SWI_Obj swiEcho;

#else

extern LOG_Obj trace;

extern PIP_Obj pipRx;

extern PIP_Obj pipTx;

extern SWI_Obj swiEcho;

#endif

/*

* pioRx and pioTx objects will be initialized by PIO_new().

*/

PIO_Obj pioRx, pioTx;

/*

* ======== main ========

*

* Application startup funtion called by DSP/BIOS. Initialize the

* PIO adapter then return back into DSP/BIOS.

*/

main()

{

/*

* Initialize PIO module

*/

PIO_init();

/* Bind the PIPs to the channels using the PIO class drivers */

PIO_new(&pioRx, &pipRx, "/udevCodec", IOM_INPUT, NULL);

PIO_new(&pioTx, &pipTx, "/udevCodec", IOM_OUTPUT, NULL);

/*

* Prime the transmit side with buffers of silence.

* The transmitter should be started before the receiver.

* This results in input-to-output latency being one full

* buffer period if the pipes is configured for 2 frames.

*/

PIO_txStart(&pioTx, PIP_getWriterNumFrames(&pipTx), 0);

/* Prime the receive side with empty buffers to be filled. */

PIO_rxStart(&pioRx, PIP_getWriterNumFrames(&pipRx));

LOG_printf(&trace, "pip_audio started");

}

/*

* ======== echo ========

*

* This function is called by the swiEcho DSP/BIOS SWI thread created

* statically with the DSP/BIOS configuration tool. The PIO adapter

* posts the swi when an the input PIP has a buffer of data and the

* output PIP has an empty buffer to put new data into. This function

* copies from the input PIP to the output PIP. You could easily

* replace the copy function with a signal processing algorithm.

*/

Void echo(Void)

{

Int i, size;

unsigned short *src, *dst;

/*

* Check that the precondions are met, that is pipRx has a buffer of

* data and pipTx has a free buffer.

*/

if (PIP_getReaderNumFrames(&pipRx) <= 0) {

LOG_error("echo: No reader frame!", 0);

return;

}

if (PIP_getWriterNumFrames(&pipTx) <= 0) {

LOG_error("echo: No writer frame!", 0);

return;

}

/* get the full buffer from the receive PIP */

PIP_get(&pipRx);

src = PIP_getReaderAddr(&pipRx);

size = PIP_getReaderSize(&pipRx) * sizeof(short);

/* get the empty buffer from the transmit PIP */

PIP_alloc(&pipTx);

dst = PIP_getWriterAddr(&pipTx);

/* Do the data move. */

for (i = 0; i < size; i++) {

*dst++ = *src++;

}

/* Record the amount of actual data being sent */

PIP_setWriterSize(&pipTx, PIP_getReaderSize(&pipRx));

/* Free the receive buffer, put the transmit buffer */

PIP_put(&pipTx);

PIP_free(&pipRx);

}

程序源代码如下：

1．pip_audiocfg.h代码

/* Do *not* directly modify this file. It was */

/* generated by the Configuration Tool; any */

/* changes risk being overwritten. */

/* INPUT pip_audio.cdb */

#define CHIP_DM642 1

/* Include Header Files */

#include <std.h>

#include <hst.h>

#include <swi.h>

#include <log.h>

#include <pip.h>

#include <sts.h>

#ifdef __cplusplus

extern "C" {

#endif

extern far HST_Obj RTA_fromHost;

extern far HST_Obj RTA_toHost;

extern far SWI_Obj swiEcho;

extern far LOG_Obj LOG_system;

extern far LOG_Obj trace;

extern far PIP_Obj pipRx;

extern far PIP_Obj pipTx;

extern far STS_Obj IDL_busyObj;

extern far void CSL_cfgInit();

#ifdef __cplusplus

}

#endif /* extern "C" */

2．pip_audiocfg_c.c代码

/* Do *not* directly modify this file. It was */

/* generated by the Configuration Tool; any */

/* changes risk being overwritten. */

/* INPUT pip_audio.cdb */

/* Include Header File */

#include "pip_audiocfg.h"

#ifdef __cplusplus

#pragma CODE_SECTION(".text:CSL_cfgInit")

#else

#pragma CODE_SECTION(CSL_cfgInit,".text:CSL_cfgInit")

#endif

#ifdef __cplusplus

#pragma FUNC_EXT_CALLED()

#else

#pragma FUNC_EXT_CALLED(CSL_cfgInit)

#endif

/* Config Structures */

/* Handles */

/*

* ======== CSL_cfgInit() ========

*/

void CSL_cfgInit()

{

}

3．evmdm642_codec_devParams.c代码

/*

* Copyright 2003 by Texas Instruments Incorporated.

* All rights reserved. Property of Texas Instruments Incorporated.

* Restricted rights to use, duplicate or disclose this code are

* granted through contract.

*

*/

/* "@(#) DDK 1.10.00.23 07-02-03 (ddk-b12)" */

/*

* ======== evmdm642_devParams.c ========

* EVMDM642_EDMA_AIC23 default driver parameters

*/

#include <std.h>

#include <evmdm642_edma_aic23.h>

/*

* ======== EVMDM642_DEVPARAMS ========

* This static initialization defines the default parameters used for

* EVMDM642_EDMA_AIC23 IOM driver

*/

EVMDM642_EDMA_AIC23_DevParams EVMDM642_CODEC_DEVPARAMS =

EVMDM642_EDMA_AIC23_DEFAULT_DEVPARAMS;

4．pip_audio.c代码

/*

* Copyright 2003 by Texas Instruments Incorporated.

* All rights reserved. Property of Texas Instruments Incorporated.

* Restricted rights to use, duplicate or disclose this code are

* granted through contract.

*

*/

/* "@(#) DDK 1.10.00.23 07-02-03 (ddk-b12)" */

/*

* ======== pip_audio.c ========

*

* This example demonstrates the use of IOM drivers with PIPs using

* the PIO adapter with a user defined device mini-driver called

* "udevCodec". The application performs a loopback. That is, audio data is

* read from one PIP connected to an input IOM channel, and the data is

* written back out on a PIP connected to an output IOM channel.

*

* The following objects need to be created in the DSP/BIOS

* configuration for this application:

*

* * A UDEV object, which links in a user device driver. In this case

* the UDEV is a codec based IOM device driver.

*

* * A SWI object named swiEcho. Configure the function as _echo,

* and the mailbox value as 3.

*

* * 2 PIP objects, one named pipTx, the other pipRx. The length of the

* buffers should be the same and can be any size. See the comments

* by the declarations below of pipTx and pipRx for the writer and

* reader notify function settings.

*

* * A LOG object named trace, used for status and debug output. Can be

* any size and can be circular or fixed.

*/

#include <std.h>

#include <log.h>

#include <pip.h>

#include <swi.h>

#include <sys.h>

#include <iom.h>

#include <pio.h>

#ifdef _6x_

extern far LOG_Obj trace;

extern far PIP_Obj pipRx;

extern far PIP_Obj pipTx;

extern far SWI_Obj swiEcho;

#else

extern LOG_Obj trace;

extern PIP_Obj pipRx;

extern PIP_Obj pipTx;

extern SWI_Obj swiEcho;

#endif

/*

* pioRx and pioTx objects will be initialized by PIO_new().

*/

PIO_Obj pioRx, pioTx;

/*

* ======== main ========

*

* Application startup funtion called by DSP/BIOS. Initialize the

* PIO adapter then return back into DSP/BIOS.

*/

main()

{

/*

* Initialize PIO module

*/

PIO_init();

/* Bind the PIPs to the channels using the PIO class drivers */

PIO_new(&pioRx, &pipRx, "/udevCodec", IOM_INPUT, NULL);

PIO_new(&pioTx, &pipTx, "/udevCodec", IOM_OUTPUT, NULL);

/*

* Prime the transmit side with buffers of silence.

* The transmitter should be started before the receiver.

* This results in input-to-output latency being one full

* buffer period if the pipes is configured for 2 frames.

*/

PIO_txStart(&pioTx, PIP_getWriterNumFrames(&pipTx), 0);

/* Prime the receive side with empty buffers to be filled. */

PIO_rxStart(&pioRx, PIP_getWriterNumFrames(&pipRx));

LOG_printf(&trace, "pip_audio started");

}

/*

* ======== echo ========

*

* This function is called by the swiEcho DSP/BIOS SWI thread created

* statically with the DSP/BIOS configuration tool. The PIO adapter

* posts the swi when an the input PIP has a buffer of data and the

* output PIP has an empty buffer to put new data into. This function

* copies from the input PIP to the output PIP. You could easily

* replace the copy function with a signal processing algorithm.

*/

Void echo(Void)

{

Int i, size;

unsigned short *src, *dst;

/*

* Check that the precondions are met, that is pipRx has a buffer of

* data and pipTx has a free buffer.

*/

if (PIP_getReaderNumFrames(&pipRx) <= 0)

{

LOG_error("echo: No reader frame!", 0);

return;

}

if (PIP_getWriterNumFrames(&pipTx) <= 0)

{

LOG_error("echo: No writer frame!", 0);

return;

}

/* get the full buffer from the receive PIP */

PIP_get(&pipRx);

src = PIP_getReaderAddr(&pipRx);

size = PIP_getReaderSize(&pipRx) * sizeof(short);

/* get the empty buffer from the transmit PIP */

PIP_alloc(&pipTx);

dst = PIP_getWriterAddr(&pipTx);

/* Do the data move. */

for (i = 0; i < size; i++)

{

*dst++ = *src++;

}

/* Record the amount of actual data being sent */

PIP_setWriterSize(&pipTx, PIP_getReaderSize(&pipRx));

/* Free the receive buffer, put the transmit buffer */

PIP_put(&pipTx);

PIP_free(&pipRx);

}