audioFX

library for blackfin audio FX board

An audio demo of a pedal made using this code can be found here The code running in the above video is this example

This is code for creating audio effects on BF70x Blackfin+ DSP chips. A Blackfin+ processor and an I2S DAC are required. This library currently supports both the AK4558 (recommended) and the ADAU17x1.

Audio buffers are handled via DMA and a callback function is specified when a buffer of data is ready to be processed. A simple gain example is shown here:

#include "audioFX.h"
#include "ak4558.h"

ak4558 iface;

/*this function will be called when there is a new buffer of data ready
 * to be processed. Make sure not to block in here!
 */
void audioLoop(int32_t *data)
{
	for(int i=0; i<AUDIO_BUFSIZE; i++){
		*data++ = *data / 2;
		*data++ = *data / 2;
	}
}

// the setup function runs once when you press reset or power the board
void setup() {
	iface.begin();

	fx.begin();

	//set the function to be called when a buffer is ready
	fx.setHook(audioLoop);
}

// the loop function runs over and over again forever
void loop() {
	__asm__ volatile ("IDLE;");
}

Note that some examples in this library are currently obsolete and need to be updated to reflect changes to the library.

Dependencies

This code depends on:

• GNU toolchain for blackfin+
• BF706 header files
• Blackfin+ Arduino Core