Sheldon Cooper / Mbed 2 deprecated USBAudioToI2S

Plays USB Audio packets through external DAC (Cirrus Logic CS4344). Simple demo code, don't expect a sophisticated I2S library. HW setup: mbed DIP 5 (I2STX_SDA) -> DAC SDIN (Serial Audio Data Input) mbed DIP 6 (I2STX_WS) -> DAC LRCK (Left Right Clock) mbed DIP 7 (I2STX_CLK) -> DAC SCLK (External Serial Clock Input) mbed DIP 30 (I2SRX_CLK) -> DAC MCLK (Master Clock) also needed an extra USB connector wired to mbed. Does not work with built-in USB. Code needs a bit of clean up.

Dependencies:   mbed

main.cpp

Committer:
csorbag
Date:
2012-04-16
Revision:
1:12e8ee1b7ea2
Parent:
0:bf9e7b99dda5

File content as of revision 1:12e8ee1b7ea2:

#include "mbed.h"
#include "USBAudio.h"
#include "I2S.h"

Serial pc(USBTX, USBRX);

// frequency: 48 kHz
#define FREQ 48000

// 1 channel: mono
#define NB_CHA 2

// length of an audio packet: each ms, we receive 48 * 16bits ->48 * 2 bytes per channel. For stereo multiply by 2 
#define AUDIO_LENGTH_PACKET 48 * 2 * 2

// USBAudio
USBAudio audio(FREQ, NB_CHA,FREQ, NB_CHA,0x7bb8, 0x1112);

int main() {
    int16_t buf[AUDIO_LENGTH_PACKET/2];
    
    
    setup(&pc);
    
    while (1) {
        // read an audio packet
        audio.read((uint8_t *)buf);

        // send to DAC
        play(buf,AUDIO_LENGTH_PACKET/2);
    }
}