main.cpp

00001 // Playback example with the USBAUDIO library
00002 
00003 #include "mbed.h"
00004 #include "USBAudio.h"
00005 
00006 // frequency: 48 kHz
00007 #define FREQ_SPK 48000
00008 #define FREQ_MIC 48000
00009 
00010 // 2channels: stereo
00011 #define NB_CHA_SPK 2
00012 #define NB_CHA_MIC 2
00013 
00014 // length computed: each ms, we receive 48 * 16bits ->48 * 2 bytes. as there are two channels, the length will be 48 * 2 * 2
00015 #define LENGTH_AUDIO_PACKET_SPK (FREQ_SPK / 500) * NB_CHA_SPK
00016 #define LENGTH_AUDIO_PACKET_MIC (FREQ_MIC / 500) * NB_CHA_MIC
00017 
00018 // USBAudio object
00019 USBAudio audio(FREQ_SPK, NB_CHA_SPK, FREQ_MIC, NB_CHA_MIC, 0xab45, 0x0378);
00020 
00021 int main() {
00022     // buffer of int
00023     int buf_in[LENGTH_AUDIO_PACKET_SPK/sizeof(int)];
00024     int buf_out[LENGTH_AUDIO_PACKET_MIC/sizeof(int)];
00025     int * stream_out = buf_in;
00026     int * stream_in = buf_out;
00027     int * tmp = NULL;
00028 
00029     while (1) {
00030         // read and write one audio packet each frame
00031         audio.readWrite((uint8_t *)stream_in, (uint8_t *)stream_out);
00032         
00033         // swap the buffers
00034         tmp = stream_in;
00035         stream_in = stream_out;
00036         stream_out = tmp;
00037     }
00038 }
00039 
00040