T T / Mbed 2 deprecated USBAudioUDA1345

96kHz-16bit USB Audio Output interface with UDA1345 and 24.576MHz Xtal.

Dependencies:   I2S USBDevice mbed

Fork of USBAudioPlayback by Samuel Mokrani

main.cpp@4:a3aee5fc768a, 2014-02-04 (annotated)

Committer:
edy555
Date:
Tue Feb 04 15:35:52 2014 +0000
Revision:
4:a3aee5fc768a
Parent:
3:44343b9dd8b6
Child:
5:ca2316551f3d
remote input channel, reduce buffer size, change used api from readWrite to read

Who changed what in which revision?

UserRevisionLine numberNew contents of line
samux 0:eb53799c0b97 1 // Playback example with the USBAUDIO library
samux 0:eb53799c0b97 2
samux 0:eb53799c0b97 3 #include "mbed.h"
samux 0:eb53799c0b97 4 #include "USBAudio.h"
edy555 3:44343b9dd8b6 5 #include "I2S.h"
samux 0:eb53799c0b97 6
samux 0:eb53799c0b97 7 // frequency: 48 kHz
edy555 3:44343b9dd8b6 8 #define FREQ_SPK 96000
edy555 3:44343b9dd8b6 9 #define FREQ_MIC 8000
samux 0:eb53799c0b97 10
samux 0:eb53799c0b97 11 // 2channels: stereo
samux 0:eb53799c0b97 12 #define NB_CHA_SPK 2
edy555 4:a3aee5fc768a 13 #define NB_CHA_MIC 0
samux 0:eb53799c0b97 14
samux 0:eb53799c0b97 15 // length computed: each ms, we receive 48 * 16bits ->48 * 2 bytes. as there are two channels, the length will be 48 * 2 * 2
samux 0:eb53799c0b97 16 #define LENGTH_AUDIO_PACKET_SPK (FREQ_SPK / 500) * NB_CHA_SPK
samux 0:eb53799c0b97 17 #define LENGTH_AUDIO_PACKET_MIC (FREQ_MIC / 500) * NB_CHA_MIC
samux 0:eb53799c0b97 18
samux 0:eb53799c0b97 19 // USBAudio object
samux 0:eb53799c0b97 20 USBAudio audio(FREQ_SPK, NB_CHA_SPK, FREQ_MIC, NB_CHA_MIC, 0xab45, 0x0378);
samux 0:eb53799c0b97 21
edy555 3:44343b9dd8b6 22 DigitalOut myled(LED1);
edy555 3:44343b9dd8b6 23
edy555 3:44343b9dd8b6 24 I2S i2s(I2S_TRANSMIT, p5, p6, p7);
edy555 3:44343b9dd8b6 25 I2S i2srx(I2S_RECEIVE, p8, p29, p15);
edy555 3:44343b9dd8b6 26
edy555 4:a3aee5fc768a 27 #define CHUNKS 6
edy555 3:44343b9dd8b6 28
edy555 3:44343b9dd8b6 29 int buf_out[LENGTH_AUDIO_PACKET_MIC/sizeof(int)];
edy555 3:44343b9dd8b6 30 int16_t buf_in[CHUNKS][LENGTH_AUDIO_PACKET_SPK/sizeof(int16_t)];
edy555 3:44343b9dd8b6 31 int16_t * stream_in = NULL;
edy555 3:44343b9dd8b6 32 int16_t * stream_in_tail = NULL;
edy555 3:44343b9dd8b6 33 int read_pos = 0;
edy555 3:44343b9dd8b6 34 int write_pos = 0;
edy555 3:44343b9dd8b6 35
edy555 3:44343b9dd8b6 36 void genwave()
edy555 3:44343b9dd8b6 37 {
edy555 3:44343b9dd8b6 38 int buf[8];
edy555 3:44343b9dd8b6 39 if (stream_in == NULL) {
edy555 3:44343b9dd8b6 40 buf[0] = buf[1] = buf[2] = buf[3] = buf[4] = buf[5] = buf[6] = buf[7] = 0;
edy555 3:44343b9dd8b6 41 i2s.write(buf, 6);
edy555 3:44343b9dd8b6 42 return;
edy555 3:44343b9dd8b6 43 }
edy555 3:44343b9dd8b6 44
edy555 3:44343b9dd8b6 45 myled = 1;
edy555 3:44343b9dd8b6 46 buf[0] = stream_in[0];
edy555 3:44343b9dd8b6 47 buf[1] = stream_in[1];
edy555 3:44343b9dd8b6 48 buf[2] = stream_in[2];
edy555 3:44343b9dd8b6 49 buf[3] = stream_in[3];
edy555 3:44343b9dd8b6 50 buf[4] = stream_in[4];
edy555 3:44343b9dd8b6 51 buf[5] = stream_in[5];
edy555 3:44343b9dd8b6 52 buf[6] = stream_in[6];
edy555 3:44343b9dd8b6 53 buf[7] = stream_in[7];
edy555 3:44343b9dd8b6 54 i2s.write(buf, 8);
edy555 3:44343b9dd8b6 55 stream_in += 8;
edy555 3:44343b9dd8b6 56 if (stream_in >= stream_in_tail) {
edy555 3:44343b9dd8b6 57 write_pos++;
edy555 3:44343b9dd8b6 58 write_pos %= CHUNKS;
edy555 3:44343b9dd8b6 59 stream_in = buf_in[write_pos];
edy555 3:44343b9dd8b6 60 stream_in_tail = &buf_in[write_pos][LENGTH_AUDIO_PACKET_SPK/sizeof(int16_t)];
edy555 3:44343b9dd8b6 61 }
edy555 3:44343b9dd8b6 62 myled = 0;
edy555 3:44343b9dd8b6 63 }
edy555 3:44343b9dd8b6 64
samux 0:eb53799c0b97 65 int main() {
edy555 3:44343b9dd8b6 66 i2srx.masterslave(I2S_SLAVE);
edy555 3:44343b9dd8b6 67 i2srx.frequency(96000);
edy555 3:44343b9dd8b6 68 i2srx.start();
edy555 3:44343b9dd8b6 69 i2s.attach(genwave);
edy555 3:44343b9dd8b6 70 i2s.masterslave(I2S_MASTER);
edy555 3:44343b9dd8b6 71 i2s.wordsize(16);
edy555 3:44343b9dd8b6 72 i2s.frequency(96000);
edy555 3:44343b9dd8b6 73 i2s.set_interrupt_fifo_level(0);
edy555 3:44343b9dd8b6 74 i2s.start();
samux 0:eb53799c0b97 75
samux 0:eb53799c0b97 76 while (1) {
edy555 4:a3aee5fc768a 77 audio.read((uint8_t *)buf_in[read_pos++]);
edy555 3:44343b9dd8b6 78 read_pos %= CHUNKS;
edy555 3:44343b9dd8b6 79 if (stream_in == NULL && read_pos > CHUNKS / 2) {
edy555 3:44343b9dd8b6 80 stream_in = buf_in[write_pos];
edy555 3:44343b9dd8b6 81 stream_in_tail = &buf_in[write_pos][LENGTH_AUDIO_PACKET_SPK/sizeof(int16_t)];
edy555 3:44343b9dd8b6 82 }
samux 0:eb53799c0b97 83 }
samux 0:eb53799c0b97 84 }