USBAudio example using a microphone

Dependencies:   USBDevice mbed

Files at this revision

API Documentation at this revision

Comitter:
samux
Date:
Tue Dec 20 10:44:10 2011 +0000
Parent:
4:bef3b485f22e
Child:
6:be128039be16
Commit message:
doesn\'t work but cleaning up...

Changed in this revision

FATFileSystem.lib Show diff for this revision Revisions of this file
SDFileSystem/.lib Show diff for this revision Revisions of this file
SDFileSystem/SDFileSystem.cpp Show diff for this revision Revisions of this file
SDFileSystem/SDFileSystem.h Show diff for this revision Revisions of this file
USBDevice/USBAudio/USBAudio.cpp Show annotated file Show diff for this revision Revisions of this file
USBDevice/USBAudio/USBAudio.h Show annotated file Show diff for this revision Revisions of this file
USBDevice/USBAudio/USBAudio_Types.h Show annotated file Show diff for this revision Revisions of this file
main.cpp Show annotated file Show diff for this revision Revisions of this file
--- a/FATFileSystem.lib	Mon Dec 19 16:13:32 2011 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,1 +0,0 @@
-http://mbed.co.uk/projects/libraries/svn/FATFileSystem/trunk@26
\ No newline at end of file
--- a/SDFileSystem/.lib	Mon Dec 19 16:13:32 2011 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,1 +0,0 @@
-http://mbed.org/users/simon/programs/SDFileSystem/5yj8f
\ No newline at end of file
--- a/SDFileSystem/SDFileSystem.cpp	Mon Dec 19 16:13:32 2011 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,457 +0,0 @@
-/* mbed SDFileSystem Library, for providing file access to SD cards
- * Copyright (c) 2008-2010, sford
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
-/* Introduction
- * ------------
- * SD and MMC cards support a number of interfaces, but common to them all
- * is one based on SPI. This is the one I'm implmenting because it means
- * it is much more portable even though not so performant, and we already 
- * have the mbed SPI Interface!
- *
- * The main reference I'm using is Chapter 7, "SPI Mode" of: 
- *  http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf
- *
- * SPI Startup
- * -----------
- * The SD card powers up in SD mode. The SPI interface mode is selected by
- * asserting CS low and sending the reset command (CMD0). The card will 
- * respond with a (R1) response.
- *
- * CMD8 is optionally sent to determine the voltage range supported, and 
- * indirectly determine whether it is a version 1.x SD/non-SD card or 
- * version 2.x. I'll just ignore this for now.
- *
- * ACMD41 is repeatedly issued to initialise the card, until "in idle"
- * (bit 0) of the R1 response goes to '0', indicating it is initialised.
- *
- * You should also indicate whether the host supports High Capicity cards,
- * and check whether the card is high capacity - i'll also ignore this
- *
- * SPI Protocol
- * ------------
- * The SD SPI protocol is based on transactions made up of 8-bit words, with
- * the host starting every bus transaction by asserting the CS signal low. The
- * card always responds to commands, data blocks and errors.
- * 
- * The protocol supports a CRC, but by default it is off (except for the 
- * first reset CMD0, where the CRC can just be pre-calculated, and CMD8)
- * I'll leave the CRC off I think! 
- * 
- * Standard capacity cards have variable data block sizes, whereas High 
- * Capacity cards fix the size of data block to 512 bytes. I'll therefore
- * just always use the Standard Capacity cards with a block size of 512 bytes.
- * This is set with CMD16.
- *
- * You can read and write single blocks (CMD17, CMD25) or multiple blocks 
- * (CMD18, CMD25). For simplicity, I'll just use single block accesses. When
- * the card gets a read command, it responds with a response token, and then 
- * a data token or an error.
- * 
- * SPI Command Format
- * ------------------
- * Commands are 6-bytes long, containing the command, 32-bit argument, and CRC.
- *
- * +---------------+------------+------------+-----------+----------+--------------+
- * | 01 | cmd[5:0] | arg[31:24] | arg[23:16] | arg[15:8] | arg[7:0] | crc[6:0] | 1 |
- * +---------------+------------+------------+-----------+----------+--------------+
- *
- * As I'm not using CRC, I can fix that byte to what is needed for CMD0 (0x95)
- *
- * All Application Specific commands shall be preceded with APP_CMD (CMD55).
- *
- * SPI Response Format
- * -------------------
- * The main response format (R1) is a status byte (normally zero). Key flags:
- *  idle - 1 if the card is in an idle state/initialising 
- *  cmd  - 1 if an illegal command code was detected
- *
- *    +-------------------------------------------------+
- * R1 | 0 | arg | addr | seq | crc | cmd | erase | idle |
- *    +-------------------------------------------------+
- *
- * R1b is the same, except it is followed by a busy signal (zeros) until
- * the first non-zero byte when it is ready again.
- *
- * Data Response Token
- * -------------------
- * Every data block written to the card is acknowledged by a byte 
- * response token
- *
- * +----------------------+
- * | xxx | 0 | status | 1 |
- * +----------------------+
- *              010 - OK!
- *              101 - CRC Error
- *              110 - Write Error
- *
- * Single Block Read and Write
- * ---------------------------
- *
- * Block transfers have a byte header, followed by the data, followed
- * by a 16-bit CRC. In our case, the data will always be 512 bytes.
- *  
- * +------+---------+---------+- -  - -+---------+-----------+----------+
- * | 0xFE | data[0] | data[1] |        | data[n] | crc[15:8] | crc[7:0] | 
- * +------+---------+---------+- -  - -+---------+-----------+----------+
- */
- 
-#include "SDFileSystem.h"
-
-#define SD_COMMAND_TIMEOUT 5000
-
-SDFileSystem::SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name) :
-  FATFileSystem(name), _spi(mosi, miso, sclk), _cs(cs) {
-      _cs = 1; 
-}
-
-#define R1_IDLE_STATE           (1 << 0)
-#define R1_ERASE_RESET          (1 << 1)
-#define R1_ILLEGAL_COMMAND      (1 << 2)
-#define R1_COM_CRC_ERROR        (1 << 3)
-#define R1_ERASE_SEQUENCE_ERROR (1 << 4)
-#define R1_ADDRESS_ERROR        (1 << 5)
-#define R1_PARAMETER_ERROR      (1 << 6)
-
-// Types
-//  - v1.x Standard Capacity
-//  - v2.x Standard Capacity
-//  - v2.x High Capacity
-//  - Not recognised as an SD Card
-
-#define SDCARD_FAIL 0
-#define SDCARD_V1   1
-#define SDCARD_V2   2
-#define SDCARD_V2HC 3
-
-int SDFileSystem::initialise_card() {
-    // Set to 100kHz for initialisation, and clock card with cs = 1
-    _spi.frequency(100000); 
-    _cs = 1;
-    for(int i=0; i<16; i++) {   
-        _spi.write(0xFF);
-    }
-
-    // send CMD0, should return with all zeros except IDLE STATE set (bit 0)
-    if(_cmd(0, 0) != R1_IDLE_STATE) { 
-        fprintf(stderr, "No disk, or could not put SD card in to SPI idle state\n");
-        return SDCARD_FAIL;
-    }
-
-    // send CMD8 to determine whther it is ver 2.x
-    int r = _cmd8();
-    if(r == R1_IDLE_STATE) {
-        return initialise_card_v2();
-    } else if(r == (R1_IDLE_STATE | R1_ILLEGAL_COMMAND)) {
-        return initialise_card_v1();
-    } else {
-        fprintf(stderr, "Not in idle state after sending CMD8 (not an SD card?)\n");
-        return SDCARD_FAIL;
-    }
-}
-
-int SDFileSystem::initialise_card_v1() {
-    for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
-        _cmd(55, 0); 
-        if(_cmd(41, 0) == 0) { 
-            return SDCARD_V1;
-        }
-    }
-
-    fprintf(stderr, "Timeout waiting for v1.x card\n");
-    return SDCARD_FAIL;
-}
-
-int SDFileSystem::initialise_card_v2() {
-    
-    for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
-        _cmd(55, 0); 
-        if(_cmd(41, 0) == 0) { 
-            _cmd58();
-            return SDCARD_V2;
-        }
-    }
-
-    fprintf(stderr, "Timeout waiting for v2.x card\n");
-    return SDCARD_FAIL;
-}
-
-int SDFileSystem::disk_initialize() {
-
-    int i = initialise_card();
-//    printf("init card = %d\n", i);
-//    printf("OK\n");
-
-    _sectors = _sd_sectors();
-
-    // Set block length to 512 (CMD16)
-    if(_cmd(16, 512) != 0) {
-        fprintf(stderr, "Set 512-byte block timed out\n");
-        return 1;
-    }
-        
-    _spi.frequency(1000000); // Set to 1MHz for data transfer
-    return 0;
-}
-
-int SDFileSystem::disk_write(const char *buffer, int block_number) {
-    // set write address for single block (CMD24)
-    if(_cmd(24, block_number * 512) != 0) {
-        return 1;
-    }
-
-    // send the data block
-    _write(buffer, 512);    
-    return 0;    
-}
-
-int SDFileSystem::disk_read(char *buffer, int block_number) {        
-    // set read address for single block (CMD17)
-    if(_cmd(17, block_number * 512) != 0) {
-        return 1;
-    }
-    
-    // receive the data
-    _read(buffer, 512);
-    return 0;
-}
-
-int SDFileSystem::disk_status() { return 0; }
-int SDFileSystem::disk_sync() { return 0; }
-int SDFileSystem::disk_sectors() { return _sectors; }
-
-// PRIVATE FUNCTIONS
-
-int SDFileSystem::_cmd(int cmd, int arg) {
-    _cs = 0; 
-
-    // send a command
-    _spi.write(0x40 | cmd);
-    _spi.write(arg >> 24);
-    _spi.write(arg >> 16);
-    _spi.write(arg >> 8);
-    _spi.write(arg >> 0);
-    _spi.write(0x95);
-
-    // wait for the repsonse (response[7] == 0)
-    for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
-        int response = _spi.write(0xFF);
-        if(!(response & 0x80)) {
-            _cs = 1;
-            _spi.write(0xFF);
-            return response;
-        }
-    }
-    _cs = 1;
-    _spi.write(0xFF);
-    return -1; // timeout
-}
-int SDFileSystem::_cmdx(int cmd, int arg) {
-    _cs = 0; 
-
-    // send a command
-    _spi.write(0x40 | cmd);
-    _spi.write(arg >> 24);
-    _spi.write(arg >> 16);
-    _spi.write(arg >> 8);
-    _spi.write(arg >> 0);
-    _spi.write(0x95);
-
-    // wait for the repsonse (response[7] == 0)
-    for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
-        int response = _spi.write(0xFF);
-        if(!(response & 0x80)) {
-            return response;
-        }
-    }
-    _cs = 1;
-    _spi.write(0xFF);
-    return -1; // timeout
-}
-
-
-int SDFileSystem::_cmd58() {
-    _cs = 0; 
-    int arg = 0;
-    
-    // send a command
-    _spi.write(0x40 | 58);
-    _spi.write(arg >> 24);
-    _spi.write(arg >> 16);
-    _spi.write(arg >> 8);
-    _spi.write(arg >> 0);
-    _spi.write(0x95);
-
-    // wait for the repsonse (response[7] == 0)
-    for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
-        int response = _spi.write(0xFF);
-        if(!(response & 0x80)) {
-            int ocr = _spi.write(0xFF) << 24;
-            ocr |= _spi.write(0xFF) << 16;
-            ocr |= _spi.write(0xFF) << 8;
-            ocr |= _spi.write(0xFF) << 0;
-//            printf("OCR = 0x%08X\n", ocr);
-            _cs = 1;
-            _spi.write(0xFF);
-            return response;
-        }
-    }
-    _cs = 1;
-    _spi.write(0xFF);
-    return -1; // timeout
-}
-
-int SDFileSystem::_cmd8() {
-    _cs = 0; 
-    
-    // send a command
-    _spi.write(0x40 | 8); // CMD8
-    _spi.write(0x00);     // reserved
-    _spi.write(0x00);     // reserved
-    _spi.write(0x01);     // 3.3v
-    _spi.write(0xAA);     // check pattern
-    _spi.write(0x87);     // crc
-
-    // wait for the repsonse (response[7] == 0)
-    for(int i=0; i<SD_COMMAND_TIMEOUT * 1000; i++) {
-        char response[5];
-        response[0] = _spi.write(0xFF);
-        if(!(response[0] & 0x80)) {
-                for(int j=1; j<5; j++) {
-                    response[i] = _spi.write(0xFF);
-                }
-                _cs = 1;
-                _spi.write(0xFF);
-                return response[0];
-        }
-    }
-    _cs = 1;
-    _spi.write(0xFF);
-    return -1; // timeout
-}
-
-int SDFileSystem::_read(char *buffer, int length) {
-    _cs = 0;
-
-    // read until start byte (0xFF)
-    while(_spi.write(0xFF) != 0xFE);
-
-    // read data
-    for(int i=0; i<length; i++) {
-        buffer[i] = _spi.write(0xFF);
-    }
-    _spi.write(0xFF); // checksum
-    _spi.write(0xFF);
-
-    _cs = 1;    
-    _spi.write(0xFF);
-    return 0;
-}
-
-int SDFileSystem::_write(const char *buffer, int length) {
-    _cs = 0;
-    
-    // indicate start of block
-    _spi.write(0xFE);
-    
-    // write the data
-    for(int i=0; i<length; i++) {
-        _spi.write(buffer[i]);
-    }
-    
-    // write the checksum
-    _spi.write(0xFF); 
-    _spi.write(0xFF);
-
-    // check the repsonse token
-    if((_spi.write(0xFF) & 0x1F) != 0x05) {
-        _cs = 1;
-        _spi.write(0xFF);        
-        return 1;
-    }
-
-    // wait for write to finish
-    while(_spi.write(0xFF) == 0);
-
-    _cs = 1; 
-    _spi.write(0xFF);
-    return 0;
-}
-
-static int ext_bits(char *data, int msb, int lsb) {
-    int bits = 0;
-    int size = 1 + msb - lsb; 
-    for(int i=0; i<size; i++) {
-        int position = lsb + i;
-        int byte = 15 - (position >> 3);
-        int bit = position & 0x7;
-        int value = (data[byte] >> bit) & 1;
-        bits |= value << i;
-    }
-    return bits;
-}
-
-int SDFileSystem::_sd_sectors() {
-
-    // CMD9, Response R2 (R1 byte + 16-byte block read)
-    if(_cmdx(9, 0) != 0) {
-        fprintf(stderr, "Didn't get a response from the disk\n");
-        return 0;
-    }
-    
-    char csd[16];    
-    if(_read(csd, 16) != 0) {
-        fprintf(stderr, "Couldn't read csd response from disk\n");
-        return 0;
-    }
-
-    // csd_structure : csd[127:126]
-    // c_size        : csd[73:62]
-    // c_size_mult   : csd[49:47]
-    // read_bl_len   : csd[83:80] - the *maximum* read block length
-
-    int csd_structure = ext_bits(csd, 127, 126);
-    int c_size = ext_bits(csd, 73, 62);
-    int c_size_mult = ext_bits(csd, 49, 47);
-    int read_bl_len = ext_bits(csd, 83, 80);
-
-//    printf("CSD_STRUCT = %d\n", csd_structure);
-    
-    if(csd_structure != 0) {
-        fprintf(stderr, "This disk tastes funny! I only know about type 0 CSD structures\n");
-        return 0;
-    }
-             
-    // memory capacity = BLOCKNR * BLOCK_LEN
-    // where
-    //  BLOCKNR = (C_SIZE+1) * MULT
-    //  MULT = 2^(C_SIZE_MULT+2) (C_SIZE_MULT < 8)
-    //  BLOCK_LEN = 2^READ_BL_LEN, (READ_BL_LEN < 12)         
-                            
-    int block_len = 1 << read_bl_len;
-    int mult = 1 << (c_size_mult + 2);
-    int blocknr = (c_size + 1) * mult;
-    int capacity = blocknr * block_len;
-        
-    int blocks = capacity / 512;
-        
-    return blocks;
-}
--- a/SDFileSystem/SDFileSystem.h	Mon Dec 19 16:13:32 2011 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,81 +0,0 @@
-/* mbed SDFileSystem Library, for providing file access to SD cards
- * Copyright (c) 2008-2010, sford
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
-#ifndef MBED_SDFILESYSTEM_H
-#define MBED_SDFILESYSTEM_H
-
-#include "mbed.h"
-#include "FATFileSystem.h"
-
-/** Access the filesystem on an SD Card using SPI
- *
- * @code
- * #include "mbed.h"
- * #include "SDFileSystem.h"
- *
- * SDFileSystem sd(p5, p6, p7, p12, "sd"); // mosi, miso, sclk, cs
- *  
- * int main() {
- *     FILE *fp = fopen("/sd/myfile.txt", "w");
- *     fprintf(fp, "Hello World!\n");
- *     fclose(fp);
- * }
- */
-class SDFileSystem : public FATFileSystem {
-public:
-
-    /** Create the File System for accessing an SD Card using SPI
-     *
-     * @param mosi SPI mosi pin connected to SD Card
-     * @param miso SPI miso pin conencted to SD Card
-     * @param sclk SPI sclk pin connected to SD Card
-     * @param cs   DigitalOut pin used as SD Card chip select
-     * @param name The name used to access the virtual filesystem
-     */
-    SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name);
-    virtual int disk_initialize();
-    virtual int disk_write(const char *buffer, int block_number);
-    virtual int disk_read(char *buffer, int block_number);    
-    virtual int disk_status();
-    virtual int disk_sync();
-    virtual int disk_sectors();
-
-protected:
-
-    int _cmd(int cmd, int arg);
-    int _cmdx(int cmd, int arg);
-    int _cmd8();
-    int _cmd58();
-    int initialise_card();
-    int initialise_card_v1();
-    int initialise_card_v2();
-    
-    int _read(char *buffer, int length);
-    int _write(const char *buffer, int length);
-    int _sd_sectors();
-    int _sectors;
-    
-    SPI _spi;
-    DigitalOut _cs;     
-};
-
-#endif
--- a/USBDevice/USBAudio/USBAudio.cpp	Mon Dec 19 16:13:32 2011 +0000
+++ b/USBDevice/USBAudio/USBAudio.cpp	Tue Dec 20 10:44:10 2011 +0000
@@ -36,7 +36,7 @@
     channel_config = (channel_nb == 1) ? CHANNEL_M : CHANNEL_L + CHANNEL_R;
 
     SOF_handler = false;
-    readIN = false;
+    writeIN = false;
     interruptIN = false;
 
     buf_stream = NULL;
@@ -46,25 +46,26 @@
 }
 
 bool USBAudio::write(uint8_t * buf) {
-    readIN = false;
+    writeIN = false;
     SOF_handler = false;
     if (interruptIN) {
-        USBDevice::writeNB(EP3IN, buf, 16, 16);
+        USBDevice::writeNB(EP3IN, buf, PACKET_SIZE_ISO, PACKET_SIZE_ISO);
     } else {
         buf_stream = buf;
     }
     while (!SOF_handler);
     if (interruptIN) {
-        while (!readIN);
+        while (!writeIN);
     }
     buf_stream = NULL;
     return true;
 }
 
+DigitalOut p1(p18);
 // Called in ISR context on each start of frame
 void USBAudio::SOF(int frameNumber) {
     if (buf_stream != NULL) {
-        USBDevice::writeNB(EP3IN, (uint8_t *)buf_stream, 16, 16);
+        USBDevice::writeNB(EP3IN, (uint8_t *)buf_stream, PACKET_SIZE_ISO, PACKET_SIZE_ISO);
     }
     SOF_handler = true;
 }
@@ -72,7 +73,7 @@
 
 bool USBAudio::EP3_IN_callback() {
     interruptIN = true;
-    readIN = true;
+    writeIN = true;
     return true;
 }
 
@@ -98,91 +99,86 @@
     }
     if (interface == 1 && (alternate == 0 || alternate == 1)) {
         return true;
-    } else
-        printf("intf: %d, alt: %d\r\n", interface, alternate);
+    }
     return false;
 }
 
 
 
 #define TOTAL_DESCRIPTOR_LENGTH ((1 * CONFIGURATION_DESCRIPTOR_LENGTH) \
-                               + (5 * INTERFACE_DESCRIPTOR_LENGTH) \
+                               + (3 * INTERFACE_DESCRIPTOR_LENGTH) \
                                + (1 * CONTROL_INTERFACE_DESCRIPTOR_LENGTH) \
-                               + (2 * INPUT_TERMINAL_DESCRIPTOR_LENGTH) \
-                               + (2 * FEATURE_UNIT_DESCRIPTOR_LENGTH) \
-                               + (2 * OUTPUT_TERMINAL_DESCRIPTOR_LENGTH) \
-                               + (0x07) \
-                               + (2 * STREAMING_INTERFACE_DESCRIPTOR_LENGTH) \
-                               + (2 * FORMAT_TYPE_I_DESCRIPTOR_LENGTH) \
-                               + (2 * (ENDPOINT_DESCRIPTOR_LENGTH + 2)) \
-                               + (2 * STREAMING_ENDPOINT_DESCRIPTOR_LENGTH) )
+                               + (1 * INPUT_TERMINAL_DESCRIPTOR_LENGTH) \
+                               + (1 * OUTPUT_TERMINAL_DESCRIPTOR_LENGTH) \
+                               + (1 * STREAMING_INTERFACE_DESCRIPTOR_LENGTH) \
+                               + (1 * FORMAT_TYPE_I_DESCRIPTOR_LENGTH) \
+                               + (1 * (ENDPOINT_DESCRIPTOR_LENGTH + 2)) \
+                               + (1 * STREAMING_ENDPOINT_DESCRIPTOR_LENGTH) )
 
 #define TOTAL_CONTROL_INTF_LENGTH    (CONTROL_INTERFACE_DESCRIPTOR_LENGTH + \
-                                      2 * INPUT_TERMINAL_DESCRIPTOR_LENGTH     + \
-                                      2 * FEATURE_UNIT_DESCRIPTOR_LENGTH    + \
-                                      2 * OUTPUT_TERMINAL_DESCRIPTOR_LENGTH + \
-                                      0x07)
+                                      1 * INPUT_TERMINAL_DESCRIPTOR_LENGTH     + \
+                                      1 * OUTPUT_TERMINAL_DESCRIPTOR_LENGTH)
 
 uint8_t * USBAudio::configurationDesc() {
     static uint8_t configDescriptor[] = {
         // Configuration 1
-        CONFIGURATION_DESCRIPTOR_LENGTH,    // bLength
-        CONFIGURATION_DESCRIPTOR,           // bDescriptorType
-        0x64,   // wTotalLength (LSB)
-        0x00,   // wTotalLength (MSB)
-        0x02,   // bNumInterfaces
-        DEFAULT_CONFIGURATION,  // bConfigurationValue
-        0x00,   // iConfiguration
-        0x80,   // bmAttributes
-        50,     // bMaxPower
+        CONFIGURATION_DESCRIPTOR_LENGTH,        // bLength
+        CONFIGURATION_DESCRIPTOR,               // bDescriptorType
+        LSB(TOTAL_DESCRIPTOR_LENGTH),           // wTotalLength (LSB)
+        MSB(TOTAL_DESCRIPTOR_LENGTH),           // wTotalLength (MSB)
+        0x02,                                   // bNumInterfaces
+        DEFAULT_CONFIGURATION,                  // bConfigurationValue
+        0x00,                                   // iConfiguration
+        0x80,                                   // bmAttributes
+        50,                                     // bMaxPower
 
         // Interface 0, Alternate Setting 0, Audio Control
-        INTERFACE_DESCRIPTOR_LENGTH,    // bLength
-        INTERFACE_DESCRIPTOR,           // bDescriptorType
-        0x00,   // bInterfaceNumber
-        0x00,   // bAlternateSetting
-        0x00,   // bNumEndpoints
-        0x01,   // bInterfaceClass
-        0x01,   // bInterfaceSubClass
-        0x00,   // bInterfaceProtocol
-        0x00,   // iInterface
+        INTERFACE_DESCRIPTOR_LENGTH,            // bLength
+        INTERFACE_DESCRIPTOR,                   // bDescriptorType
+        0x00,                                   // bInterfaceNumber
+        0x00,                                   // bAlternateSetting
+        0x00,                                   // bNumEndpoints
+        AUDIO_CLASS,                            // bInterfaceClass
+        SUBCLASS_AUDIOCONTROL,                  // bInterfaceSubClass
+        0x00,                                   // bInterfaceProtocol
+        0x00,                                   // iInterface
 
 
         // Audio Control Interface
-        0x09,   // bLength
-        0x24,   // bDescriptorType
-        0x01,   // bDescriptorSubtype
-        LSB(0x0100),    // bcdADC (LSB)
-        MSB(0x0100),    // bcdADC (MSB)
-        0x1e,   // wTotalLength
-        0x00,   // wTotalLength
-        0x01,   // bInCollection
-        0x01,   // baInterfaceNr
+        CONTROL_INTERFACE_DESCRIPTOR_LENGTH,    // bLength
+        INTERFACE_DESCRIPTOR_TYPE,              // bDescriptorType
+        CONTROL_HEADER,                         // bDescriptorSubtype
+        LSB(0x0100),                            // bcdADC (LSB)
+        MSB(0x0100),                            // bcdADC (MSB)
+        LSB(TOTAL_CONTROL_INTF_LENGTH),         // wTotalLength
+        MSB(TOTAL_CONTROL_INTF_LENGTH),         // wTotalLength
+        0x01,                                   // bInCollection
+        0x01,                                   // baInterfaceNr
 
-        // Audio Input Terminal (Speaker)
-        0x0c,   // bLength
-        0x24,   // bDescriptorType
-        0x02,   // bDescriptorSubtype
-        0x01,   // bTerminalID
-        0x01,   // wTerminalType
-        0x02,   // wTerminalType
-        0x00,   // bAssocTerminal
-        0x01,   // bNrChannels
-        0x00,   // wChannelConfig
-        0x00,   // wChannelConfig
-        0x00,   // iChannelNames
-        0x00,   // iTerminal
+        // Audio Input Terminal (Microphone)
+        INPUT_TERMINAL_DESCRIPTOR_LENGTH,       // bLength
+        INTERFACE_DESCRIPTOR_TYPE,              // bDescriptorType
+        CONTROL_INPUT_TERMINAL,                 // bDescriptorSubtype
+        0x01,                                   // bTerminalID
+        LSB(TERMINAL_MICROPHONE),               // wTerminalType
+        MSB(TERMINAL_MICROPHONE),               // wTerminalType
+        0x00,                                   // bAssocTerminal
+        channel_nb,                             // bNrChannels
+        LSB(channel_config),                    // wChannelConfig
+        MSB(channel_config),                    // wChannelConfig
+        0x00,                                   // iChannelNames
+        0x00,                                   // iTerminal
 
         // Audio Output Terminal (Speaker)
-        0x09,   // bLength
-        0x24,   // bDescriptorType
-        0x03,   // bDescriptorSubtype
-        0x02,   // bTerminalID
-        0x01,   // wTerminalType
-        0x01,   // wTerminalType
-        0x00,   // bAssocTerminal
-        0x01,   // bSourceID
-        0x00,   // iTerminal
+        OUTPUT_TERMINAL_DESCRIPTOR_LENGTH,      // bLength
+        INTERFACE_DESCRIPTOR_TYPE,              // bDescriptorType
+        CONTROL_OUTPUT_TERMINAL,                // bDescriptorSubtype
+        0x02,                                   // bTerminalID
+        LSB(TERMINAL_USB_STREAMING),            // wTerminalType
+        MSB(TERMINAL_USB_STREAMING),            // wTerminalType
+        0x00,                                   // bAssocTerminal
+        0x01,                                   // bSourceID
+        0x00,                                   // iTerminal
 
 
 
@@ -192,76 +188,73 @@
 
 
         // Interface 1, Alternate Setting 0, Audio Streaming - Zero Bandwith
-        0x09,   // bLength
-        0x04,   // bDescriptorType
-        0x01,   // bInterfaceNumber
-        0x00,   // bAlternateSetting
-        0x00,   // bNumEndpoints
-        0x01,   // bInterfaceClass
-        0x02,   // bInterfaceSubClass
-        0x00,   // bInterfaceProtocol
-        0x00,   // iInterface
+        INTERFACE_DESCRIPTOR_LENGTH,            // bLength
+        INTERFACE_DESCRIPTOR,                   // bDescriptorType
+        0x01,                                   // bInterfaceNumber
+        0x00,                                   // bAlternateSetting
+        0x00,                                   // bNumEndpoints
+        AUDIO_CLASS,                            // bInterfaceClass
+        SUBCLASS_AUDIOSTREAMING,                // bInterfaceSubClass
+        0x00,                                   // bInterfaceProtocol
+        0x00,                                   // iInterface
 
         // Interface 1, Alternate Setting 1, Audio Streaming - Operational
-        0x09,   // bLength
-        0x04,   // bDescriptorType
-        0x01,   // bInterfaceNumber
-        0x01,   // bAlternateSetting
-        0x01,   // bNumEndpoints
-        0x01,   // bInterfaceClass
-        0x02,   // bInterfaceSubClass
-        0x00,   // bInterfaceProtocol
-        0x00,   // iInterface
+        INTERFACE_DESCRIPTOR_LENGTH,            // bLength
+        INTERFACE_DESCRIPTOR,                   // bDescriptorType
+        0x01,                                   // bInterfaceNumber
+        0x01,                                   // bAlternateSetting
+        0x01,                                   // bNumEndpoints
+        AUDIO_CLASS,                            // bInterfaceClass
+        SUBCLASS_AUDIOSTREAMING,                // bInterfaceSubClass
+        0x00,                                   // bInterfaceProtocol
+        0x00,                                   // iInterface
 
         // Audio Streaming Interface
-        0x07,   // bLength
-        0x24,   // bDescriptorType
-        0x01,   // bDescriptorSubtype
-        0x02,   // bTerminalLink
-        0x01,   // bDelay
-        0x01,   // wFormatTag
-        0x00,   // wFormatTag
+        STREAMING_INTERFACE_DESCRIPTOR_LENGTH,  // bLength
+        INTERFACE_DESCRIPTOR_TYPE,              // bDescriptorType
+        SUBCLASS_AUDIOCONTROL,                  // bDescriptorSubtype
+        0x02,                                   // bTerminalLink (output terminal microphone)
+        0x01,                                   // bDelay
+        0x01,                                   // wFormatTag
+        0x00,                                   // wFormatTag
 
         // Audio Type I Format
-        0x0B,   // bLength
-        0x24,   // bDescriptorType
-        0x02,   // bDescriptorSubtype
-        0x01,   // bFormatType
-        0x01,   // bNrChannels
-        0x02,   // bSubFrameSize
-        0x10,   // bBitResolution
-        0x01,   // bSamFreqType
-        0x40,   // tSamFreq
-        0x1F,   // tSamFreq
-        0x00,   // tSamFreq
+        FORMAT_TYPE_I_DESCRIPTOR_LENGTH,        // bLength
+        INTERFACE_DESCRIPTOR_TYPE,              // bDescriptorType
+        SUBCLASS_AUDIOSTREAMING,                // bDescriptorSubtype
+        FORMAT_TYPE_I,                          // bFormatType
+        channel_nb,                             // bNrChannels
+        0x02,                                   // bSubFrameSize
+        0x10,                                   // bBitResolution
+        0x01,                                   // bSamFreqType
+        LSB(FREQ),                              // tSamFreq
+        (FREQ >> 8) & 0xff,                     // tSamFreq
+        (FREQ >> 16) & 0xff,                    // tSamFreq
 
         // Endpoint - Standard Descriptor
-        0x09,   // bLength
-        0x05,   // bDescriptorType
-        PHY_TO_DESC(EPISO_IN),  // bEndpointAddress
-        E_ISOCHRONOUS,          // bmAttributes
-        LSB(PACKET_SIZE_ISO),   // wMaxPacketSize
-        MSB(PACKET_SIZE_ISO),   // wMaxPacketSize
-        0x01,   // bInterval
-        0x00,   // bRefresh
-        0x00,   // bSynchAddress
+        ENDPOINT_DESCRIPTOR_LENGTH + 2,         // bLength
+        ENDPOINT_DESCRIPTOR,                    // bDescriptorType
+        PHY_TO_DESC(EPISO_IN),                  // bEndpointAddress
+        E_ISOCHRONOUS,                          // bmAttributes
+        LSB(PACKET_SIZE_ISO),                   // wMaxPacketSize
+        MSB(PACKET_SIZE_ISO),                   // wMaxPacketSize
+        0x01,                                   // bInterval
+        0x00,                                   // bRefresh
+        0x00,                                   // bSynchAddress
 
         // Endpoint - Audio Streaming
-        0x07,   // bLength
-        0x25,   // bDescriptorType
-        0x01,   // bDescriptor
-        0x00,   // bmAttributes
-        0x00,   // bLockDelayUnits
-        LSB(0x0000),    // wLockDelay
-        MSB(0x0000),    // wLockDelay
-
-
+        STREAMING_ENDPOINT_DESCRIPTOR_LENGTH,   // bLength
+        ENDPOINT_DESCRIPTOR_TYPE,               // bDescriptorType
+        ENDPOINT_GENERAL,                       // bDescriptor
+        0x00,                                   // bmAttributes
+        0x00,                                   // bLockDelayUnits
+        LSB(0x0000),                            // wLockDelay
+        MSB(0x0000),                            // wLockDelay
 
 
         // Terminator
         0
     };
-    //printf("size config: %d\r\n", sizeof(configDescriptor));
     return configDescriptor;
 }
 
--- a/USBDevice/USBAudio/USBAudio.h	Mon Dec 19 16:13:32 2011 +0000
+++ b/USBDevice/USBAudio/USBAudio.h	Tue Dec 20 10:44:10 2011 +0000
@@ -182,8 +182,11 @@
     // boolean showing that the SOF handler has been called. Useful for readNB.
     volatile bool SOF_handler;
     
+    // Is there an interrupt
     volatile bool interruptIN;
-    volatile bool readIN;
+    
+    // write has been done
+    volatile bool writeIN;
 
 };
 
--- a/USBDevice/USBAudio/USBAudio_Types.h	Mon Dec 19 16:13:32 2011 +0000
+++ b/USBDevice/USBAudio/USBAudio_Types.h	Tue Dec 20 10:44:10 2011 +0000
@@ -22,19 +22,6 @@
 
 #define DEFAULT_CONFIGURATION (1)
 
-// Audio Request Codes
-#define REQUEST_SET_CUR     0x01
-#define REQUEST_GET_CUR     0x81
-#define REQUEST_SET_MIN     0x02
-#define REQUEST_GET_MIN     0x82
-#define REQUEST_SET_MAX     0x03
-#define REQUEST_GET_MAX     0x83
-#define REQUEST_SET_RES     0x04
-#define REQUEST_GET_RES     0x84
-
-#define MUTE_CONTROL        0x01
-#define VOLUME_CONTROL      0x02
-
 
 // Audio Descriptor Sizes
 #define CONTROL_INTERFACE_DESCRIPTOR_LENGTH       0x09
--- a/main.cpp	Mon Dec 19 16:13:32 2011 +0000
+++ b/main.cpp	Tue Dec 20 10:44:10 2011 +0000
@@ -1,28 +1,43 @@
 #include "mbed.h"
 #include "USBAudio.h"
 
-extern "C" void HardFault_Handler() {
-    error("Hard Fault!\n");
-}
+// frequency: 8 kHz
+#define FREQ 8000
+
+// 1 channel: mono
+#define NB_CHA 1
 
-USBAudio audio(8000, 1, 0x74ac, 0x8788);
+// length of an audio packet: each ms, we receive 48 * 16bits ->48 * 2 bytes. as there is one channel, the length will be 48 * 2 * 1
+#define AUDIO_LENGTH_PACKET (FREQ/500) * NB_CHA
+
+USBAudio audio(FREQ, NB_CHA, 0xaac0, 0xa734);
 AnalogIn mic(p20);
-DigitalOut p(p21);
+DigitalOut p(p19);
 
-int16_t buf[8];
-
+// length of buffer = AUDIO_LENGTH_PACKET/2 because we are handling int16 and not bytes.
+int16_t buf[AUDIO_LENGTH_PACKET/2];
 
 int main() {
+    double mic_mean = 0.0;
+    double mic_value;
+
+    // compute average value of the microphone. We can then center the audio signal sent to the computer
+    for (int j = 0; j < 1000; j++) {
+        mic_value = (mic.read_u16() >> 3);
+        mic_mean = (mic_mean*j + mic_value)/(j+1);
+    }
 
     while (1) {
-        p = 1;
-        for (int i = 0; i < 8; i++) {
-            buf[i] = (mic.read_u16() >> 3) - 4100;
-            if (i != 7) {
+
+        // read 8 micro samples
+        for (int i = 0; i < AUDIO_LENGTH_PACKET/2; i++) {
+            buf[i] = (mic.read_u16() >> 3) - mic_mean;
+            if (i != AUDIO_LENGTH_PACKET/2) {
                 wait_us(110);
             }
         }
-        p = 0;
+        // send
         audio.write((uint8_t *)buf);
+
     }
 }