dspico-usb-examples/examples/usb-microphone/arm7/source/usb_descriptors.cpp

#include "common.h"
#include "UsbStringDescriptor.h"
#include "tusb.h"
#include "usb_descriptors.h"

/* A combination of interfaces must have a unique product id, since PC will save device driver after the first plug.
 * Same VID/PID with different interface e.g MSC (first), then CDC (later) will possibly cause system error on PC.
 *
 * Auto ProductID layout's Bitmap:
 *   [MSB]     AUDIO | MIDI | HID | MSC | CDC          [LSB]
 */
#define _PID_MAP(itf, n)  ( (CFG_TUD_##itf) << (n) )
#define USB_PID           (0x5000 | _PID_MAP(CDC, 0) | _PID_MAP(MSC, 1) | _PID_MAP(HID, 2) | \
    _PID_MAP(MIDI, 3) | _PID_MAP(AUDIO, 4) | _PID_MAP(VENDOR, 5) )

const u8* tud_descriptor_device_cb(void)
{
    static const tusb_desc_device_t deviceDescriptor =
    {
        .bLength            = sizeof(tusb_desc_device_t),
        .bDescriptorType    = TUSB_DESC_DEVICE,
        .bcdUSB             = 0x0200,

        // Use Interface Association Descriptor (IAD) for Audio
        // As required by USB Specs IAD's subclass must be common class (2) and protocol must be IAD (1)
        .bDeviceClass       = TUSB_CLASS_MISC,
        .bDeviceSubClass    = MISC_SUBCLASS_COMMON,
        .bDeviceProtocol    = MISC_PROTOCOL_IAD,
        .bMaxPacketSize0    = CFG_TUD_ENDPOINT0_SIZE,

        .idVendor           = 0xCafe,
        .idProduct          = USB_PID,
        .bcdDevice          = 0x0100,

        .iManufacturer      = STRID_MANUFACTURER,
        .iProduct           = STRID_PRODUCT,
        .iSerialNumber      = STRID_SERIAL,

        .bNumConfigurations = 0x01
    };

    return (const u8*)&deviceDescriptor;
}

#define CONFIG_TOTAL_LEN    (TUD_CONFIG_DESC_LEN + TUD_AUDIO_MIC_ONE_CH_DESC_LEN)

const u8* tud_descriptor_configuration_cb(u8 index)
{
    (void)index;

    static const u8 configurationDescriptor[] =
    {
        // Config number, interface count, string index, total length, attribute, power in mA
        TUD_CONFIG_DESCRIPTOR(1, ITF_NUM_TOTAL, 0, CONFIG_TOTAL_LEN, 0x00, 100),

        TUD_AUDIO_MIC_ONE_CH_DESCRIPTOR(0, STRID_AUDIO_INTERFACE,
            CFG_TUD_AUDIO_FUNC_1_N_BYTES_PER_SAMPLE_TX, CFG_TUD_AUDIO_FUNC_1_N_BYTES_PER_SAMPLE_TX * 8,
            EPNUM_AUDIO_IN, CFG_TUD_AUDIO_EP_SZ_IN)
    };

    return configurationDescriptor;
}

const u16* tud_descriptor_string_cb(u8 index, u16 langid)
{
    switch (index)
    {
        case STRID_LANGID:
        {
            static const UsbStringDescriptor<2> descriptor(0x0409);
            return (const u16*)&descriptor;
        }
        case STRID_MANUFACTURER:
        {
            return USB_STRING_DESCRIPTOR(u"LNH");
        }
        case STRID_PRODUCT:
        {
            return USB_STRING_DESCRIPTOR(u"DSpico Microphone Example");
        }
        case STRID_SERIAL:
        {
            return USB_STRING_DESCRIPTOR(u"123456789");
        }
        case STRID_AUDIO_INTERFACE:
        {
            return USB_STRING_DESCRIPTOR(u"DSpico Microphone");
        }
        default:
        {
            return nullptr;
        }
    }
}