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STM32 USBD MIC AND STREAMING AUDIO

bacnk
Associate II

I am configuring USBD to turn the STM32F4 Discovery into a headphone, meaning it can play music through USB and transmit data from the PDM microphone to the computer. I have completed the music playback part, but I am now working on the recording part and don't know how to configure USBD audio. Can you help me? 

#ifndef USE_USBD_COMPOSITE
/* USB AUDIO device Configuration Descriptor */
__ALIGN_BEGIN static uint8_t USBD_AUDIO_CfgDesc[USB_AUDIO_CONFIG_DESC_SIZ] __ALIGN_END =
{
/* Configuration 1 */
0x09, /* bLength */
USB_DESC_TYPE_CONFIGURATION, /* bDescriptorType */
LOBYTE(USB_AUDIO_CONFIG_DESC_SIZ), /* wTotalLength */
HIBYTE(USB_AUDIO_CONFIG_DESC_SIZ),
0x02, /* bNumInterfaces */
0x01, /* bConfigurationValue */
0x00, /* iConfiguration */
#if (USBD_SELF_POWERED == 1U)
0xC0, /* bmAttributes: Bus Powered according to user configuration */
#else
0x80, /* bmAttributes: Bus Powered according to user configuration */
#endif /* USBD_SELF_POWERED */
USBD_MAX_POWER, /* MaxPower (mA) */
/* 09 byte*/

/* USB Speaker Standard interface descriptor */
AUDIO_INTERFACE_DESC_SIZE, /* bLength */
USB_DESC_TYPE_INTERFACE, /* bDescriptorType */
0x00, /* bInterfaceNumber */
0x00, /* bAlternateSetting */
0x00, /* bNumEndpoints */
USB_DEVICE_CLASS_AUDIO, /* bInterfaceClass */
AUDIO_SUBCLASS_AUDIOCONTROL, /* bInterfaceSubClass */
AUDIO_PROTOCOL_UNDEFINED, /* bInterfaceProtocol */
0x00, /* iInterface */
/* 09 byte*/

/* USB Speaker Class-specific AC Interface Descriptor */
AUDIO_INTERFACE_DESC_SIZE, /* bLength */
AUDIO_INTERFACE_DESCRIPTOR_TYPE, /* bDescriptorType */
AUDIO_CONTROL_HEADER, /* bDescriptorSubtype */
0x00, /* 1.00 */ /* bcdADC */
0x01,
0x27, /* wTotalLength */
0x00,
0x01, /* bInCollection */
0x01, /* baInterfaceNr */
/* 09 byte*/

/* USB Speaker Input Terminal Descriptor */
AUDIO_INPUT_TERMINAL_DESC_SIZE, /* bLength */
AUDIO_INTERFACE_DESCRIPTOR_TYPE, /* bDescriptorType */
AUDIO_CONTROL_INPUT_TERMINAL, /* bDescriptorSubtype */
0x01, /* bTerminalID */
0x01, /* wTerminalType speaker 0x0201 */
0x02,
0x00, /* bAssocTerminal */
0x01, /* bNrChannels */
0x00, /* wChannelConfig 0x0000 Mono */
0x00,
0x00, /* iChannelNames */
0x00, /* iTerminal */
/* 12 byte*/

/* USB Speaker Audio Feature Unit Descriptor */
0x09, /* bLength */
AUDIO_INTERFACE_DESCRIPTOR_TYPE, /* bDescriptorType */
AUDIO_CONTROL_FEATURE_UNIT, /* bDescriptorSubtype */
AUDIO_OUT_STREAMING_CTRL, /* bUnitID */
0x01, /* bSourceID */
0x01, /* bControlSize */
AUDIO_CONTROL_MUTE, /* bmaControls(0) */
0, /* bmaControls(1) */
0x00, /* iTerminal */
/* 09 byte */

/* USB Speaker Output Terminal Descriptor */
0x09, /* bLength */
AUDIO_INTERFACE_DESCRIPTOR_TYPE, /* bDescriptorType */
AUDIO_CONTROL_OUTPUT_TERMINAL, /* bDescriptorSubtype */
0x03, /* bTerminalID */
0x01, /* wTerminalType 0x0101  stream audio*/
0x031,
0x00, /* bAssocTerminal */
0x02, /* bSourceID */
0x00, /* iTerminal */
/* 09 byte */

/* USB Speaker Standard AS Interface Descriptor - Audio Streaming Zero Bandwidth */
/* Interface 1, Alternate Setting 0 */
AUDIO_INTERFACE_DESC_SIZE, /* bLength */
USB_DESC_TYPE_INTERFACE, /* bDescriptorType */
0x01, /* bInterfaceNumber */
0x00, /* bAlternateSetting */
0x00, /* bNumEndpoints */
USB_DEVICE_CLASS_AUDIO, /* bInterfaceClass */
AUDIO_SUBCLASS_AUDIOSTREAMING, /* bInterfaceSubClass */
AUDIO_PROTOCOL_UNDEFINED, /* bInterfaceProtocol */
0x00, /* iInterface */
/* 09 byte*/

/* USB Speaker Standard AS Interface Descriptor - Audio Streaming Operational */
/* Interface 1, Alternate Setting 1 */
AUDIO_INTERFACE_DESC_SIZE, /* bLength */
USB_DESC_TYPE_INTERFACE, /* bDescriptorType */
0x01, /* bInterfaceNumber */
0x01, /* bAlternateSetting */
0x01, /* bNumEndpoints */
USB_DEVICE_CLASS_AUDIO, /* bInterfaceClass */
AUDIO_SUBCLASS_AUDIOSTREAMING, /* bInterfaceSubClass */
AUDIO_PROTOCOL_UNDEFINED, /* bInterfaceProtocol */
0x00, /* iInterface */
/* 09 byte*/

/* USB Speaker Audio Streaming Interface Descriptor */
AUDIO_STREAMING_INTERFACE_DESC_SIZE, /* bLength */
AUDIO_INTERFACE_DESCRIPTOR_TYPE, /* bDescriptorType */
AUDIO_STREAMING_GENERAL, /* bDescriptorSubtype */
0x01, /* bTerminalLink */
0x01, /* bDelay */
0x01, /* wFormatTag AUDIO_FORMAT_PCM 0x0001 */
0x00,
/* 07 byte*/

/* USB Speaker Audio Type III Format Interface Descriptor */
0x0B, /* bLength */
AUDIO_INTERFACE_DESCRIPTOR_TYPE, /* bDescriptorType */
AUDIO_STREAMING_FORMAT_TYPE, /* bDescriptorSubtype */
AUDIO_FORMAT_TYPE_I, /* bFormatType */
0x02, /* bNrChannels */
0x02, /* bSubFrameSize : 2 Bytes per frame (16bits) */
16, /* bBitResolution (16-bits per sample) */
0x01, /* bSamFreqType only one frequency supported */
AUDIO_SAMPLE_FREQ(USBD_AUDIO_FREQ), /* Audio sampling frequency coded on 3 bytes */
/* 11 byte*/

/* Endpoint 1 - Standard Descriptor */
AUDIO_STANDARD_ENDPOINT_DESC_SIZE, /* bLength */
USB_DESC_TYPE_ENDPOINT, /* bDescriptorType */
AUDIO_OUT_EP, /* bEndpointAddress 1 out endpoint */
USBD_EP_TYPE_ISOC, /* bmAttributes */
AUDIO_PACKET_SZE(USBD_AUDIO_FREQ), /* wMaxPacketSize in Bytes (Freq(Samples)*2(Stereo)*2(HalfWord)) */
AUDIO_FS_BINTERVAL, /* bInterval */
0x00, /* bRefresh */
0x00, /* bSynchAddress */
/* 09 byte*/

/* Endpoint - Audio Streaming Descriptor */
AUDIO_STREAMING_ENDPOINT_DESC_SIZE, /* bLength */
AUDIO_ENDPOINT_DESCRIPTOR_TYPE, /* bDescriptorType */
AUDIO_ENDPOINT_GENERAL, /* bDescriptor */
0x00, /* bmAttributes */
0x00, /* bLockDelayUnits */
0x00, /* wLockDelay */
0x00,
/* 07 byte*/
} ;

/* USB Standard Device Descriptor */
__ALIGN_BEGIN static uint8_t USBD_AUDIO_DeviceQualifierDesc[USB_LEN_DEV_QUALIFIER_DESC] __ALIGN_END =
{
USB_LEN_DEV_QUALIFIER_DESC,
USB_DESC_TYPE_DEVICE_QUALIFIER,
0x00,
0x02,
0x00,
0x00,
0x00,
0x40,
0x01,
0x00,
};  it's i my config

2 REPLIES 2
FBL
ST Employee

Hi @bacnk 

Did you check the example provided 

STM32Cube\Repository\STM32Cube_FW_F4_V1.28.0\Projects\STM324xG_EVAL\Applications\USB_Device\AUDIO_Standalone.

This application shows how to use the implementation of the audio streaming (Out: Speaker/Headset) capability on the STM32F407. Unfortunately, no examples provided cover the USB Microphone. You can use this MIC MP34DT01TR mounted on eval board and connected to (I2S) peripheral.

To give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.

bacnk
Associate II

what do you mean? headset has microphone and speaker right. or are you saying that the stm32f4 discovery cannot be used as a headset