目录
CubeMX生成的USB Audio Device只支持播放，基于这个工程，修改为USB录音设备，只需要修改一个文件。
CubeMX版本是4.21.0（STM32Cube V1.0），这个关系不大。
这里没有配置用于连接ADC的IIS和IIC接口，只用于demo，USB声卡最终输出的数据是在程序中指定的。后续可以用IIS和IIC接入ADC芯片，也可以使用STM32本身的AD模块。
USB部分配置如下图，选择Device Only，然后在MiddleWares中选择Audio Device Class。
时钟自己生成就行，必须使用外部晶振才可以，在Input frequency中填入实际晶振数值。
然后进入如下Configuration页面。
在这个页面，先点击USB_DEVICE Configuration，配置如下。
然后点击USB_FS，配置如下，没有贴出来的都是默认的。
点击菜单栏Project，选择Settings，配置如下。
最后点击如下按钮，生成工程。
修改如下文件，直接用https://download.csdn.net/download/weixin_39228381/12766725中的文件替换即可（文件审核中，目前是404，和用如下代码段内容一致），修改了USB设备描述符和数据传输配置。这里只做一些说明，具体修改内容在附件里。
/**
******************************************************************************
* @file usbd_audio.c
* @author MCD Application Team
* @version V2.4.2
* @date 11-December-2015
* @brief This file provides the Audio core functions.
*
* @verbatim
*
* ===================================================================
* AUDIO Class Description
* ===================================================================
* This driver manages the Audio Class 1.0 following the "USB Device Class Definition for
* Audio Devices V1.0 Mar 18, 98".
* This driver implements the following aspects of the specification:
* - Device descriptor management
* - Configuration descriptor management
* - Standard AC Interface Descriptor management
* - 1 Audio Streaming Interface (with single channel, PCM, Stereo mode)
* - 1 Audio Streaming Endpoint
* - 1 Audio Terminal Input (1 channel)
* - Audio Class-Specific AC Interfaces
* - Audio Class-Specific AS Interfaces
* - AudioControl Requests: only SET_CUR and GET_CUR requests are supported (for Mute)
* - Audio Feature Unit (limited to Mute control)
* - Audio Synchronization type: Asynchronous
* - Single fixed audio sampling rate (configurable in usbd_conf.h file)
* The current audio class version supports the following audio features:
* - Pulse Coded Modulation (PCM) format
* - sampling rate: 48KHz.
* - Bit resolution: 16
* - Number of channels: 2
* - No volume control
* - Mute/Unmute capability
* - Asynchronous Endpoints
*
* @note In HS mode and when the DMA is used, all variables and data structures
* dealing with the DMA during the transaction process should be 32-bit aligned.
*
*
* @endverbatim
*
******************************************************************************
* @attention
*
* <h2><center>© COPYRIGHT 2015 STMicroelectronics</center></h2>
*
* Licensed under MCD-ST Liberty SW License Agreement V2, (the "License");
* You may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.st.com/software_license_agreement_liberty_v2
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
******************************************************************************
*/
/* Includes ------------------------------------------------------------------*/
#include "usbd_audio.h"
#include "usbd_desc.h"
#include "usbd_ctlreq.h"
/** @addtogroup STM32_USB_DEVICE_LIBRARY
* @{
*/
/** @defgroup USBD_AUDIO
* @brief usbd core module
* @{
*/
/** @defgroup USBD_AUDIO_Private_TypesDefinitions
* @{
*/
/**
* @}
*/
/** @defgroup USBD_AUDIO_Private_Defines
* @{
*/
/**
* @}
*/
/** @defgroup USBD_AUDIO_Private_Macros
* @{
*/
#define AUDIO_SAMPLE_FREQ(frq) (uint8_t)(frq), (uint8_t)((frq >> 8)), (uint8_t)((frq >> 16))
#define AUDIO_PACKET_SZE(frq) (uint8_t)(((frq * 2 * 2)/1000) & 0xFF), \
(uint8_t)((((frq * 2 * 2)/1000) >> 8) & 0xFF)
/**
* @}
*/
/** @defgroup USBD_AUDIO_Private_FunctionPrototypes
* @{
*/
static uint8_t USBD_AUDIO_Init (USBD_HandleTypeDef *pdev,
uint8_t cfgidx);
static uint8_t USBD_AUDIO_DeInit (USBD_HandleTypeDef *pdev,
uint8_t cfgidx);
static uint8_t USBD_AUDIO_Setup (USBD_HandleTypeDef *pdev,
USBD_SetupReqTypedef *req);
static uint8_t *USBD_AUDIO_GetCfgDesc (uint16_t *length);
static uint8_t *USBD_AUDIO_GetDeviceQualifierDesc (uint16_t *length);
static uint8_t USBD_AUDIO_DataIn (USBD_HandleTypeDef *pdev, uint8_t epnum);
static uint8_t USBD_AUDIO_DataOut (USBD_HandleTypeDef *pdev, uint8_t epnum);
static uint8_t USBD_AUDIO_EP0_RxReady (USBD_HandleTypeDef *pdev);
static uint8_t USBD_AUDIO_EP0_TxReady (USBD_HandleTypeDef *pdev);
static uint8_t USBD_AUDIO_SOF (USBD_HandleTypeDef *pdev);
static uint8_t USBD_AUDIO_IsoINIncomplete (USBD_HandleTypeDef *pdev, uint8_t epnum);
static uint8_t USBD_AUDIO_IsoOutIncomplete (USBD_HandleTypeDef *pdev, uint8_t epnum);
static void AUDIO_REQ_GetCurrent(USBD_HandleTypeDef *pdev, USBD_SetupReqTypedef *req);
static void AUDIO_REQ_SetCurrent(USBD_HandleTypeDef *pdev, USBD_SetupReqTypedef *req);
/**
* @}
*/
/** @defgroup USBD_AUDIO_Private_Variables
* @{
*/
USBD_ClassTypeDef USBD_AUDIO =
{
USBD_AUDIO_Init,
USBD_AUDIO_DeInit,
USBD_AUDIO_Setup,
USBD_AUDIO_EP0_TxReady,
USBD_AUDIO_EP0_RxReady,
USBD_AUDIO_DataIn,
USBD_AUDIO_DataOut,
USBD_AUDIO_SOF,
USBD_AUDIO_IsoINIncomplete,
USBD_AUDIO_IsoOutIncomplete,
USBD_AUDIO_GetCfgDesc,
USBD_AUDIO_GetCfgDesc,
USBD_AUDIO_GetCfgDesc,
USBD_AUDIO_GetDeviceQualifierDesc,
};
/* 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 109 bytes*/
HIBYTE(USB_AUDIO_CONFIG_DESC_SIZ),
0x02, /* bNumInterfaces */
0x01, /* bConfigurationValue */
0x00, /* iConfiguration */
0x80, /* bmAttributes BUS Powred*/ // 0xC0 ---> 0x80
0x20, /* bMaxPower = 100 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 = 39*/ //²»Í¬111111111111111111111111
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 AUDIO_TERMINAL_USB_STREAMING 0x0101 */
0x02, // 0x01 ---> 0x02
0x00, /* bAssocTerminal */
0x01, /* bNrChannels */
0x00, /* wChannelConfig 0x0000 Mono */ //ÐèÒª¸Ä³Éstereo111111111111111111111111111
0x00,
0x00, /* iChannelNames */
0x00, /* iTerminal */
/* 12 byte*/
/* USB Speaker Audio Feature Unit Descriptor */
0x09, /* bLength */
AUDIO_INTERFACE_DESCRIPTOR_TYPE, /* bDescriptorType */
AUDIO_CONTROL_OUTPUT_TERMINAL, /* bDescriptorSubtype */ //6 ---> 3
AUDIO_OUT_STREAMING_CTRL, /* bUnitID */
0x01, /* bSourceID */
0x01, /* bControlSize */
0,// |AUDIO_CONTROL_VOLUME, /* bmaControls(0) */
1, /* bmaControls(1) */
0, /* iTerminal */
/* 09 byte*/
/*USB Speaker Output Terminal Descriptor */
0x09, /* bLength */
0x04, /* bDescriptorType */
0x01, /* bDescriptorSubtype */
0x00, /* bTerminalID */
0x00, /* wTerminalType 0x0301*/
0x01,
0x02, /* bAssocTerminal */
0x00, /* bSourceID */
0x00, /* iTerminal */
/* 09 byte*/
/* USB Speaker Standard AS Interface Descriptor - Audio Streaming Zero Bandwith */
/* Interface 1, Alternate Setting 0 */
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 Standard AS Interface Descriptor - Audio Streaming Operational */
/* Interface 1, Alternate Setting 1 */
7, /* bLength */
0x24, /* bDescriptorType */
0x01, /* bInterfaceNumber */
0x02, /* bAlternateSetting */
0x01, /* bNumEndpoints */
1, /* bInterfaceClass */
0, /* bInterfaceSubClass */
/* 07 byte*/
/* USB Speaker Audio Type III Format Interface Descriptor */
0x0B, /* bLength */
AUDIO_INTERFACE_DESCRIPTOR_TYPE, /* bDescriptorType */
AUDIO_STREAMING_FORMAT_TYPE, /* bDescriptorSubtype */
0x01, /* bFormatType */
0x01, /* bNrChannels */
0x02, /* bSubFrameSize : 2 Bytes per frame (16bits) */
0x10, /* 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 */
0x81, /* bEndpointAddress 1 out endpoint*/
USBD_EP_TYPE_ISOC, /* bmAttributes */
AUDIO_PACKET_SZE(USBD_AUDIO_FREQ), /* wMaxPacketSize in Bytes (Freq(Samples)*2(Stereo)*2(HalfWord)) */
0x01, /* 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 */
0x80, /* 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,
};
/**
* @}
*/
/** @defgroup USBD_AUDIO_Private_Functions
* @{
*/
/**
* @brief USBD_AUDIO_Init
* Initialize the AUDIO interface
* @param pdev: device instance
* @param cfgidx: Configuration index
* @retval status
*/
static uint8_t USBD_AUDIO_Init (USBD_HandleTypeDef *pdev,
uint8_t cfgidx)
{
USBD_AUDIO_HandleTypeDef *haudio;
USBD_LL_OpenEP(pdev,
0x81,
USBD_EP_TYPE_ISOC,
AUDIO_OUT_PACKET);
pdev->pClassData = USBD_malloc(sizeof (USBD_AUDIO_HandleTypeDef));
if(pdev->pClassData == NULL)
{
return USBD_FAIL;
}
else
{
haudio = (USBD_AUDIO_HandleTypeDef*) pdev->pClassData;
haudio->alt_setting = 0;
haudio->offset = AUDIO_OFFSET_UNKNOWN;
haudio->wr_ptr = 0;
haudio->rd_ptr = 0;
haudio->rd_enable = 0;
int16_t *ps = (int16_t*)haudio->buffer;
for(uint16_t i = 0; i < AUDIO_TOTAL_BUF_SIZE / 2; i ++)
{
ps[i] = i * 10;
}
/* Initialize the Audio output Hardware layer */
/*if (((USBD_AUDIO_ItfTypeDef *)pdev->pUserData)->Init(USBD_AUDIO_FREQ, AUDIO_DEFAULT_VOLUME, 0) != USBD_OK)
{
return USBD_FAIL;
}*/
/* Prepare Out endpoint to receive 1st packet */
/*USBD_LL_PrepareReceive(pdev,
0x81,
haudio->buffer,
AUDIO_OUT_PACKET);*/
HAL_StatusTypeDef hal_status = HAL_PCD_EP_Transmit(pdev->pData, 0x81, haudio->buffer, AUDIO_OUT_PACKET);
printf("HAL_PCD_EP_Transmit returns %d\n", hal_status);
}
return USBD_OK;
}
/**
* @brief USBD_AUDIO_Init
* DeInitialize the AUDIO layer
* @param pdev: device instance
* @param cfgidx: Configuration index
* @retval status
*/
static uint8_t USBD_AUDIO_DeInit (USBD_HandleTypeDef *pdev,
uint8_t cfgidx)
{
/* Open EP OUT */
USBD_LL_CloseEP(pdev, 0x81);
return USBD_OK;
}
/**
* @brief USBD_AUDIO_Setup
* Handle the AUDIO specific requests
* @param pdev: instance
* @param req: usb requests
* @retval status
*/
static uint8_t USBD_AUDIO_Setup (USBD_HandleTypeDef *pdev,
USBD_SetupReqTypedef *req)
{
USBD_AUDIO_HandleTypeDef *haudio;
uint16_t len;
uint8_t *pbuf;
uint8_t ret = USBD_OK;
haudio = (USBD_AUDIO_HandleTypeDef*) pdev->pClassData;
printf("%x\n", req->bmRequest & USB_REQ_TYPE_MASK);
switch (req->bmRequest & USB_REQ_TYPE_MASK)
{
case USB_REQ_TYPE_CLASS :
switch (req->bRequest)
{
case AUDIO_REQ_GET_CUR:
AUDIO_REQ_GetCurrent(pdev, req);
break;
case AUDIO_REQ_SET_CUR:
AUDIO_REQ_SetCurrent(pdev, req);
break;
default:
USBD_CtlError (pdev, req);
ret = USBD_FAIL;
}
break;
case USB_REQ_TYPE_STANDARD:
printf(" %x\n", req->bRequest);
switch (req->bRequest)
{
case USB_REQ_GET_DESCRIPTOR:
if( (req->wValue >> 8) == AUDIO_DESCRIPTOR_TYPE)
{
pbuf = USBD_AUDIO_CfgDesc + 18;
len = MIN(USB_AUDIO_DESC_SIZ , req->wLength);
USBD_CtlSendData (pdev,
pbuf,
len);
}
break;
case USB_REQ_GET_INTERFACE :
USBD_CtlSendData (pdev,
(uint8_t *)&(haudio->alt_setting),
1);
break;
case USB_REQ_SET_INTERFACE :
printf(" %d %d\n", req->wValue, USBD_MAX_NUM_INTERFACES);
if ((uint8_t)(req->wValue) <= USBD_MAX_NUM_INTERFACES)
{
haudio->alt_setting = (uint8_t)(req->wValue);
}
else
{
/* Call the error management function (command will be nacked */
USBD_CtlError (pdev, req);
}
break;
default:
USBD_CtlError (pdev, req);
ret = USBD_FAIL;
}
}
return ret;
}
/**
* @brief USBD_AUDIO_GetCfgDesc
* return configuration descriptor
* @param speed : current device speed
* @param length : pointer data length
* @retval pointer to descriptor buffer
*/
static uint8_t *USBD_AUDIO_GetCfgDesc (uint16_t *length)
{
*length = sizeof (USBD_AUDIO_CfgDesc);
return USBD_AUDIO_CfgDesc;
}
/**
* @brief USBD_AUDIO_DataIn
* handle data IN Stage
* @param pdev: device instance
* @param epnum: endpoint index
* @retval status
*/
static uint8_t USBD_AUDIO_DataIn (USBD_HandleTypeDef *pdev,
uint8_t epnum)
{
USBD_AUDIO_HandleTypeDef *haudio = (USBD_AUDIO_HandleTypeDef*) pdev->pClassData;
HAL_PCD_EP_Flush(pdev->pData, 0x81);
HAL_PCD_EP_Transmit(pdev->pData, 0x81, haudio->buffer, AUDIO_OUT_PACKET); //buffµÄ´óСÊÇAUDIO_OUT_PACKET * AUDIO_OUT_PACKET_NUM = (48000*2*2/1000) * 80
printf("UAIn %d %d %d %d\r\n", AUDIO_OUT_PACKET, ((int16_t*)haudio->buffer)[0], ((int16_t*)haudio->buffer)[1], ((int16_t*)haudio->buffer)[2]);
return USBD_OK;
}
/**
* @brief USBD_AUDIO_EP0_RxReady
* handle EP0 Rx Ready event
* @param pdev: device instance
* @retval status
*/
static uint8_t USBD_AUDIO_EP0_RxReady (USBD_HandleTypeDef *pdev)
{
/*USBD_AUDIO_HandleTypeDef *haudio;
haudio = (USBD_AUDIO_HandleTypeDef*) pdev->pClassData;
if (haudio->control.cmd == AUDIO_REQ_SET_CUR)
{// In this driver, to simplify code, only SET_CUR request is managed
if (haudio->control.unit == AUDIO_OUT_STREAMING_CTRL)
{
((USBD_AUDIO_ItfTypeDef *)pdev->pUserData)->MuteCtl(haudio->control.data[0]);
haudio->control.cmd = 0;
haudio->control.len = 0;
}
} */
return USBD_OK;
}
/**
* @brief USBD_AUDIO_EP0_TxReady
* handle EP0 TRx Ready event
* @param pdev: device instance
* @retval status
*/
static uint8_t USBD_AUDIO_EP0_TxReady (USBD_HandleTypeDef *pdev)
{
/*USBD_AUDIO_HandleTypeDef *haudio = (USBD_AUDIO_HandleTypeDef*) pdev->pClassData;
printf("USBD_AUDIO_EP0_TxReady %x %x %x\r\n", haudio->control.cmd, haudio->control.len, haudio->control.unit);
haudio->control.len = 64;*/
return USBD_OK;
}
/**
* @brief USBD_AUDIO_SOF
* handle SOF event
* @param pdev: device instance
* @retval status
*/
static uint8_t USBD_AUDIO_SOF (USBD_HandleTypeDef *pdev)
{
return USBD_OK;
}
/**
* @brief USBD_AUDIO_SOF
* handle SOF event
* @param pdev: device instance
* @retval status
*/
void USBD_AUDIO_Sync (USBD_HandleTypeDef *pdev, AUDIO_OffsetTypeDef offset)
{
int8_t shift = 0;
USBD_AUDIO_HandleTypeDef *haudio;
haudio = (USBD_AUDIO_HandleTypeDef*) pdev->pClassData;
haudio->offset = offset;
if(haudio->rd_enable == 1)
{
haudio->rd_ptr += AUDIO_TOTAL_BUF_SIZE/2;
if (haudio->rd_ptr == AUDIO_TOTAL_BUF_SIZE)
{
/* roll back */
haudio->rd_ptr = 0;
}
}
if(haudio->rd_ptr > haudio->wr_ptr)
{
if((haudio->rd_ptr - haudio->wr_ptr) < AUDIO_OUT_PACKET)
{
shift = -4;
}
else if((haudio->rd_ptr - haudio->wr_ptr) > (AUDIO_TOTAL_BUF_SIZE - AUDIO_OUT_PACKET))
{
shift = 4;
}
}
else
{
if((haudio->wr_ptr - haudio->rd_ptr) < AUDIO_OUT_PACKET)
{
shift = 4;
}
else if((haudio->wr_ptr - haudio->rd_ptr) > (AUDIO_TOTAL_BUF_SIZE - AUDIO_OUT_PACKET))
{
shift = -4;
}
}
if(haudio->offset == AUDIO_OFFSET_FULL)
{
((USBD_AUDIO_ItfTypeDef *)pdev->pUserData)->AudioCmd(&haudio->buffer[0],
AUDIO_TOTAL_BUF_SIZE/2 - shift,
AUDIO_CMD_PLAY);
haudio->offset = AUDIO_OFFSET_NONE;
}
}
/**
* @brief USBD_AUDIO_IsoINIncomplete
* handle data ISO IN Incomplete event
* @param pdev: device instance
* @param epnum: endpoint index
* @retval status
*/
static uint8_t USBD_AUDIO_IsoINIncomplete (USBD_HandleTypeDef *pdev, uint8_t epnum)
{
return USBD_OK;
}
/**
* @brief USBD_AUDIO_IsoOutIncomplete
* handle data ISO OUT Incomplete event
* @param pdev: device instance
* @param epnum: endpoint index
* @retval status
*/
static uint8_t USBD_AUDIO_IsoOutIncomplete (USBD_HandleTypeDef *pdev, uint8_t epnum)
{
return USBD_OK;
}
/**
* @brief USBD_AUDIO_DataOut
* handle data OUT Stage
* @param pdev: device instance
* @param epnum: endpoint index
* @retval status
*/
static uint8_t USBD_AUDIO_DataOut (USBD_HandleTypeDef *pdev,
uint8_t epnum)
{
return USBD_OK;
}
/**
* @brief AUDIO_Req_GetCurrent
* Handles the GET_CUR Audio control request.
* @param pdev: instance
* @param req: setup class request
* @retval status
*/
static void AUDIO_REQ_GetCurrent(USBD_HandleTypeDef *pdev, USBD_SetupReqTypedef *req)
{
USBD_AUDIO_HandleTypeDef *haudio;
haudio = (USBD_AUDIO_HandleTypeDef*) pdev->pClassData;
memset(haudio->control.data, 0, 64);
/* Send the current mute state */
USBD_CtlSendData (pdev,
haudio->control.data,
req->wLength);
}
/**
* @brief AUDIO_Req_SetCurrent
* Handles the SET_CUR Audio control request.
* @param pdev: instance
* @param req: setup class request
* @retval status
*/
static void AUDIO_REQ_SetCurrent(USBD_HandleTypeDef *pdev, USBD_SetupReqTypedef *req)
{
USBD_AUDIO_HandleTypeDef *haudio;
haudio = (USBD_AUDIO_HandleTypeDef*) pdev->pClassData;
if (req->wLength)
{
/* Prepare the reception of the buffer over EP0 */
USBD_CtlPrepareRx (pdev,
haudio->control.data,
req->wLength);
haudio->control.cmd = AUDIO_REQ_SET_CUR; /* Set the request value */
haudio->control.len = req->wLength; /* Set the request data length */
haudio->control.unit = HIBYTE(req->wIndex); /* Set the request target unit */
}
}
/**
* @brief DeviceQualifierDescriptor
* return Device Qualifier descriptor
* @param length : pointer data length
* @retval pointer to descriptor buffer
*/
static uint8_t *USBD_AUDIO_GetDeviceQualifierDesc (uint16_t *length)
{
*length = sizeof (USBD_AUDIO_DeviceQualifierDesc);
return USBD_AUDIO_DeviceQualifierDesc;
}
/**
* @brief USBD_AUDIO_RegisterInterface
* @param fops: Audio interface callback
* @retval status
*/
uint8_t USBD_AUDIO_RegisterInterface (USBD_HandleTypeDef *pdev,
USBD_AUDIO_ItfTypeDef *fops)
{
if(fops != NULL)
{
pdev->pUserData= fops;
}
return 0;
}
/**
* @}
*/
/**
* @}
*/
/**
* @}
*/
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
这部分内容参考了别的项目，具体差异可在附件中查看，结构体名称是USBD_AUDIO_CfgDesc。
注意：每次修改后，最好都吧windows设备管理器中STM32 Audio的声卡驱动卸载，然后从新安装，否则很多配置无法生效。
修改USBD_AUDIO_Init，把PC到STM32的数据传输节点改为STM32到PC的数据传输节点，并在这个函数中吧buffer初始化为固定的数据（仅用于demo）。
修改USBD_AUDIO_DeInit，也是修改数据传输节点。
无需修改USBD_AUDIO_Setup，只是加了些日志。
无需修改USBD_AUDIO_GetCfgDesc。
修改USBD_AUDIO_DataIn，这里DataIn是指PC接收数据，需要调用HAL_PCD_EP_Flush和HAL_PCD_EP_Transmit两个函数，如果真的有数据才调用第二个函数，这里没有做判断是否有数据，只用于demo。
修改USBD_AUDIO_EP0_RxReady，这各函数是PC给STM32传数据时才有用，这里直接return就行。
修改USBD_AUDIO_EP0_TxReady，这个函数目前也是空的，可以不使用。
修改USBD_AUDIO_DataOut，这里DataOut是指PC输出数据，不改也没关系，为节省代码空间直接清空。
其余的函数都没有改动。
进入属性，修改级别为10左右（另一个项目的声卡不受级别的影响，目前没找到解决方案。另外本声卡在Linux&Android平台，不会有这个级别的影响，说明和Windows的驱动有关）。
录制到的数据符合预期，只是在STM32程序中的数据基础上做了一个增益，如果在Linux&Android平台录制，则和原始数据一致。这里原始数据就是0 10 20 30 40 ... 1910 0 10 20的循环，即一个三角波。
