代码收藏家 STM32-FS-USB-Device驱动代码简述（二）
目录
链接快速定位
前沿
1 STM32-FS-USB驱动程序下载
2 STM32-USB-FS设备固件库
2.1 USB应用程序层次结构
2.2 USB-FS_Device peripheral interface
2.3 USB-FS-Device_Driver medium layer
2.3 Application interface
3 代码讲解
3.1 初始化代码讲解
3.2 描述符讲解
3.3 中断处理函数
3.3.1 复位函数
3.3.2 正确传输完成函数
3.3.2.1 枚举过程正确传输完成函数
3.3.2.2 非端点0正确传输完成函数
链接快速定位
USB — 初识USB协议（一）
STM32F10x, STM32L1xx and STM32F3xx USB full speed device library (UM0424)
STM32 USB-FS-Device development kit
前沿
本小节主要讲述STM32F103USB设备模式下的标准库驱动程序结构，代码比较复杂，需要读者对USB协议有一个全面的了解，这里只讲述一下比较浅显的东西。
更多资料请参考：STM32 USB-FS-Device development kit
1 STM32-FS-USB驱动程序下载
每个芯片厂商都会提供一套属于自己的外设驱动及应用程序，这也是我们所说的生态的一部分，可以在官网下载。我们这里主要讲解STM32F103的USB驱动，所以我们需要去ST的官网下载我们需要的驱动程序，STM32F10x, STM32L1xx and STM32F3xx USB full speed device library (UM0424)。
2 STM32-USB-FS设备固件库
2.1 USB应用程序层次结构
下图显示了典型USB的不同组件之间的交互应用程序和USB FS设备库。
从上图可知，USB设备固件库被分为两层：
下图显示了USB FS设备库的程序包组织以及所有演示和子文件夹。
2.2 USB-FS_Device peripheral interface
USB全速设备外设接口层主要由以下部分组成：
2.3 USB-FS-Device_Driver medium layer
USB全速设备驱动中间层主要由以下部分组成：
2.3 Application interface
应用接口主要由以下部分组成：
3 代码讲解
代码讲解主要涉及以下几个方面：
这里以“VirtualComport_Loopback”工程为例进行讲解。
3.1 初始化代码讲解
GPIO初始化程序主要是初始化通信所使用的DM和DP引脚以及USB全速设备的DP上拉引脚。
void Set_System(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
/********************************************/
/* Configure USB DM/DP pins */
/********************************************/
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11 | GPIO_Pin_12;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_Init(GPIOA, &GPIO_InitStructure);
/* USB_DISCONNECT used as USB pull-up */
GPIO_InitStructure.GPIO_Pin = USB_DISCONNECT_PIN;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD;
GPIO_Init(USB_DISCONNECT, &GPIO_InitStructure);
/* Enable the USB disconnect GPIO clock */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIO_DISCONNECT, ENABLE);
}USB时钟配置主要是配置USB的PHY时钟，运行在48MHz的时钟下（系统时钟72M），并使能USB时钟。
void Set_USBClock(void)
{
/* Select USBCLK source */
RCC_USBCLKConfig(RCC_USBCLKSource_PLLCLK_1Div5);
/* Enable the USB clock */
RCC_APB1PeriphClockCmd(RCC_APB1Periph_USB, ENABLE);
}
USB中断初始化，主要是使能USB的中断，并且使能中断屏蔽位。
void USB_Interrupts_Config(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
/* 2 bit for pre-emption priority, 2 bits for subpriority */
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
/* Enable the USB interrupt */
NVIC_InitStructure.NVIC_IRQChannel = USB_LP_CAN1_RX0_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
/* Enable the USB Wake-up interrupt */
NVIC_InitStructure.NVIC_IRQChannel = USBWakeUp_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
NVIC_Init(&NVIC_InitStructure);
}RESULT PowerOn(void)
{
uint16_t wRegVal;
#if !defined (USE_NUCLEO)
/*** cable plugged-in ? ***/
USB_Cable_Config(ENABLE);
#endif
/*** CNTR_PWDN = 0 ***/
wRegVal = CNTR_FRES;
_SetCNTR(wRegVal);
/* The following sequence is recommended:
1- FRES = 0
2- Wait until RESET flag = 1 (polling)
3- clear ISTR register */
/*** CNTR_FRES = 0 ***/
wInterrupt_Mask = 0;
_SetCNTR(wInterrupt_Mask);
/* Wait until RESET flag = 1 (polling) */
while((_GetISTR()&ISTR_RESET) == 1);
/*** Clear pending interrupts ***/
SetISTR(0);
/*** Set interrupt mask ***/
wInterrupt_Mask = CNTR_RESETM | CNTR_SUSPM | CNTR_WKUPM;
_SetCNTR(wInterrupt_Mask);
return USB_SUCCESS;
}
uint32_t USB_SIL_Init(void)
{
/* USB interrupts initialization */
/* clear pending interrupts */
_SetISTR(0);
wInterrupt_Mask = IMR_MSK;
/* set interrupts mask */
_SetCNTR(wInterrupt_Mask);
return 0;
}
void Virtual_Com_Port_init(void)
{
/* Update the serial number string descriptor with the data from the unique
ID*/
Get_SerialNum();
pInformation->Current_Configuration = 0;
/* Connect the device */
PowerOn();
/* Perform basic device initialization operations */
USB_SIL_Init();
bDeviceState = UNCONNECTED;
}经过上面的配置，当USB设备端接入主机的时候，设备端的中断处理函数就能响应相应的中断请求，开始建立通信。
3.2 描述符讲解
描述符放在“usb_desc.c”和“usb_desc.h”文件中，更多细节参见USB — 初识USB协议（一）。
包含了设备的基本信息，比如USB版本号，端点0的传输大小，VID，PID，设备的类型等。
const uint8_t Virtual_Com_Port_DeviceDescriptor[] =
{
0x12, /* bLength */
USB_DEVICE_DESCRIPTOR_TYPE, /* bDescriptorType */
0x00,
0x02, /* bcdUSB = 2.00 */
0x02, /* bDeviceClass: CDC */
0x02, /* bDeviceSubClass */
0x02, /* bDeviceProtocol */
0x40, /* bMaxPacketSize0 */
0x83,
0x04, /* idVendor = 0x0483 */
0x40,
0x57, /* idProduct = 0x7540 */
0x00,
0x02, /* bcdDevice = 2.00 */
1, /* Index of string descriptor describing manufacturer */
2, /* Index of string descriptor describing product */
3, /* Index of string descriptor describing the device's serial number */
0x01 /* bNumConfigurations */
};配置描述符数组包含了配置描述符、接口描述符、功能描述符，端点描述符等，具体的描述符含义根据每种USB的CLASS不同而含义有所不同，后期小节会陆续讲解。
const uint8_t Virtual_Com_Port_ConfigDescriptor[] =
{
/*Configuration Descriptor*/
0x09, /* bLength: Configuration Descriptor size */
USB_CONFIGURATION_DESCRIPTOR_TYPE, /* bDescriptorType: Configuration */
VIRTUAL_COM_PORT_SIZ_CONFIG_DESC, /* wTotalLength:no of returned bytes */
0x00,
0x02, /* bNumInterfaces: 2 interface */
0x01, /* bConfigurationValue: Configuration value */
0x00, /* iConfiguration: Index of string descriptor describing the configuration */
0xC0, /* bmAttributes: self powered */
0x32, /* MaxPower 0 mA */
/*Interface Descriptor*/
0x09, /* bLength: Interface Descriptor size */
USB_INTERFACE_DESCRIPTOR_TYPE, /* bDescriptorType: Interface */
/* Interface descriptor type */
0x00, /* bInterfaceNumber: Number of Interface */
0x00, /* bAlternateSetting: Alternate setting */
0x01, /* bNumEndpoints: One endpoints used */
0x02, /* bInterfaceClass: Communication Interface Class */
0x02, /* bInterfaceSubClass: Abstract Control Model */
0x01, /* bInterfaceProtocol: Common AT commands */
0x00, /* iInterface: */
/*Header Functional Descriptor*/
0x05, /* bLength: Endpoint Descriptor size */
0x24, /* bDescriptorType: CS_INTERFACE */
0x00, /* bDescriptorSubtype: Header Func Desc */
0x10, /* bcdCDC: spec release number */
0x01,
/*Call Management Functional Descriptor*/
0x05, /* bFunctionLength */
0x24, /* bDescriptorType: CS_INTERFACE */
0x01, /* bDescriptorSubtype: Call Management Func Desc */
0x00, /* bmCapabilities: D0+D1 */
0x01, /* bDataInterface: 1 */
/*ACM Functional Descriptor*/
0x04, /* bFunctionLength */
0x24, /* bDescriptorType: CS_INTERFACE */
0x02, /* bDescriptorSubtype: Abstract Control Management desc */
0x02, /* bmCapabilities */
/*Union Functional Descriptor*/
0x05, /* bFunctionLength */
0x24, /* bDescriptorType: CS_INTERFACE */
0x06, /* bDescriptorSubtype: Union func desc */
0x00, /* bMasterInterface: Communication class interface */
0x01, /* bSlaveInterface0: Data Class Interface */
/*Endpoint 2 Descriptor*/
0x07, /* bLength: Endpoint Descriptor size */
USB_ENDPOINT_DESCRIPTOR_TYPE, /* bDescriptorType: Endpoint */
0x82, /* bEndpointAddress: (IN2) */
0x03, /* bmAttributes: Interrupt */
VIRTUAL_COM_PORT_INT_SIZE, /* wMaxPacketSize: */
0x00,
0xFF, /* bInterval: */
/*Data class interface descriptor*/
0x09, /* bLength: Endpoint Descriptor size */
USB_INTERFACE_DESCRIPTOR_TYPE, /* bDescriptorType: */
0x01, /* bInterfaceNumber: Number of Interface */
0x00, /* bAlternateSetting: Alternate setting */
0x02, /* bNumEndpoints: Two endpoints used */
0x0A, /* bInterfaceClass: CDC */
0x00, /* bInterfaceSubClass: */
0x00, /* bInterfaceProtocol: */
0x00, /* iInterface: */
/*Endpoint 3 Descriptor*/
0x07, /* bLength: Endpoint Descriptor size */
USB_ENDPOINT_DESCRIPTOR_TYPE, /* bDescriptorType: Endpoint */
0x03, /* bEndpointAddress: (OUT3) */
0x02, /* bmAttributes: Bulk */
VIRTUAL_COM_PORT_DATA_SIZE, /* wMaxPacketSize: */
0x00,
0x00, /* bInterval: ignore for Bulk transfer */
/*Endpoint 1 Descriptor*/
0x07, /* bLength: Endpoint Descriptor size */
USB_ENDPOINT_DESCRIPTOR_TYPE, /* bDescriptorType: Endpoint */
0x81, /* bEndpointAddress: (IN1) */
0x02, /* bmAttributes: Bulk */
VIRTUAL_COM_PORT_DATA_SIZE, /* wMaxPacketSize: */
0x00,
0x00 /* bInterval */
};其它描述符包括语言描述符，PID描述符、VID描述符，报告描述符等，这些描述符根据不同的厂商，不同的产品以及不同的USB应用而有所不通，我们会在后续的类容对这些描述符做一个简单的讲解。
3.3 中断处理函数
USB驱动最关键的部分在于中断处理函数部分，协议的大部分实现都是在中断中实现的，我们这里简单的讲解一下。首先进入USB中断处理函数，进入到USB_Istr()函数中去。
可以看到USB_Istr()函数实现了USB的中断的所有功能，我们这里只针对几个比较重要的函数进行讲解：
void USB_Istr(void)
{
uint32_t i = 0;
__IO uint32_t EP[8];
wIstr = _GetISTR();
#if (IMR_MSK & ISTR_SOF)
if (wIstr & ISTR_SOF & wInterrupt_Mask)
{
_SetISTR((uint16_t)CLR_SOF);
bIntPackSOF++;
#ifdef SOF_CALLBACK
SOF_Callback();
#endif
}
#endif
/*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*/
#if (IMR_MSK & ISTR_CTR)
if (wIstr & ISTR_CTR & wInterrupt_Mask)
{
/* servicing of the endpoint correct transfer interrupt */
/* clear of the CTR flag into the sub */
CTR_LP();
#ifdef CTR_CALLBACK
CTR_Callback();
#endif
}
#endif
/*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*/
#if (IMR_MSK & ISTR_RESET)
if (wIstr & ISTR_RESET & wInterrupt_Mask)
{
_SetISTR((uint16_t)CLR_RESET);
Device_Property.Reset();
#ifdef RESET_CALLBACK
RESET_Callback();
#endif
}
#endif
/*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*/
#if (IMR_MSK & ISTR_DOVR)
if (wIstr & ISTR_DOVR & wInterrupt_Mask)
{
_SetISTR((uint16_t)CLR_DOVR);
#ifdef DOVR_CALLBACK
DOVR_Callback();
#endif
}
#endif
/*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*/
#if (IMR_MSK & ISTR_ERR)
if (wIstr & ISTR_ERR & wInterrupt_Mask)
{
_SetISTR((uint16_t)CLR_ERR);
#ifdef ERR_CALLBACK
ERR_Callback();
#endif
}
#endif
/*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*/
#if (IMR_MSK & ISTR_WKUP)
if (wIstr & ISTR_WKUP & wInterrupt_Mask)
{
_SetISTR((uint16_t)CLR_WKUP);
Resume(RESUME_EXTERNAL);
#ifdef WKUP_CALLBACK
WKUP_Callback();
#endif
}
#endif
/*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*/
#if (IMR_MSK & ISTR_SUSP)
if (wIstr & ISTR_SUSP & wInterrupt_Mask)
{
/* check if SUSPEND is possible */
if (fSuspendEnabled)
{
Suspend();
}
else
{
/* if not possible then resume after xx ms */
Resume(RESUME_LATER);
}
/* clear of the ISTR bit must be done after setting of CNTR_FSUSP */
_SetISTR((uint16_t)CLR_SUSP);
#ifdef SUSP_CALLBACK
SUSP_Callback();
#endif
}
#endif
/*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*/
#if (IMR_MSK & ISTR_ESOF)
if (wIstr & ISTR_ESOF & wInterrupt_Mask)
{
/* clear ESOF flag in ISTR */
_SetISTR((uint16_t)CLR_ESOF);
if ((_GetFNR()&FNR_RXDP) != 0)
{
/* increment ESOF counter */
esof_counter ++;
/* test if we enter in ESOF more than 3 times with FSUSP =0 and RXDP =1=>> possible missing SUSP flag*/
if ((esof_counter > 3) && ((_GetCNTR()&CNTR_FSUSP) == 0))
{
/* this a sequence to apply a force RESET*/
/*Store CNTR value */
wCNTR = _GetCNTR();
/*Store endpoints registers status */
for (i = 0; i < 8; i++) EP[i] = _GetENDPOINT(i);
/*apply FRES */
wCNTR |= CNTR_FRES;
_SetCNTR(wCNTR);
/*clear FRES*/
wCNTR &= ~CNTR_FRES;
_SetCNTR(wCNTR);
/*poll for RESET flag in ISTR*/
while ((_GetISTR()&ISTR_RESET) == 0);
/* clear RESET flag in ISTR */
_SetISTR((uint16_t)CLR_RESET);
/*restore Enpoints*/
for (i = 0; i < 8; i++)
_SetENDPOINT(i, EP[i]);
esof_counter = 0;
}
}
else
{
esof_counter = 0;
}
/* resume handling timing is made with ESOFs */
Resume(RESUME_ESOF); /* request without change of the machine state */
#ifdef ESOF_CALLBACK
ESOF_Callback();
#endif
}
#endif
} /* USB_Istr */3.3.1 复位函数
复位是在USB识别到设备的时候，主机主动发出的特定序列，当USB设备收到这个特定序列的时候，就会产生中断相应，并进入中断中去处理相应的函数，这里的复位中断处理函数主要是配置端点的属性及端点的大小。
注意一下宏定义“BTABLE_ADDRESS”的对应的USB中断缓存区地址的偏移，也就是512Byte的RAM空间，宏“ENDP0_RXADDR”等是定义端点的发送和接收地址存放在RAM空间的具体位置，以“BTABLE_ADDRESS”为偏移。
/* buffer table base address */
/* buffer table base address */
#define BTABLE_ADDRESS (0x00)
/* EP0 */
/* rx/tx buffer base address */
#define ENDP0_RXADDR (0x40)
#define ENDP0_TXADDR (0x80)
/* EP1 */
/* tx buffer base address */
#define ENDP1_TXADDR (0xC0)
#define ENDP2_TXADDR (0x100)
#define ENDP3_RXADDR (0x110)
void Virtual_Com_Port_Reset(void)
{
/* Set Virtual_Com_Port DEVICE as not configured */
pInformation->Current_Configuration = 0;
/* Current Feature initialization */
pInformation->Current_Feature = Virtual_Com_Port_ConfigDescriptor[7];
/* Set Virtual_Com_Port DEVICE with the default Interface*/
pInformation->Current_Interface = 0;
SetBTABLE(BTABLE_ADDRESS);
/* Initialize Endpoint 0 */
SetEPType(ENDP0, EP_CONTROL);
SetEPTxStatus(ENDP0, EP_TX_STALL);
SetEPRxAddr(ENDP0, ENDP0_RXADDR);
SetEPTxAddr(ENDP0, ENDP0_TXADDR);
Clear_Status_Out(ENDP0);
SetEPRxCount(ENDP0, Device_Property.MaxPacketSize);
SetEPRxValid(ENDP0);
/* Initialize Endpoint 1 */
SetEPType(ENDP1, EP_BULK);
SetEPTxAddr(ENDP1, ENDP1_TXADDR);
SetEPTxStatus(ENDP1, EP_TX_NAK);
SetEPRxStatus(ENDP1, EP_RX_DIS);
/* Initialize Endpoint 2 */
SetEPType(ENDP2, EP_INTERRUPT);
SetEPTxAddr(ENDP2, ENDP2_TXADDR);
SetEPRxStatus(ENDP2, EP_RX_DIS);
SetEPTxStatus(ENDP2, EP_TX_NAK);
/* Initialize Endpoint 3 */
SetEPType(ENDP3, EP_BULK);
SetEPRxAddr(ENDP3, ENDP3_RXADDR);
SetEPRxCount(ENDP3, VIRTUAL_COM_PORT_DATA_SIZE);
SetEPRxStatus(ENDP3, EP_RX_VALID);
SetEPTxStatus(ENDP3, EP_TX_DIS);
/* Set this device to response on default address */
SetDeviceAddress(0);
bDeviceState = ATTACHED;
}3.3.2 正确传输完成函数
正确传输完成函数分为枚举过程（端点0）的正确传输完成函数和非端点0的正确传输完成函数。
void CTR_LP(void)
{
__IO uint16_t wEPVal = 0;
/* stay in loop while pending interrupts */
while (((wIstr = _GetISTR()) & ISTR_CTR) != 0)
{
/* extract highest priority endpoint number */
EPindex = (uint8_t)(wIstr & ISTR_EP_ID);
if (EPindex == 0)
{
/* Decode and service control endpoint interrupt */
/* calling related service routine */
/* (Setup0_Process, In0_Process, Out0_Process) */
/* save RX & TX status */
/* and set both to NAK */
SaveRState = _GetENDPOINT(ENDP0);
SaveTState = SaveRState & EPTX_STAT;
SaveRState &= EPRX_STAT;
_SetEPRxTxStatus(ENDP0, EP_RX_NAK, EP_TX_NAK);
/* DIR bit = origin of the interrupt */
if ((wIstr & ISTR_DIR) == 0)
{
/* DIR = 0 */
/* DIR = 0 => IN int */
/* DIR = 0 implies that (EP_CTR_TX = 1) always */
_ClearEP_CTR_TX(ENDP0);
In0_Process();
/* before terminate set Tx & Rx status */
_SetEPRxTxStatus(ENDP0, SaveRState, SaveTState);
return;
}
else
{
/* DIR = 1 */
/* DIR = 1 & CTR_RX => SETUP or OUT int */
/* DIR = 1 & (CTR_TX | CTR_RX) => 2 int pending */
wEPVal = _GetENDPOINT(ENDP0);
if ((wEPVal & EP_SETUP) != 0)
{
_ClearEP_CTR_RX(ENDP0); /* SETUP bit kept frozen while CTR_RX = 1 */
Setup0_Process();
/* before terminate set Tx & Rx status */
_SetEPRxTxStatus(ENDP0, SaveRState, SaveTState);
return;
}
else if ((wEPVal & EP_CTR_RX) != 0)
{
_ClearEP_CTR_RX(ENDP0);
Out0_Process();
/* before terminate set Tx & Rx status */
_SetEPRxTxStatus(ENDP0, SaveRState, SaveTState);
return;
}
}
}/* if(EPindex == 0) */
else
{
/* Decode and service non control endpoints interrupt */
/* process related endpoint register */
wEPVal = _GetENDPOINT(EPindex);
if ((wEPVal & EP_CTR_RX) != 0)
{
/* clear int flag */
_ClearEP_CTR_RX(EPindex);
/* call OUT service function */
(*pEpInt_OUT[EPindex - 1])();
} /* if((wEPVal & EP_CTR_RX) */
if ((wEPVal & EP_CTR_TX) != 0)
{
/* clear int flag */
_ClearEP_CTR_TX(EPindex);
/* call IN service function */
(*pEpInt_IN[EPindex - 1])();
} /* if((wEPVal & EP_CTR_TX) != 0) */
}/* if(EPindex == 0) else */
}/* while(...) */
}3.3.2.1 枚举过程正确传输完成函数
枚举过程的正确传输完成函数主要是接收SETUP指令请求，并相应的告知USB主机设备的描述符信息。
以下代码是处理USB主机的数据，把USB主机的SETUP请求数据存在pInformation结构体中，并在后续的函数进行指令的解析，并通过相对应的SETUP请求发送相对应的数据。
uint8_t Setup0_Process(void)
{
union
{
uint8_t* b;
uint16_t* w;
} pBuf;
#if defined STM32F303xE || defined STM32F302x8
uint16_t offset = 0;
pBuf.b = (uint8_t *)( PMAAddr + _GetEPRxAddr(ENDP0));
#else
uint16_t offset = 1;
pBuf.b = PMAAddr + (uint8_t *)(_GetEPRxAddr(ENDP0) * 2); /* *2 for 32 bits addr */
#endif
if (pInformation->ControlState != PAUSE)
{
pInformation->USBbmRequestType = *pBuf.b++; /* bmRequestType */
pInformation->USBbRequest = *pBuf.b++; /* bRequest */
pBuf.w += offset; /* word not accessed because of 32 bits addressing */
pInformation->USBwValue = ByteSwap(*pBuf.w++); /* wValue */
pBuf.w += offset; /* word not accessed because of 32 bits addressing */
pInformation->USBwIndex = ByteSwap(*pBuf.w++); /* wIndex */
pBuf.w += offset; /* word not accessed because of 32 bits addressing */
pInformation->USBwLength = *pBuf.w; /* wLength */
}
pInformation->ControlState = SETTING_UP;
if (pInformation->USBwLength == 0)
{
/* Setup with no data stage */
NoData_Setup0();
}
else
{
/* Setup with data stage */
Data_Setup0();
}
return Post0_Process();
}void Data_Setup0(void)
{
uint8_t *(*CopyRoutine)(uint16_t);
RESULT Result;
uint32_t Request_No = pInformation->USBbRequest;
uint32_t Related_Endpoint, Reserved;
uint32_t wOffset, Status;
CopyRoutine = NULL;
wOffset = 0;
/*GET DESCRIPTOR*/
if (Request_No == GET_DESCRIPTOR)
{
if (Type_Recipient == (STANDARD_REQUEST | DEVICE_RECIPIENT))
{
uint8_t wValue1 = pInformation->USBwValue1;
if (wValue1 == DEVICE_DESCRIPTOR)
{
CopyRoutine = pProperty->GetDeviceDescriptor;
}
#ifdef LPM_ENABLED
else if (wValue1 == DEVICE_BOS_DESCRIPTOR)
{
CopyRoutine = pProperty->GetBosDescriptor;
}
#endif
else if (wValue1 == CONFIG_DESCRIPTOR)
{
CopyRoutine = pProperty->GetConfigDescriptor;
}
else if (wValue1 == STRING_DESCRIPTOR)
{
CopyRoutine = pProperty->GetStringDescriptor;
} /* End of GET_DESCRIPTOR */
}
}
/*GET STATUS*/
else if ((Request_No == GET_STATUS) && (pInformation->USBwValue == 0)
&& (pInformation->USBwLength == 0x0002)
&& (pInformation->USBwIndex1 == 0))
{
/* GET STATUS for Device*/
if ((Type_Recipient == (STANDARD_REQUEST | DEVICE_RECIPIENT))
&& (pInformation->USBwIndex == 0))
{
CopyRoutine = Standard_GetStatus;
}
/* GET STATUS for Interface*/
else if (Type_Recipient == (STANDARD_REQUEST | INTERFACE_RECIPIENT))
{
if (((*pProperty->Class_Get_Interface_Setting)(pInformation->USBwIndex0, 0) == USB_SUCCESS)
&& (pInformation->Current_Configuration != 0))
{
CopyRoutine = Standard_GetStatus;
}
}
/* GET STATUS for EndPoint*/
else if (Type_Recipient == (STANDARD_REQUEST | ENDPOINT_RECIPIENT))
{
Related_Endpoint = (pInformation->USBwIndex0 & 0x0f);
Reserved = pInformation->USBwIndex0 & 0x70;
if (ValBit(pInformation->USBwIndex0, 7))
{
/*Get Status of endpoint & stall the request if the related_ENdpoint
is Disabled*/
Status = _GetEPTxStatus(Related_Endpoint);
}
else
{
Status = _GetEPRxStatus(Related_Endpoint);
}
if ((Related_Endpoint < Device_Table.Total_Endpoint) && (Reserved == 0)
&& (Status != 0))
{
CopyRoutine = Standard_GetStatus;
}
}
}
/*GET CONFIGURATION*/
else if (Request_No == GET_CONFIGURATION)
{
if (Type_Recipient == (STANDARD_REQUEST | DEVICE_RECIPIENT))
{
CopyRoutine = Standard_GetConfiguration;
}
}
/*GET INTERFACE*/
else if (Request_No == GET_INTERFACE)
{
if ((Type_Recipient == (STANDARD_REQUEST | INTERFACE_RECIPIENT))
&& (pInformation->Current_Configuration != 0) && (pInformation->USBwValue == 0)
&& (pInformation->USBwIndex1 == 0) && (pInformation->USBwLength == 0x0001)
&& ((*pProperty->Class_Get_Interface_Setting)(pInformation->USBwIndex0, 0) == USB_SUCCESS))
{
CopyRoutine = Standard_GetInterface;
}
}
if (CopyRoutine)
{
pInformation->Ctrl_Info.Usb_wOffset = wOffset;
pInformation->Ctrl_Info.CopyData = CopyRoutine;
/* sb in the original the cast to word was directly */
/* now the cast is made step by step */
(*CopyRoutine)(0);
Result = USB_SUCCESS;
}
else
{
Result = (*pProperty->Class_Data_Setup)(pInformation->USBbRequest);
if (Result == USB_NOT_READY)
{
pInformation->ControlState = PAUSE;
return;
}
}
if (pInformation->Ctrl_Info.Usb_wLength == 0xFFFF)
{
/* Data is not ready, wait it */
pInformation->ControlState = PAUSE;
return;
}
if ((Result == USB_UNSUPPORT) || (pInformation->Ctrl_Info.Usb_wLength == 0))
{
/* Unsupported request */
pInformation->ControlState = STALLED;
return;
}
if (ValBit(pInformation->USBbmRequestType, 7))
{
/* Device ==> Host */
__IO uint32_t wLength = pInformation->USBwLength;
/* Restrict the data length to be the one host asks for */
if (pInformation->Ctrl_Info.Usb_wLength > wLength)
{
pInformation->Ctrl_Info.Usb_wLength = wLength;
}
else if (pInformation->Ctrl_Info.Usb_wLength < pInformation->USBwLength)
{
if (pInformation->Ctrl_Info.Usb_wLength < pProperty->MaxPacketSize)
{
Data_Mul_MaxPacketSize = FALSE;
}
else if ((pInformation->Ctrl_Info.Usb_wLength % pProperty->MaxPacketSize) == 0)
{
Data_Mul_MaxPacketSize = TRUE;
}
}
pInformation->Ctrl_Info.PacketSize = pProperty->MaxPacketSize;
DataStageIn();
}
else
{
pInformation->ControlState = OUT_DATA;
vSetEPRxStatus(EP_RX_VALID); /* enable for next data reception */
}
return;
}3.3.2.2 非端点0正确传输完成函数
非控制端点0正确传输完成函数根据不同的USB应用存在不同的差距，但是主体框架已经完成，只需要用户在特定的框架中填写特定的程序即可。
比如当前程序只用到端点1的TX和端点3的RX，就只需要在端点1的TX和端点3的RX中编写相应的应用程序，其它端点不必理会。
/* associated to defined endpoints */
/*#define EP1_IN_Callback NOP_Process*/
#define EP2_IN_Callback NOP_Process
#define EP3_IN_Callback NOP_Process
#define EP4_IN_Callback NOP_Process
#define EP5_IN_Callback NOP_Process
#define EP6_IN_Callback NOP_Process
#define EP7_IN_Callback NOP_Process
#define EP1_OUT_Callback NOP_Process
#define EP2_OUT_Callback NOP_Process
/*#define EP3_OUT_Callback NOP_Process*/
#define EP4_OUT_Callback NOP_Process
#define EP5_OUT_Callback NOP_Process
#define EP6_OUT_Callback NOP_Process
#define EP7_OUT_Callback NOP_Process
void (*pEpInt_IN[7])(void) =
{
EP1_IN_Callback,
EP2_IN_Callback,
EP3_IN_Callback,
EP4_IN_Callback,
EP5_IN_Callback,
EP6_IN_Callback,
EP7_IN_Callback,
};
void (*pEpInt_OUT[7])(void) =
{
EP1_OUT_Callback,
EP2_OUT_Callback,
EP3_OUT_Callback,
EP4_OUT_Callback,
EP5_OUT_Callback,
EP6_OUT_Callback,
EP7_OUT_Callback,
};
void EP1_IN_Callback (void)
{
packet_sent = 1;
}
void EP3_OUT_Callback(void)
{
packet_receive = 1;
Receive_length = GetEPRxCount(ENDP3);
PMAToUserBufferCopy((unsigned char*)Receive_Buffer, ENDP3_RXADDR, Receive_length);
}到这里，本章就基本上讲完了，主要还是从应用的角度去简单的讲解了一下代码，如果读者需要更深入的了解代码的结构，还是需要大家仔细去学习USB的驱动源码的。
接下来讲解STM32 USB的虚拟串口环回功能实现，敬请期待。。。
