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ARM DIY进程11:USB虚拟鼠标
   
         练习利用开发板上的USB接口实现免驱动鼠标功能，免驱动鼠标属于人机交互设备HID。本次练习需要4只按键实现鼠标光标上下左右移动，开发板上的按键接口太少，只好在板外另外搭接4只按键使用，见图1。在开发板上“USB_Disconnect”通过JP2连接到GPIOA_10注明缺省状态为“Open”，此时T1(9013)由于B极0偏置故C-E极截至，USB接口第3脚D+将为0V,PC机将认不到插入的USB设备。所以要么将JP2短接，并在程序中设PA10为输出口并输出高电平，要么直接将R47接JP2端连接到3.3V或干脆将T1的C-E极直接短路来调试（图3）。
       说实在话，这个USB从底层一直到用户层，实在是太复杂了，要弄通它不是几个练习就可以做到的。本次练习只不过是发挥了DIY者的的特长：COPY+PASTE东拼西凑完成的，详细原理在此就不敢班门弄斧了。从ST官方网站下载的MDK例程JoStickMouse在开发板上都无法成功运行。本例程是移植了ST官方IAR的例程的。运行后仿真环境就无法进入DEBUG跟踪、断点了。当虚拟鼠标USB设备被PC识别后，在WindowsXP设备管理器里会增加一个USB人体学输入设备（图4图5）,这时按UP、DN、RIGTH、LEFT其中一键屏幕上的鼠标会朝不同方向移动，移动的速度可在"HW_CONFIG.H"头文件的CURSOR_STEP变量中重新定义。有时侯增加的USB人体学输入设备会出现黄色问号警告，只要拔去USB连接线，把这个设备卸载，然后重新插上USB连接线，系统就会自动安装新设备正常工作了。


                          图1



                         图2

关键代码
"hw_config.c"
#include "STM32Lib\\stm32f10x.h"
#include "hw_config.h"
#include "STM32Lib\\usblib\\usb_lib.h"
#include "usb_desc.h"
#include "platform_config.h"
#include "usb_pwr.h"

ErrorStatus HSEStartUpStatus;
EXTI_InitTypeDef EXTI_InitStructure;

void Set_System(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;

  SystemInit();

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, ENABLE);
  GPIO_AINConfig();

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIO_DISCONNECT, ENABLE);

  /* USB_DISCONNECT used as USB pull-up */
  GPIO_InitStructure.GPIO_Pin = USB_DISCONNECT_PIN;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
  GPIO_Init(USB_DISCONNECT, &GPIO_InitStructure);

  /* Enable Joystick GPIOs clock */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIO_JOY_SET1, ENABLE);
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIO_JOY_SET2, ENABLE);

  /* Configure the JoyStick IOs */这里配置IO口的方法又有新意
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_UP;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
  GPIO_Init(GPIO_UP, &GPIO_InitStructure);

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_DOWN;
  GPIO_Init(GPIO_DOWN, &GPIO_InitStructure);

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_LEFT;
  GPIO_Init(GPIO_LEFT, &GPIO_InitStructure);

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_RIGHT;
  GPIO_Init(GPIO_RIGHT, &GPIO_InitStructure);

  /* Enable GPIOB & AFIO clocks */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIO_KEY | RCC_APB2Periph_AFIO, ENABLE);

  /* Configure the Key pin as input floating */ /* used for remote wakeup */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_KEY;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
  GPIO_Init(GPIO_KEY, &GPIO_InitStructure);
  GPIO_EXTILineConfig(GPIO_KEY_PORTSOURCE, GPIO_KEY_PINSOURCE);  /* Connect EXTI Line9 */
  EXTI_InitStructure.EXTI_Line = GPIO_KEY_EXTI_Line;    /* Configure EXTI Line9 to generate an interrupt on falling edge */
  EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
  EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;
  EXTI_InitStructure.EXTI_LineCmd = ENABLE;
  EXTI_Init(&EXTI_InitStructure);      

  /* used for USB resume interrupt */
  EXTI_ClearITPendingBit(EXTI_Line18); 
  EXTI_InitStructure.EXTI_Line = EXTI_Line18;
  EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising;
  EXTI_InitStructure.EXTI_LineCmd = ENABLE;
  EXTI_Init(&EXTI_InitStructure);

  EXTI_ClearITPendingBit(GPIO_KEY_EXTI_Line);
}

/*******************************************************************************
* Function Name  : Set_USBClock
* Description    : Configures USB Clock input (48MHz).
* Input          : None.
* Output         : None.
* Return         : None.
*******************************************************************************/
void Set_USBClock(void)
{
  /* Select USBCLK source */
  RCC_USBCLKConfig(RCC_USBCLKSource_PLLCLK_1Div5);

  /* Enable USB clock */
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_USB, ENABLE);
}

/*******************************************************************************
* Function Name  : GPIO_AINConfig
* Description    : Configures all IOs as AIN to reduce the power consumption.
* Input          : None.
* Output         : None.
* Return         : None.
*******************************************************************************/
void GPIO_AINConfig(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;

  /* Enable all GPIOs Clock*/
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_ALLGPIO, ENABLE);

  /* Configure all GPIO port pins in Analog Input mode (floating input trigger OFF) */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_All;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
  GPIO_Init(GPIOA, &GPIO_InitStructure);
  GPIO_Init(GPIOB, &GPIO_InitStructure);
  GPIO_Init(GPIOC, &GPIO_InitStructure);
  GPIO_Init(GPIOD, &GPIO_InitStructure);
  GPIO_Init(GPIOE, &GPIO_InitStructure);

  /* Disable all GPIOs Clock*/
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_ALLGPIO, DISABLE);
}
/*******************************************************************************
* Function Name  : Enter_LowPowerMode.
* Description    : Power-off system clocks and power while entering suspend mode.
* Input          : None.
* Output         : None.
* Return         : None.
*******************************************************************************/
void Enter_LowPowerMode(void)
{
  /* Set the device state to suspend */
  bDeviceState = SUSPENDED;

  /* Clear EXTI Line18 pending bit */
  EXTI_ClearITPendingBit(GPIO_KEY_EXTI_Line);

  /* Request to enter STOP mode with regulator in low power mode */
  PWR_EnterSTOPMode(PWR_Regulator_LowPower, PWR_STOPEntry_WFI);
}

/*******************************************************************************
* Function Name  : Leave_LowPowerMode.
* Description    : Restores system clocks and power while exiting suspend mode.
* Input          : None.
* Output         : None.
* Return         : None.
*******************************************************************************/
void Leave_LowPowerMode(void)
{
  DEVICE_INFO *pInfo = &Device_Info;

  /* Enable HSE */
  RCC_HSEConfig(RCC_HSE_ON);

  /* Wait till HSE is ready */
  HSEStartUpStatus = RCC_WaitForHSEStartUp();

  /* Enable PLL */
  RCC_PLLCmd(ENABLE);

  /* Wait till PLL is ready */
  while (RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET)
  {}

  /* Select PLL as system clock source */
  RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);

  /* Wait till PLL is used as system clock source */
  while (RCC_GetSYSCLKSource() != 0x08)
  {}

  /* Set the device state to the correct state */
  if (pInfo->Current_Configuration != 0)
  {
    /* Device configured */
    bDeviceState = CONFIGURED;
  }
  else
  {
    bDeviceState = ATTACHED;
  }
}

/*******************************************************************************
* Function Name  : USB_Interrupts_Config.
* Description    : Configures the USB interrupts.
* Input          : None.
* Output         : None.
* Return         : None.
*******************************************************************************/
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 = 1;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
  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 = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);

  /* Enable the Key EXTI line Interrupt */
  NVIC_InitStructure.NVIC_IRQChannel = EXTI_KEY_IRQChannel;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
}

/*******************************************************************************
* Function Name  : USB_Cable_Config.
* Description    : Software Connection/Disconnection of USB Cable.
* Input          : NewState: new state.
* Output         : None.
* Return         : None
*******************************************************************************/
void USB_Cable_Config (FunctionalState NewState)
{
  if (NewState == DISABLE)
  {
    GPIO_ResetBits(USB_DISCONNECT, USB_DISCONNECT_PIN);
  }
  else
  {
    GPIO_SetBits(USB_DISCONNECT, USB_DISCONNECT_PIN);
  }
}

/*******************************************************************************
* Function Name : JoyState.
* Description   : Decodes the Joystick direction.
* Input         : None.
* Output        : None.
* Return value  : The direction value.
*******************************************************************************/
uint8_t JoyState(void)
{
  /* "right" key is pressed */
  if (!GPIO_ReadInputDataBit(GPIO_RIGHT, GPIO_Pin_RIGHT))
  {
    return RIGHT;
  }
  /* "left" key is pressed */
  if (!GPIO_ReadInputDataBit(GPIO_LEFT, GPIO_Pin_LEFT))
  {
    return LEFT;
  }
  /* "up" key is pressed */
  if (!GPIO_ReadInputDataBit(GPIO_UP, GPIO_Pin_UP))
  {
    return UP;
  }
  /* "down" key is pressed */
  if (!GPIO_ReadInputDataBit(GPIO_DOWN, GPIO_Pin_DOWN))
  {
    return DOWN;
  }
  /* No key is pressed */
  else
  {
    return 0;
  }
}

/*******************************************************************************
* Function Name : Joystick_Send.
* Description   : prepares buffer to be sent containing Joystick event infos.
* Input         : Keys: keys received from terminal.
* Output        : None.
* Return value  : None.
*******************************************************************************/
void Joystick_Send(uint8_t Keys)
{
  uint8_t Mouse_Buffer[4] = {0, 0, 0, 0};
  int8_t X = 0, Y = 0;

  switch (Keys)
  {
    case LEFT:
      X -= CURSOR_STEP;
      break;
    case RIGHT:

      X += CURSOR_STEP;
      break;
    case UP:
      Y -= CURSOR_STEP;
      break;
    case DOWN:
      Y += CURSOR_STEP;
      break;
    default:
      return;
  }

  /* prepare buffer to send */
  Mouse_Buffer[1] = X;
  Mouse_Buffer[2] = Y;
  /*copy mouse position info in ENDP1 Tx Packet Memory Area*/
  UserToPMABufferCopy(Mouse_Buffer, GetEPTxAddr(ENDP1), 4);
  /* enable endpoint for transmission */
  SetEPTxValid(ENDP1);
}

/*******************************************************************************
* Function Name  : Get_SerialNum.
* Description    : Create the serial number string descriptor.
* Input          : None.
* Output         : None.
* Return         : None.
*******************************************************************************/
void Get_SerialNum(void)
{
  uint32_t Device_Serial0, Device_Serial1, Device_Serial2;

  Device_Serial0 = *(uint32_t*)(0x1FFFF7E8);
  Device_Serial1 = *(uint32_t*)(0x1FFFF7EC);
  Device_Serial2 = *(uint32_t*)(0x1FFFF7F0);

  if (Device_Serial0 != 0)
  {
    Joystick_StringSerial[2] = (uint8_t)(Device_Serial0 & 0x000000FF);
    Joystick_StringSerial[4] = (uint8_t)((Device_Serial0 & 0x0000FF00) >> 8);
    Joystick_StringSerial[6] = (uint8_t)((Device_Serial0 & 0x00FF0000) >> 16);
    Joystick_StringSerial[8] = (uint8_t)((Device_Serial0 & 0xFF000000) >> 24);

    Joystick_StringSerial[10] = (uint8_t)(Device_Serial1 & 0x000000FF);
    Joystick_StringSerial[12] = (uint8_t)((Device_Serial1 & 0x0000FF00) >> 8);
    Joystick_StringSerial[14] = (uint8_t)((Device_Serial1 & 0x00FF0000) >> 16);
    Joystick_StringSerial[16] = (uint8_t)((Device_Serial1 & 0xFF000000) >> 24);

    Joystick_StringSerial[18] = (uint8_t)(Device_Serial2 & 0x000000FF);
    Joystick_StringSerial[20] = (uint8_t)((Device_Serial2 & 0x0000FF00) >> 8);
    Joystick_StringSerial[22] = (uint8_t)((Device_Serial2 & 0x00FF0000) >> 16);
    Joystick_StringSerial[24] = (uint8_t)((Device_Serial2 & 0xFF000000) >> 24);
  }
}

"platform_config.h"
#ifndef __PLATFORM_CONFIG_H
#define __PLATFORM_CONFIG_H

   used to run the example */

  #define USB_DISCONNECT                      GPIOA
  #define USB_DISCONNECT_PIN                  GPIO_Pin_8
 
  #define RCC_APB2Periph_GPIO_DISCONNECT      RCC_APB2Periph_GPIOA
  #define RCC_APB2Periph_GPIO_KEY             RCC_APB2Periph_GPIOB

 #define GPIO_Pin_KEY                        GPIO_Pin_11  //按键口在这里定义
 #define GPIO_Pin_UP                         GPIO_Pin_6
  #define GPIO_Pin_DOWN                       GPIO_Pin_7
  #define GPIO_Pin_LEFT                       GPIO_Pin_13 
  #define GPIO_Pin_RIGHT                      GPIO_Pin_15 

  #define RCC_APB2Periph_GPIO_JOY_SET1        RCC_APB2Periph_GPIOC
  #define RCC_APB2Periph_GPIO_JOY_SET2        RCC_APB2Periph_GPIOB 

   #define GPIO_RIGHT                          GPIOC
  #define GPIO_LEFT                           GPIOC
  #define GPIO_DOWN                           GPIOA
  #define GPIO_UP                             GPIOC
  #define GPIO_KEY                            GPIOB

  #define GPIO_KEY_PORTSOURCE                 GPIO_PortSourceGPIOB
  #define GPIO_KEY_PINSOURCE                  GPIO_PinSource7
  #define GPIO_KEY_EXTI_Line                  EXTI_Line7

  #define EXTI_KEY_IRQChannel                 EXTI9_5_IRQn

  #define RCC_APB2Periph_ALLGPIO             (RCC_APB2Periph_GPIOA \
                                              | RCC_APB2Periph_GPIOB \
                                              | RCC_APB2Periph_GPIOC \
                                              | RCC_APB2Periph_GPIOD \
                                              | RCC_APB2Periph_GPIOE )

#endif /* __PLATFORM_CONFIG_H */