HID实例

键盘

电脑上使用hexdump查看键盘设备节点，输入a后，获得的原始HID数据如下：

sudo hexdump -e '8/1 " %02X" "\n"' /dev/hidraw1

Selection_286.png

第一行04代表a，这一行数据过来代表a键down的事件；
第二行全部00，这一行数据过来代表a键抬起的事件；
两行代表按键的操作流程。

当然使用usbhid-dump更为直观，如下所示：

Selection_287.png

触摸屏

Selection_288.png

描述符：

05 0d 09 04 a1 01 85 01 09 22 a1 02 09 42 15 00 25 01 75 01 95 01 81 02 95 07 81 03 26 ff 00 75 08 95 01 09 51 81 02 09 30 81 02 75 10 95 01 05 01 55 0f 65 11 26 00 04 35 00 46 ff ff 09 30 81 02 46 ff ff 26 58 02 09 31 81 02 c0 05 0d 55 0c 66 01 10 47 ff ff 00 00 27 ff ff 00 00 75 10 95 01 09 56 81 02 05 0d 09 54 25 7f 95 01 75 08 81 02 85 02 09 55 95 01 25 02 b1 02 c0 

  INPUT(1)[INPUT]
    Field(0)
      Logical(Digitizers.Finger)
      Application(Digitizers.TouchScreen)
      Usage(1)
        Digitizers.TipSwitch
      Logical Minimum(0)
      Logical Maximum(1)
      Report Size(1)
      Report Count(1)
      Report Offset(0)
      Flags( Variable Absolute )
    Field(1)
      Logical(Digitizers.Finger)
      Application(Digitizers.TouchScreen)
      Usage(1)
        Digitizers.ContactID
      Logical Minimum(0)
      Logical Maximum(255)
      Report Size(8)
      Report Count(1)
      Report Offset(8)
      Flags( Variable Absolute )
    Field(2)
      Logical(Digitizers.Finger)
      Application(Digitizers.TouchScreen)
      Usage(1)
        Digitizers.TipPressure
      Logical Minimum(0)
      Logical Maximum(255)
      Report Size(8)
      Report Count(1)
      Report Offset(16)
      Flags( Variable Absolute )
    Field(3)
      Logical(Digitizers.Finger)
      Application(Digitizers.TouchScreen)
      Usage(1)
        GenericDesktop.X
      Logical Minimum(0)
      Logical Maximum(1024)
      Physical Minimum(0)
      Physical Maximum(65535)
      Unit Exponent(-1)
      Unit(SI Linear : Centimeter)
      Report Size(16)
      Report Count(1)
      Report Offset(24)
      Flags( Variable Absolute )
    Field(4)
      Logical(Digitizers.Finger)
      Application(Digitizers.TouchScreen)
      Usage(1)
        GenericDesktop.Y
      Logical Minimum(0)
      Logical Maximum(600)
      Physical Minimum(0)
      Physical Maximum(65535)
      Unit Exponent(-1)
      Unit(SI Linear : Centimeter)
      Report Size(16)
      Report Count(1)
      Report Offset(40)
      Flags( Variable Absolute )
    Field(5)
      Application(Digitizers.TouchScreen)
      Usage(1)
        Digitizers.0056
      Logical Minimum(0)
      Logical Maximum(65535)
      Physical Minimum(0)
      Physical Maximum(65535)
      Unit Exponent(-4)
      Unit(SI Linear : Seconds)
      Report Size(16)
      Report Count(1)
      Report Offset(56)
      Flags( Variable Absolute )
    Field(6)
      Application(Digitizers.TouchScreen)
      Usage(1)
        Digitizers.ContactCount
      Logical Minimum(0)
      Logical Maximum(127)
      Physical Minimum(0)
      Physical Maximum(65535)
      Unit Exponent(-4)
      Unit(SI Linear : Seconds)
      Report Size(8)
      Report Count(1)
      Report Offset(72)
      Flags( Variable Absolute )
  FEATURE(2)[FEATURE]
    Field(0)
      Application(Digitizers.TouchScreen)
      Usage(1)
        Digitizers.ContactMaximumNumber
      Logical Minimum(0)
      Logical Maximum(2)
      Physical Minimum(0)
      Physical Maximum(65535)
      Unit Exponent(-4)
      Unit(SI Linear : Seconds)
      Report Size(8)
      Report Count(1)
      Report Offset(0)
      Flags( Variable Absolute )

Digitizers.TipSwitch ---> Key.Touch
Digitizers.ContactID ---> Sync.Report
Digitizers.TipPressure ---> Absolute.?
GenericDesktop.X ---> Absolute.MTPositionX
GenericDesktop.Y ---> Absolute.MTPositionY
Digitizers.0056 ---> Absolute.Misc
Digitizers.ContactCount ---> Sync.Report

将描述符和输入事件对应起来：

Selection_291.png