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我有一个带 USB 的数字声级计（声压计）GM1356。有一些软件可以在 Windows 上处理它，但是我没有 CD，而且它在 Internet 上不可用。我想要做的是读取它关于 Linux 上当前噪音水平的数据。

我已经找到了一个库，它允许我用我知道的语言（ruby、libusb）来执行此操作。在下一步中，我安装了wireshark 来检查它发送给电脑的内容。它不会发送太多。我发现的最有趣的数据包是DESCRIPTOR HID Report. 我想知道下一步应该采取哪些步骤来读取我感兴趣的数据。我如何确定我应该发送哪些请求来获取它？

HID Report
    Global item (Usage)
        Header
            .... ..10 = bSize: 2 bytes (2)
            .... 01.. = bType: Global (1)
            0000 .... = bTag: Usage (0x0)
        Usage page: [Vendor-defined] (0xffa0)
    Local item (Usage)
        Header
            .... ..01 = bSize: 1 byte (1)
            .... 10.. = bType: Local (2)
            0000 .... = bTag: Usage (0x0)
        Usage: [Vendor-defined] (0xffa00001)
    Main item (Collection)
        Header
            .... ..01 = bSize: 1 byte (1)
            .... 00.. = bType: Main (0)
            1010 .... = bTag: Collection (0xa)
        Collection type: Application (0x01)
        Local item (Usage)
            Header
                .... ..01 = bSize: 1 byte (1)
                .... 10.. = bType: Local (2)
                0000 .... = bTag: Usage (0x0)
            Usage: [Vendor-defined] (0xffa00002)
        Main item (Collection)
            Header
                .... ..01 = bSize: 1 byte (1)
                .... 00.. = bType: Main (0)
                1010 .... = bTag: Collection (0xa)
            Collection type: Physical (0x00)
            Global item (Usage)
                Header
                    .... ..10 = bSize: 2 bytes (2)
                    .... 01.. = bType: Global (1)
                    0000 .... = bTag: Usage (0x0)
                Usage page: [Vendor-defined] (0xffa1)
            Local item (Usage)
                Header
                    .... ..01 = bSize: 1 byte (1)
                    .... 10.. = bType: Local (2)
                    0000 .... = bTag: Usage (0x0)
                Usage: [Vendor-defined] (0xffa10003)
            Local item (Usage)
                Header
                    .... ..01 = bSize: 1 byte (1)
                    .... 10.. = bType: Local (2)
                    0000 .... = bTag: Usage (0x0)
                Usage: [Vendor-defined] (0xffa10004)
            Global item (Logical minimum)
                Header
                    .... ..01 = bSize: 1 byte (1)
                    .... 01.. = bType: Global (1)
                    0001 .... = bTag: Logical minimum (0x1)
                Logical minimum: 128
            Global item (Logical maximum)
                Header
                    .... ..01 = bSize: 1 byte (1)
                    .... 01.. = bType: Global (1)
                    0010 .... = bTag: Logical maximum (0x2)
                Logical maximum: 127
            Global item (Physical minimum)
                Header
                    .... ..01 = bSize: 1 byte (1)
                    .... 01.. = bType: Global (1)
                    0011 .... = bTag: Physical minimum (0x3)
                Physical minimum: 0
            Global item (Physical maximum)
                Header
                    .... ..01 = bSize: 1 byte (1)
                    .... 01.. = bType: Global (1)
                    0100 .... = bTag: Physical maximum (0x4)
                Physical maximum: 255
            Global item (Report size)
                Header
                    .... ..01 = bSize: 1 byte (1)
                    .... 01.. = bType: Global (1)
                    0111 .... = bTag: Report size (0x7)
                Report size: 8
            Global item (Report count)
                Header
                    .... ..01 = bSize: 1 byte (1)
                    .... 01.. = bType: Global (1)
                    1001 .... = bTag: Report count (0x9)
                Report count: 8
            Main item (Input)
                Header
                    .... ..01 = bSize: 1 byte (1)
                    .... 00.. = bType: Main (0)
                    1000 .... = bTag: Input (0x8)
                .... .... 0 = Data/constant: Data
                .... ...1 . = Data type: Variable
                .... ..0. . = Coordinates: Absolute
                .... .0.. . = Min/max wraparound: No Wrap
                .... 0... . = Physical relationship to data: Linear
                ...0 .... . = Preferred state: Preferred State
                ..0. .... . = Has null position: No Null position
                .0.. .... . = [Reserved]: False
                0... .... . = Bits or bytes: Buffered bytes (default, no second byte present)
            Local item (Usage)
                Header
                    .... ..01 = bSize: 1 byte (1)
                    .... 10.. = bType: Local (2)
                    0000 .... = bTag: Usage (0x0)
                Usage: [Vendor-defined] (0xffa10005)
            Local item (Usage)
                Header
                    .... ..01 = bSize: 1 byte (1)
                    .... 10.. = bType: Local (2)
                    0000 .... = bTag: Usage (0x0)
                Usage: [Vendor-defined] (0xffa10006)
            Global item (Logical minimum)
                Header
                    .... ..01 = bSize: 1 byte (1)
                    .... 01.. = bType: Global (1)
                    0001 .... = bTag: Logical minimum (0x1)
                Logical minimum: 128
            Global item (Logical maximum)
                Header
                    .... ..01 = bSize: 1 byte (1)
                    .... 01.. = bType: Global (1)
                    0010 .... = bTag: Logical maximum (0x2)
                Logical maximum: 127
            Global item (Physical minimum)
                Header
                    .... ..01 = bSize: 1 byte (1)
                    .... 01.. = bType: Global (1)
                    0011 .... = bTag: Physical minimum (0x3)
                Physical minimum: 0
            Global item (Physical maximum)
                Header
                    .... ..01 = bSize: 1 byte (1)
                    .... 01.. = bType: Global (1)
                    0100 .... = bTag: Physical maximum (0x4)
                Physical maximum: 255
            Global item (Report size)
                Header
                    .... ..01 = bSize: 1 byte (1)
                    .... 01.. = bType: Global (1)
                    0111 .... = bTag: Report size (0x7)
                Report size: 8
            Global item (Report count)
                Header
                    .... ..01 = bSize: 1 byte (1)
                    .... 01.. = bType: Global (1)
                    1001 .... = bTag: Report count (0x9)
                Report count: 8
            Main item (Output)
                Header
                    .... ..01 = bSize: 1 byte (1)
                    .... 00.. = bType: Main (0)
                    1001 .... = bTag: Output (0x9)
                .... .... 0 = Data/constant: Data
                .... ...1 . = Data type: Variable
                .... ..0. . = Coordinates: Absolute
                .... .0.. . = Min/max wraparound: No Wrap
                .... 0... . = Physical relationship to data: Linear
                ...0 .... . = Preferred state: Preferred State
                ..0. .... . = Has null position: No Null position
                .0.. .... . = (Non)-volatile: Non Volatile
                0... .... . = Bits or bytes: Buffered bytes (default, no second byte present)
            Main item (End collection)
                Header
                    .... ..00 = bSize: 0 bytes (0)
                    .... 00.. = bType: Main (0)
                    1100 .... = bTag: End collection (0xc)
        Main item (End collection)
            Header
                .... ..00 = bSize: 0 bytes (0)
                .... 00.. = bType: Main (0)
                1100 .... = bTag: End collection (0xc)
4

2 回答 2

1

当您解码 HID 描述符时，它将显示数据包格式。不幸的是，在这种情况下，使用页面是供应商定义的，因此无法准确说明如何解释每个使用。

我使用hidrdd对其进行了解码（免责声明：我编写了它，但它是免费开源的，所以我没有利益冲突）为：

//--------------------------------------------------------------------------------
// Decoded Application Collection
//--------------------------------------------------------------------------------

/*
06 A0FF      (GLOBAL) USAGE_PAGE         0xFFA0 Vendor-defined 
09 01        (LOCAL)  USAGE              0xFFA00001 <-- Warning: Undocumented usage (document it by inserting 0001 into file FFA0.conf)
A1 01        (MAIN)   COLLECTION         0x01 Application (Usage=0xFFA00001: Page=Vendor-defined, Usage=, Type=) <-- Error: COLLECTION must be preceded by a known USAGE
09 02          (LOCAL)  USAGE              0xFFA00002 <-- Warning: Undocumented usage (document it by inserting 0002 into file FFA0.conf)
A1 00          (MAIN)   COLLECTION         0x00 Physical (Usage=0xFFA00002: Page=Vendor-defined, Usage=, Type=) <-- Error: COLLECTION must be preceded by a known USAGE
06 A1FF          (GLOBAL) USAGE_PAGE         0xFFA1 Vendor-defined 
09 03            (LOCAL)  USAGE              0xFFA10003 <-- Warning: Undocumented usage (document it by inserting 0003 into file FFA1.conf)
09 04            (LOCAL)  USAGE              0xFFA10004 <-- Warning: Undocumented usage (document it by inserting 0004 into file FFA1.conf)
15 80            (GLOBAL) LOGICAL_MINIMUM    0x80 (-128)  
25 7F            (GLOBAL) LOGICAL_MAXIMUM    0x7F (127)  
35 00            (GLOBAL) PHYSICAL_MINIMUM   0x00 (0)  <-- Info: Consider replacing 35 00 with 34
45 FF            (GLOBAL) PHYSICAL_MAXIMUM   0xFF (-1)  
75 08            (GLOBAL) REPORT_SIZE        0x08 (8) Number of bits per field  
95 08            (GLOBAL) REPORT_COUNT       0x08 (8) Number of fields  
81 02            (MAIN)   INPUT              0x00000002 (8 fields x 8 bits) 0=Data 1=Variable 0=Absolute 0=NoWrap 0=Linear 0=PrefState 0=NoNull 0=NonVolatile 0=Bitmap  <-- Error: PHYSICAL_MAXIMUM (-1) is less than PHYSICAL_MINIMUM (0)
09 05            (LOCAL)  USAGE              0xFFA10005 <-- Warning: Undocumented usage (document it by inserting 0005 into file FFA1.conf)
09 06            (LOCAL)  USAGE              0xFFA10006 <-- Warning: Undocumented usage (document it by inserting 0006 into file FFA1.conf)
15 80            (GLOBAL) LOGICAL_MINIMUM    0x80 (-128) <-- Redundant: LOGICAL_MINIMUM is already -128 
25 7F            (GLOBAL) LOGICAL_MAXIMUM    0x7F (127) <-- Redundant: LOGICAL_MAXIMUM is already 127 
35 00            (GLOBAL) PHYSICAL_MINIMUM   0x00 (0) <-- Redundant: PHYSICAL_MINIMUM is already 0 <-- Info: Consider replacing 35 00 with 34
45 FF            (GLOBAL) PHYSICAL_MAXIMUM   0xFF (-1) <-- Redundant: PHYSICAL_MAXIMUM is already -1 
75 08            (GLOBAL) REPORT_SIZE        0x08 (8) Number of bits per field <-- Redundant: REPORT_SIZE is already 8 
95 08            (GLOBAL) REPORT_COUNT       0x08 (8) Number of fields <-- Redundant: REPORT_COUNT is already 8 
91 02            (MAIN)   OUTPUT             0x00000002 (8 fields x 8 bits) 0=Data 1=Variable 0=Absolute 0=NoWrap 0=Linear 0=PrefState 0=NoNull 0=NonVolatile 0=Bitmap  <-- Error: PHYSICAL_MAXIMUM (-1) is less than PHYSICAL_MINIMUM (0)
C0             (MAIN)   END_COLLECTION     Physical  <-- Warning: Physical units are still in effect PHYSICAL(MIN=0,MAX=-1) UNIT(0x,EXP=0)
C0           (MAIN)   END_COLLECTION     Application  <-- Warning: Physical units are still in effect PHYSICAL(MIN=0,MAX=-1) UNIT(0x,EXP=0)
*/

//--------------------------------------------------------------------------------
// Vendor-defined inputReport (Device --> Host)
//--------------------------------------------------------------------------------

typedef struct
{
                                                     // No REPORT ID byte
                                                     // Collection: CA: CP:
  int8_t   VEN_0003;                                 // Usage 0xFFA10003: , Value = -128 to 127, Physical = (Value + 128) x -1 / 255
  int8_t   VEN_0004[7];                              // Usage 0xFFA10004: , Value = -128 to 127, Physical = (Value + 128) x -1 / 255
} inputReport_t;


//--------------------------------------------------------------------------------
// Vendor-defined outputReport (Device <-- Host)
//--------------------------------------------------------------------------------

typedef struct
{
                                                     // No REPORT ID byte
                                                     // Collection: CA: CP:
  int8_t   VEN_0005;                                 // Usage 0xFFA10005: , Value = -128 to 127, Physical = (Value + 128) x -1 / 255
  int8_t   VEN_0006[7];                              // Usage 0xFFA10006: , Value = -128 to 127, Physical = (Value + 128) x -1 / 255
} outputReport_t;

正如你所看到的，上面的 HID 描述符有一些问题（例如，物理最大 45 FF 是 -1，但我认为它们的意思是 255 - 应该表示为 46 FF 00）但问题仍然是它没有告诉你任何关于用法的意义。顺便说一句，即使 Wireshark 也没有正确报告逻辑最小值：15 80 是 -128 而不是 128。

我们可以从中看出，报告有 8 个字节长，而且第一个字节似乎是某种 id（嗯，它的用法与剩余的 7 个字节不同）。

只有供应商的驱动程序知道如何解释报告，但是在受控条件下获得足够数量的 Wireshark 数据包捕获，您可能能够反向工程一个可行的解释。

对不起，但这是我能做的最好的。

于 2019-05-29T07:57:15.300 回答
0

我也买了一个分贝计，正好和你的型号兼容。我目前正在尝试将此代码移植到 bash 脚本：https ://github.com/dobra-noc/gm1356这对我的设备来说很好（顺便说一句，它甚至不是 gm1356）我猜它也会为你工作。

于 2020-05-04T23:01:20.067 回答