[参考译文] TM4C123GE6PM：USB 比较器冲突 差 文档

https://e2e.ti.com/support/microcontrollers/arm-based-microcontrollers-group/arm-based-microcontrollers/f/arm-based-microcontrollers-forum/1241317/tm4c123ge6pm-conflicting-usb-comp-dev-documentation

您好！

我必须为123GX LaunchPad 运行 USB 项目、并且试着将这两个 USB 项目组合成一个复合器件。  阅读了几天的文档和 usblib 源代码后、我遇到了看起来存在冲突的信息-或者我很困惑。

我在这里看到 usblib 用户指南说您需要支持3个有道理的字符串(如下所示)：

但当我查看源代码时、它需要的不止这些。  请参见下方的。

    //
    //! A pointer to the string descriptor array for this device.  This array
    //! must contain the following string descriptor pointers in this order.
    //! Language descriptor, Manufacturer name string (language 1), Product
    //! name string (language 1), Serial number string (language 1), Composite
    //! device interface description string (language 1), Configuration
    //! description string (language 1).
    //!
    //! If supporting more than 1 language, the descriptor block (except for
    //! string descriptor 0) must be repeated for each language defined in the
    //! language descriptor.
    //!
    //
    const uint8_t * const *ppui8StringDescriptors;

    //
    //! The number of descriptors provided in the ppStringDescriptors
    //! array.  This must be 1 + ((5 + (number of strings)) *
    //!                           (number of languages)).
    //
    const uint32_t ui32NumStringDescriptors;

上述用户指南屏幕截图和源代码片段涉及如下所示的复合器件结构(可在 usbdcomp.h 中找到)的一部分：

在 usbdcomp.h 中找到的完整结构源

//*****************************************************************************
//
//! The structure used by the application to define operating parameters for
//! the composite device class.
//
//*****************************************************************************
typedef struct
{
    //
    //! The vendor ID that this device is to present in the device descriptor.
    //
    const uint16_t ui16VID;

    //
    //! The product ID that this device is to present in the device descriptor.
    //
    const uint16_t ui16PID;

    //
    //! The maximum power consumption of the device, expressed in mA.
    //
    const uint16_t ui16MaxPowermA;

    //
    //! Indicates whether the device is self or bus-powered and whether or not
    //! it supports remote wake up.  Valid values are \b USB_CONF_ATTR_SELF_PWR
    //! or \b USB_CONF_ATTR_BUS_PWR, optionally ORed with
    //! \b USB_CONF_ATTR_RWAKE.
    //
    const uint8_t ui8PwrAttributes;

    //
    //! A pointer to the callback function which will be called to notify
    //! the application of events relating to the operation of the composite
    //! device.
    //
    const tUSBCallback pfnCallback;

    //
    //! A pointer to the string descriptor array for this device.  This array
    //! must contain the following string descriptor pointers in this order.
    //! Language descriptor, Manufacturer name string (language 1), Product
    //! name string (language 1), Serial number string (language 1), Composite
    //! device interface description string (language 1), Configuration
    //! description string (language 1).
    //!
    //! If supporting more than 1 language, the descriptor block (except for
    //! string descriptor 0) must be repeated for each language defined in the
    //! language descriptor.
    //!
    //
    const uint8_t * const *ppui8StringDescriptors;

    //
    //! The number of descriptors provided in the ppStringDescriptors
    //! array.  This must be 1 + ((5 + (number of strings)) *
    //!                           (number of languages)).
    //
    const uint32_t ui32NumStringDescriptors;

    //
    //! The number of devices in the psDevices array.
    //
    const uint32_t ui32NumDevices;

    //
    //! This application supplied array holds the the top level device class
    //! information as well as the Instance data for that class.
    //
    tCompositeEntry * const psDevices;

    //
    //! The private data for this device instance.  This memory must remain
    //! accessible for as long as the composite device is in use and must
    //! not be modified by any code outside the composite class driver.
    //
    tCompositeInstance sPrivateData;
}
tUSBDCompositeDevice;

Question：

1.我应该只遵循结构源代码中的注释,字符串 desc 指针,说明以下是必需的{language desc, manf name string, product name str, serial num string, composition dev interface desc string, configuration desc string}?  我提出这个问题、因为这超出了用户指南所说的数量。  

2.字符串应该是什么格式？  下面显示了一个 hid 字符串描述符示例。  我是否应该复制粘贴这些内容并只更改复合字符串的内容？

//*****************************************************************************
//
// The languages supported by this device.
//
//*****************************************************************************
const uint8_t g_pui8LangDescriptor[] =
{
    4,
    USB_DTYPE_STRING,
    USBShort(USB_LANG_EN_US)
};

//*****************************************************************************
//
// The manufacturer string.
//
//*****************************************************************************
const uint8_t g_pui8ManufacturerString[] =
{
    (17 + 1) * 2,
    USB_DTYPE_STRING,
    'T', 0, 'e', 0, 'x', 0, 'a', 0, 's', 0, ' ', 0, 'I', 0, 'n', 0, 's', 0,
    't', 0, 'r', 0, 'u', 0, 'm', 0, 'e', 0, 'n', 0, 't', 0, 's', 0,
};

//*****************************************************************************
//
// The product string.
//
//*****************************************************************************
const uint8_t g_pui8ProductString[] =
{
    (19 + 1) * 2,
    USB_DTYPE_STRING,
    'G', 0, 'e', 0, 'n', 0, 'e', 0, 'r', 0, 'i', 0, 'c', 0, ' ', 0, 'B', 0,
    'u', 0, 'l', 0, 'k', 0, ' ', 0, 'D', 0, 'e', 0, 'v', 0, 'i', 0, 'c', 0,
    'e', 0
};
//*****************************************************************************
//
// The data interface description string.
//
//*****************************************************************************
const uint8_t g_pui8DataInterfaceString[] =
{
    (19 + 1) * 2,
    USB_DTYPE_STRING,
    'B', 0, 'u', 0, 'l', 0, 'k', 0, ' ', 0, 'D', 0, 'a', 0, 't', 0,
    'a', 0, ' ', 0, 'I', 0, 'n', 0, 't', 0, 'e', 0, 'r', 0, 'f', 0,
    'a', 0, 'c', 0, 'e', 0
};

//*****************************************************************************
//
// The configuration description string.
//
//*****************************************************************************
const uint8_t g_pui8ConfigString[] =
{
    (23 + 1) * 2,
    USB_DTYPE_STRING,
    'B', 0, 'u', 0, 'l', 0, 'k', 0, ' ', 0, 'D', 0, 'a', 0, 't', 0,
    'a', 0, ' ', 0, 'C', 0, 'o', 0, 'n', 0, 'f', 0, 'i', 0, 'g', 0,
    'u', 0, 'r', 0, 'a', 0, 't', 0, 'i', 0, 'o', 0, 'n', 0
};

结构中的注释听起来几乎像以下指向这些字符串的指针。

//*****************************************************************************
//
// The descriptor string table.
//
//*****************************************************************************
const uint8_t * const g_ppui8StringDescriptors[] =
{
    g_pui8LangDescriptor,
    g_pui8ManufacturerString,
    g_pui8ProductString,
    g_pui8SerialNumberString,
    g_pui8DataInterfaceString,
    g_pui8ConfigString
};

3. 对于"字符串数"字段(ppui8StringDescriptors 指针) ，结构源说明如下：

    //
    //! The number of descriptors provided in the ppStringDescriptors
    //! array.  This must be 1 + ((5 + (number of strings)) *
    //!                           (number of languages)).
    //
    const uint32_t ui32NumStringDescriptors;

那么、哪些字符串会计入该等式的"字符串数"部分？  前面的幻灯片中提到的所有

const uint8_t * const *ppui8StringDescriptors;

4、 通过 HID-Bulk 设备结构时,是否通过标准结构?  我注意到该示例使用了我不使用的缓冲器吗？  我的两个器件接口仅使用 USBLIB 的标准结构。  例如、我的批量项目中正在工作的批量器件接口仅使用以下结构-我删除了示例项目附带的缓冲支持。

//*****************************************************************************
//
//! The structure used by the application to define operating parameters for
//! the bulk device.
//
//*****************************************************************************
typedef struct
{
    //
    //! The vendor ID that this device is to present in the device descriptor.
    //
    const uint16_t ui16VID;

    //
    //! The product ID that this device is to present in the device descriptor.
    //
    const uint16_t ui16PID;

    //
    //! The maximum power consumption of the device, expressed in milliamps.
    //
    const uint16_t ui16MaxPowermA;

    //
    //! Indicates whether the device is self- or bus-powered and whether or not
    //! it supports remote wakeup.  Valid values are USB_CONF_ATTR_SELF_PWR or
    //! USB_CONF_ATTR_BUS_PWR, optionally ORed with USB_CONF_ATTR_RWAKE.
    //
    const uint8_t ui8PwrAttributes;

    //
    //! A pointer to the callback function which will be called to notify
    //! the application of events related to the device's data receive channel.
    //
    const tUSBCallback pfnRxCallback;

    //
    //! A client-supplied pointer which will be sent as the first
    //! parameter in all calls made to the receive channel callback,
    //! pfnRxCallback.
    //
    void *pvRxCBData;

    //
    //! A pointer to the callback function which will be called to notify
    //! the application of events related to the device's data transmit
    //! channel.
    //
    const tUSBCallback pfnTxCallback;

    //
    //! A client-supplied pointer which will be sent as the first
    //! parameter in all calls made to the transmit channel callback,
    //! pfnTxCallback.
    //
    void *pvTxCBData;

    //
    //! A pointer to the string descriptor array for this device.  This array
    //! must contain pointers to the following string descriptors in this
    //! order.  Language descriptor, Manufacturer name string (language 1),
    //! Product name string (language 1), Serial number string (language 1),
    //! Interface description string (language 1) and Configuration description
    //! string (language 1).
    //!
    //! If supporting more than 1 language, the strings for indices 1 through 5
    //! must be repeated for each of the other languages defined in the
    //! language descriptor.
    //
    const uint8_t * const *ppui8StringDescriptors;

    //
    //! The number of descriptors provided in the ppStringDescriptors array.
    //! This must be 1 + (5 * number of supported languages).
    //
    const uint32_t ui32NumStringDescriptors;

    //
    //! The private instance data for this device.  This memory must
    //! not be modified by any code outside the bulk class driver.
    //
    tBulkInstance sPrivateData;
}
tUSBDBulkDevice;

可以吗、因为看起来用户指南示例向 CDC 器件传递了我在批量示例中不再使用的缓冲器和东西。